Nothing. I hate the way they look. Besides, I've never been in a situation on my tri bike where I thought the stopping power of rim brakes was inadequate.

Simple - when a bike I lust after happens to have disc brakes, that's when I'll switch.

Pube's test? lol, right..

A clear, compelling and convincing argument that has yet to be made.

I can accept disc brakes on anyone's bike, but I don't want them or need them on my bike. Just don't need them. I barely use the brakes that I do have :-)
I am hoping that when the time comes that the bike that I want doesn't have them.

My biggest concern is ease of use/maintenance. I have disc brakes on my fat bike and had them on my mountain bike and they've always been a bit of a pain in the ass to maintain...primarily to keep from rubbing. Even the slightest rub drives me nuts and I've never been in a position where I felt I needed them so the potential utility isn't enough to outweigh my pain in the ass experiences.

Let others be beta testers. When majority of you are on disks, I'll switch to disks too, but only next time I'm buying a bike. I would not go out of my way to "upgrade" because it isn't an upgrade.

If disks don't catch on, then I don't want them either.

Why? Wheel swaps if my race wheels are damaged. That's why.

Whenever I am in the market for a new bike (~1-3 years from now depending what mfg's do) and I can no longer buy a superbike with rim brakes.

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I really don't understand disc brakes on tri (or road for that matter) bikes. It seems like a solution without a problem. I've spent a LOT of miles in mountains (1000s of miles in Northern Colorado)...I just can't ever recall wishing that I had more stopping power than I was able to obtain using my rim brakes. Even doing the 100 mile loop to the top of trail-ridge-road and back, in the rain...never once. Just. don't. get. it.

Now that I'm in Texas, the only time I touch the brakes is at stop lights.

With the extra components, cost, weight, complexity, and presumed aero tax...where is the upside?

I admit I'm only recently back in the sport after a long hiatus, and haven't done any research on this topic yet. So, maybe I'm missing something.

My next bike will be disc brakes... at least five years from now, when discs will have become the defacto standard for all bikes.

I'll accept it as soon as my Andean gets here.

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Any run that doesn't include pooping in someone's front yard is a win.

How about highly reliable braking on long steep technical downhills where neither the disc rotors, nor the calipers, nor the pads, nor the hydraulic fluid fail at any time in any realistic situation?

In other words, if a disc brake system can work as the primary brakes on a tandem (and currently they can't -- they fail catastrophically), then they'll work on a single rider bike too.

Finally, will such reliable disc brakes be more aerodynamic than state-of-the art caliper brakes? If yes, then I will be stunned. But I will accept them for tri.

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them not being a ridiculous money grab.

First, I need to be in the market for a new bike. Second, I would need there to be no bikes I wanted to be without rim brakes. Third, I would have to be able to get disc wheels for racing without losing too much money on selling my rim brake which would be near impossible if the switch actually hits mainstream. I don't think I have an issue with disc brakes but I have an issue with need to get new wheels along with a new bike if I made the switch.

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Here's a observation that has not been mentioned. At least I have not read of this on any thread regarding disc brakes on road/tri bikes. I was in Seaside, FL last year and friend of mine brought her Mtn Bike over to ride the trails. 1/2 thru the ride she squeezed the rear brake and the rear brake caliper froze up closed on the rear rim. Rear wheel was locked and could not turn the wheel. Had to bleed the line to relieve the pressure and the rear braked unlocked. She dropped it off at local bike shop and their response was the lack of use and the build up of moisture inside the line cause the rear brake to seize.

Can u imagine hitting your brakes at the turn around at IMH and this happens?

My take on disc brakes are this:
1) Timming is bad...people just had to upgrade wheels from 10spd to 11spd not to long ago. Now u have to upgrade wheels again but add a new frame and new hydraulics.
2) Frame manufactures rushed to make frames work for disc...for example: look at Cervelo R3 disc(lets just drill a hole in the side of fork to run the brake line...that took a lot of thought) Other companies did it to.
Frame manufactures still have not made a frame/fork that's seamless to accommodate the disc brake itself.
3) Frame/wheel manufactures have not made frame/fork/wheelsets/disc brakes that weigh the same or less than rim brake frame/fork/wheelsets/brakes.

2) and 3) should have been addressed before the big push to change in my opinion but that would have cost the manufactures money.

Also, if manufactures are going to do disc why not make the frames accommodate potentially the next increase in cogs from 11 speed to 12 speed and above?

Your question is worded poorly. I have accepted that their are disc brakes on tri bikes. Not accepting it would be like me saying that the world is flat.

Now, what would it take for me to actually buy one of these things? Well, I'd have to want a certain bike that just happened to have disc brakes. And not only would I have to want it, I'd have to want it enough to deal with selling all of my non-disc wheels and buying the new more expensive disc versions.

I don't see that happening anytime in the next 5 years. But that may be just because all of the new disc tri bikes out there right now are uninspiring.

That's when I will switch. When I don't have choice.

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Pretty much this, and to actually have enough money to buy a new bike, regardless of which brakes it has.

I think my problem is I want a new bike in 2018. Specialized will most likely have released their bike by then. Why would I want to buy a P5 frame when the P5-X and all the other bikes with disc brakes are out?

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Because it's faster.

Without data right now, that's all subjective.

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For others, I'm willing to accept them now. I see no reason not to.

For me, it'll take a miracle. That miracle would be a free upgrade of my Reynolds RZR 92 wheels.

^ This.

Also, I have not purchased a complete bike in nearly 20 years, parts and frames just get upgraded. Switching to discs would require completely starting over, which I can't really afford at this point, even if there were a disc bike that I wanted...

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There is not much aero data, but there is considerable failure data.

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The data that Cervelo has released so far shows that the P5x is only faster when the competition has been severely kneecapped. If you really think that disc brakes are faster then Mr. Tumnus is slipping something into your tea.

I talked to Cervelo about the test protocol and showed them this thread. I was told "wait for the whitepaper." I keep an open mind when it comes to manufacturer claims but I want more evidence. I have a hard time spending $5000 on a P5 frame knowing that it's a bike designed from 2009-2012.

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When I have no other choice.

What will it take disc-brake advocates to stop caring about what the rest of us use?

Pretty much

At some point, one will have no choice. Then I will switch. But knowing how many times my roadie buddies had to have their disc brakes serviced (hydraulics being the weak link), I can't see myself switching anytime soon. They don't even race so worst case scenario they don't do a ride or 2. Imagine this scenario happen in a IM that you trained 18-20 weeks for? I'd lose my shit...

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Next races on the schedule: none at the moment

Who cares when it was designed if it's faster. There's a reason people snap up the P4. Why not simply pick up an old fast frame and spend the rest on tunnel/velodrome testing? I was under the impression that racing was about going as fast as possible, so why not do it smarter?

Don't you just do TTs?

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Yes, but I do many 50, 100 mile, and 12hr ones, so your integration argument won't work with me.

I amended your statement to apply to me (and hopefully to you as well).

I read on a Canyon ad that disk brakes are 1.5% slower.
Never needed them on my tri bike. Never will.
Will they standardize the size? The expense of training wheels and varying race wheels makes it unreasonable.

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Can you find the ad?

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Yes, in addition to the other major barriers (aerodynamic and braking performance/heat dissipation issues), I think it will be essential for high performance disc brakes to also be avail as cable actuated instead of hydraulic only. In other words, we need to have a choice.

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That'd never happen - now we are talking about a frame being practically hollow with 2 extra cables running through it. How would the same set of brakes be able to do mech+hydralic actuation? You'd have to switch the cables methinks...

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Next races on the schedule: none at the moment

No, I think you may have misunderstood what I posted.

I meant that, just like now you can decide to run di2 or run mechanical shifting on most bikes, hopefully in the future you can decide to run hydraulic or run cable-actuated disc brakes. This would, of course, entail different brakes and brake levers.

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Oh I see. Yeah, that'd make a ton of sense. Different price points but ability to shift from one to another. That'd be sweet in fact.

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Next races on the schedule: none at the moment

I like the idea of this.

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What is mind blowing to me is that it's taken them this long to give us details. We've been waiting for 6 months and counting. We got a little more information from that video but it just begs for more questions. I know ST is a small population of triathletes yet other mfg's have released theirs in a much shorter amount of time. Trek was the first to release a white paper (that I know of) and they released it right at the same time as the bike. Why couldn't Cervelo do the same thing? It makes me question their claims and credibility. What are they worried about? Why does a white paper take so long to generate? If it's truly as fast as they claim, the white paper should be easy to write. And if you read treks white paper, it wasn't rocket science or nearly as complex as anything Dan writes. Very easy to follow and concise.

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When obsolesce of the current 130mm wide hub rim brake standard happens and disc is the only choice.

I have discs on:
Mountain bike
Gravel bike
Cross bike

Think they are awesome for those purposes. Control in wet environment is great and clearance of keeping debris (like leaves) out of the caliper/tire area is a bonus.

I can understand having disc's on a road bike, especially living in a mountainous region where prolonged braking and rim heat becomes an issue. I can also see them in areas of a very wet environment, like London or wherever it rains more than it doesn't

I don't see the point on a tri bike. In most TT races, I intend to stop ONE time. Dont need great brake modulation to do that. If I'm riding up a mountain that requires heavy braking on the way down, I would choose my road bike. I might take a mountain climb with a TT bike once in a great while, but not enough to warrant a new bike or new wheels. If it rains, the aluminum rims are not the best, but work well enough. I hardly ever get into a situation in a TT bike in the rain where I need to have good modulation other than to just stop.

Most triathletes probably only have 1 bike though. Disc brakes would make sense because the tri bike is their training bike too.

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Wut? Why would a training bike need discs?

You said in the other thread that if you were to buy a P5x it would be simply because you want one, but you seem to be trying really hard to justify your (eventual?) purchase to everyone else.

Only the proletariat triathlete has 1 bike.

I live in the midwest. Most of the triathletes I know that have a TT as their single bike also have an indoor trainer and now Zwift. I think Zwift is going to kill the necessity for riding in conditions that suck. That only leaves mountainous regions where it would make sense, but I cant comment on that. Only my own experience here in the flats and rolling hills.

Well...then I must be a very poor man then because I'm only buying 1 bike.

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The post by Canyon was on Facebook.
I think this is it. Scroll down to aerodynamics
https://www.canyon.com/...ntent=&utm_term=

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Team Zoot So Cal

I did ride a couple times in Colorado though. Ft Collins and Boulder areas. The mountains I did there had gentle enough descents where braking was not heavily used. I also did Mt. Lemmon, which was absolutely no braking on the way down. The only place I have been where I would give the go ahead for discs would be Mt. Palomar, descending the switchback side.

I figured given how much time you spent on ST you'd get the joke.

All weather conditions. If a person only has 1 bike, and discs stop better than rim brakes, than it makes sense that that person would probably want discs to ride in the rain or where ever. I also have no idea what I'm buying yet.

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Nope! I'm reading that article now.

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My experience with wet weather braking on rim and disc is that both will stop you in the same amount of distance. It's how it slows you down is the difference. Wet rim aluminum is kind of loose at first, then way too grabby, very hard to judge and control. Requires a massive amount of "slam" at first and then ease off to prevent skidding the tire.

Disc is a very responsive stop. All depends on how much braking you're going to do on a bike in my opinion. If you do a lot of group rides in the rain, then having discs that scrub speed accurately is nice.

You're talking crap. I've lived in a hilly/mountainous area for years where it's constantly pissing down and have never needed disc brakes. This includes going down 1:3 hills with a fully loaded touring bike. Last few times I've been in Mallorca and the Alps I haven't heard anyone say they need disc brakes despite rain. Even then over the past couple years I've built up 3 TT training bikes for less than half the price of a Neo.

So do you really thinking spending 5k on a P3x (or whatever they're cheap version is going to be) is better value than buying a P5, a training bike, and aero testing for the same money? Like I said, you're living in Narnia.

 I've ridden my P2 in mountainous areas, all up and down some hills. I was saying the argument for disc brakes is better all around braking in ALL conditions. My P2 does not stop that well in the rain!

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I have no issues accepting them today

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Lions don't lose sleep worrying about the sheep

With carbon rims, or AL rims?

What kind of brake pads?

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Shimano brake pads, TriRig Omega X brakes, and Dura Ace brake levers. Aluminum rims

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This. What brakes are you running as well.

I don't take carbon clinchers to the Alps...

Try retrofitting all 4 pads with kool stop salmons and prepare to be impressed.
They make shimano-compatible pads that will slide right in to your brake pad holders.

Because they are outstanding both in dry and wet (on AL rims), far superior to shimano pads.

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I've used them in the past. I ended up switching to the Shimano pads.

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LOL, and you wonder why your braking is poor. Swissstop or bust.

Regardless of my setup, I still think there is no stopping the disc brake train.

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Have you tried any other calipers with the kool-stops?
Tririgs, while aero, are not known for excellent braking performance.

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In many respects, I'm a retrogrouch. I don't like current carbon anything (although I can see potential in about ten years). I like steel a great deal. I don't believe a pound of bike weight matters, at all. I don't believe that aero frames and aero wheels make any real world performance difference for road bikes. However, I do like hydraulic disc brakes a great deal. I'll grant that tri / TT bikes are probably the single type of bikes least enhanced by disc brakes. However, a lot of the complaints here are a bit silly:

1. Rubbing: modern (meaning over the last two years) hydraulics are relatively foolproof to align. Loosen the caliper bolts, squeeze the lever and retighten the bolts. I have discs on three bikes and I don't have a problem with rubbing brakes. Also, brakes as increasingly tolerant of minor rotor run-out. This is only going to continue to get better. Lastly, thru-axles make rotor alignment much easier than QR.

2. Maintenance: modern hydraulic brakes are very reliable. First gen Avid and Shimano hydraulics sucked but the current Shimano road, Shimano MTB and Sram MTB offerings are all very reliable and easy to maintain. Set them up and they usually don't need adjustment for years. You need to reset the pistons when replacing the pads but that's really easy. Even bleeding is simple these days. Are hydraulics as easy to maintain as cables? Not yet, but it's not a wide gulf today.

3. Power: while they offer plenty of braking power discs were never about "more power". They are about consistent braking in all conditions and braking force modulation. I think most people would be hard pressed to say that they prefer the feel of a sidepull brake to a modern hydraulic disc.

I see no reason to prefer sidepull these days if you're buying a new complete road bike. I'd get one with discs and two thru-axles. TT/tri? I can see holding off for a couple of more years.

I accept that disc brakes are a superior method of stopping/slowing than caliper brakes. However, you need horses for courses - just as you wouldn't use a TT bike for off road riding.

Generally speaking you don't want to have to slow down at any stage of a triathlon but you need some form of speed control for turns, dismounts etc.

Disc brakes are heavier and less aerodynamic than caliper brakes and therefore reduce your overall speed slightly. Who needs that when caliper brakes are adequate for their limited need in a triathlon.

Interesting comments of disc brakes on the new Cannondale Slice in this magazine article:

http://www.cyclingnews.com/...o-adriatico-gallery/

I think a lot of people are forgetting the ability to reduce the frontal area of the bike slightly by not having to make head tubes and forks as wide as brake calipers. Is there an aero gain from redesigning wheels? Possibly but it's small.

I believe the overall system of a disc brake tri bike can be faster factoring in everything as a whole. Everyone is focusing on the brakes and wheels when it's the entire system that matters. I'll gladly be proven wrong but this seems to be what Cervelo, Specialized, and Cannodale are saying.

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+1

Ad Muncher

Total bullshit. All of it.

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I disagree. If I can make a head tube and fork slimmer because I don't have to make it as wide as rim brakes, then that should reduce the Cda at low yaw.

So basically all the engineers at 3 different bike companies are wrong? Lying about data?

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Show me the front end of a disc braked bike (INCLUDING wheel differences like spoke count...since you're all about the system, you know ;-) that's more aerodynamic than THIS (including power to rotate) and we can talk. Otherwise, just shut up.


Besides, I thought you didn't care if it was faster or not :-/

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I should shut up? I think you should drop your ego.

These discussions need to be had instead of being dismissed as marketing claims, bad science, or how HED Jet's are God's gift to Triathlon.

No, I won't shut up.

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So far I haven't seen a front hub that doesn't probably negate the advantage of a narrower fork crown. Then add the additional spokes and lacing of the disc brake wheels and it gets really hard to believe there is much of an aero advantage.

I am not opposed to discs, but I don't think there are big advantages for a Tri/TT bike. As for whether I wil upgrade anytime soon? I don't think so. I am too invested in equipment that isn't disc friendly. For example, Powertap hubs don't work. My Specialized trispokes. 18/20 spoke Firecrest 404s, Campy EPS levers.... My hope is that discs make the rim brake bikes I covet cheap, so PM me if you need to unload that Madone 9.x or P4!

That's something I've been wondering about is the hub size and spokes. I just checked the Zipp 808 Disc Brake and it uses CX-Ray spokes but a different hub than the old 808 Firecrest or NSW.

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You fancy the P5x because you think it will make you look like a cross between Chris Boardman and Tron, and you keep creating these threads hoping that the folks you respect on here will validate your choice. The problem is, it cannot be validated with data available today. The other thread where you started by posting a paper on aerodynamic "testing" and then backtracked to "I like the way it looks", and now this one, suggest to me that you just really really want Tom A to tell you it is ok, you made a good choice. If jackmott still posted on here you would be sending him daily PMs with glossy soft-lit photos of disc rotors, mounted to a beam bike leading a race ahead of a triangular frame with 64 gels selotaped to the top tube, a 750ml round bottle attached crosswise to the seat tube, and probably a wicker basket full of flapjack hanging off the aero extensions. But lots of folk on here who understand the scientific method won't approve of your choice, if you decide to buy the P5x.

For me, I will buy disc braking products for my TT bike when obsolescence forces me to, or I see a fair test comparing a leading rim brake bike to a disc bike, both in optimised race trim. And on that day, you will have to pry my last-production-run P3C with its proper race geometry out of my unwilling hands.

I've got Tririg Omegas on my P3C, with some fairly tight turns in the cable routing, passing through my Sigma stem. I ride the bike in the pissing rain (not much choice in Yorkshire) and when I need to I can squeeze the little SRAM aero levers hard enough that my rear tyre locks up, and if I wanted to I'm pretty sure I could endo myself over the front of the bike. The brake caliper is not the weak link in this friction contest, it is the tyre in contact with the road.

And honestly, if it is a discussion about brake actuation and modulation I believe that the vast majority of issues can be sorted out with compressionless segmented cable housing.

Totally off topic, but for some reason I thought last night how I always liked Jack's posts, but I could not remember his name. For training and using a power meter he seemed like he was very rational and had a good writing style. Well at least IMO. Thanks reminding me of his name :-)

It's actually pretty amazing how few people give a shit about these discussions. The ratio of views to posts for these threads is the lowest on Slowtwitch...meaning nobody even wants to lurk around to hear this nonsense. Because it's the same ten or 15 people prattling on with the same tired tune. There aren't any new facts; there are only feelings. Which is the most useless type of debate.

So I'm going to go ahead and agree with Tom A and say that you should shut the fuck up. As should he. Until there is something new to talk about.

I hate all of you.

It seems as though this question is being interpreted in two different ways :

1. When will you be ok with other riders using discs? My answer is unequivocally now. It doesn't impact me at all.

2. When will you use discs yourself? My answer is I will use them when I need a new bike and the bike I want has discs.

I have discs on my mountain bike, and I'm pretty sure that I'm about to buy a road bike with discs. I like that it gives extra clearance for wider tires, which will make this a nice gravel bike too. I don't race, so it doesn't matter that UCI changes (that may never happen) haven't trickled down yet.

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Munq

"So I'm going to go ahead and agree with Tom A and say that you should shut the fuck up. As should he. Until there is something new to talk about."

milo, it's not all about you.

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Dan Empfield
aka Slowman

+1

I have a mountain bike with disc brakes and a gravel bike with disc brakes. I haven't had them long enough to run into maintenance issues but I suspect I will. On road bikes and tri bikes I just don't see the need. Maybe people in hillier areas with steep descents have different experiences but where I ride I've never had issues with stopping power and V-brakes just require little maintenance. They seem so simple compare to disc brakes. I want fewer things to go wrong with my bike. It's same reason I considered 1x on my gravel bike. One less thing to go wrong and require maintenance.

Teeeeechnically, this is faster at 0 yaw (simply couldnt find head on shot of stock colors). So why are there even arguments being had about the need to make things slimmer? That's not very slim at all compared to the SC - but its faster at 0 yaw.

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"One Line Robert"

Ummm ....

You haven't been on internet forums much, have you?

Other than breaking news, there really aren't any "new" topics to talk about. Even your ST threads (which have been mostly entertaining) are re-hashes of things that have been brought up here time and time again and again and again and again ...

Also 90+ replies and counting means that there are people out there that are at least somewhat interested in this particular re-hash.

Just sayin' ...

;^)

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+1

I have no strong feelings against disc brakes. What is the issue with these again? Ugly? Not aero? (Not proven?) Killer ninja discs?

I have them on my MTB, i have no issues except that I hate working with hydraulics, but I'd ride them and I can learn to work hydraulics, I have rim brakes on all my rides except MTB and have absolutely no issues with that. But rim brakes are from around the 1920's and im open for future tech. so, yea. I'd ride them.

Like if I get offered a free DB Andean i wont be like "nah bruh, wont ride it. I dont do discs" haha. (I would ask if I could put my rotor chainrings on it though)

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Swim with swimmers, bike with cyclists, run with runners. Train with those who are hard to keep up with. Soon you will be hard to keep up with.

Excellent point.

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Wrong. I keep making this threads because I'm interested in the turning point of Triathlon bikes which is the P5-X and the Andean. I'm fascinated with the how and why of bicycle design and I think it's fun to talk about.



While I respect his knowledge and have asked him questions in the past on the forum and in private message, I adopt the wait and see approach to disc brakes instead of dismissing them. Also, if you are referring to the thread where I posted pictures of Cervelo's test setups, yes, I like the way the P5-X looks. You may not? Do I care? No.




Being an engineer, I think I have a solid grasp on the scientific method.

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This might be an interesting read for you, much of it applies to traditional bikes too. My complaint with disc brakes on high speed road applications is that disc brakes do not work well. And that is far, far more important than any other consideration.

See section toward the bottom of the page, "understanding braking", and there are a number of related links at the top right of the page that explain other disc brake limitations:
http://santanatandems.com/...standingBraking.html

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What I don't understand about these threads is the lens people are viewing them through. Why should Bryan care if the disc break P5x is 20s slower over 40km @ 40kmph? Why should any of us? We are not eleite professional athletes racing for money or a living.

1. Can he ride at a sustained 40kmph?
2. Is he competing for prize purses?

I don't understand why age group athletes are worried about an additional 20s when they are MOP or even FOP but not the dominate winner in any particular race. I've seen a guy with an old Pinerello without a working inner ring win a major independent race and place top 5 in an Ironman race. Why are we even debating these "aero losses" when it is a moot point anyway?

@Bryan buy the bike you want to ride and train on most and ignore the aero "penalties" and consider the financial penalties of owning a high end super bike for your side hobby. Nobody needs to validate your purchase other than you and your partner.

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"Train so you have no regrets @ the finish line"

Well...he didn't say what type of engineer...so truly understanding the implications of what's in that article might not be in his "wheelhouse" (pun intended ;-)

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rim brakes are lighter, cheaper, and i can repair them myself. any 'speed gains' in tri are way out at a bleeding edge that i don't care about, and can't justify until i've actually reaped way, way bigger gains from basic stuff like diet, physio, sleep and so on. i'll keep riding rim brakes until i can't buy them any more, just like on my mountain bike and 'cross bike.

-mike

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____________________________________
https://lshtm.academia.edu/MikeCallaghan

http://howtobeswiss.blogspot.ch/

Can I ask what your issue is with me? I'm an Electrical/Computer engineer.

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No issue at all.

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The driver for disc brakes in tri bikes will be cheaper bikes when taken as a whole.
Once serious production starts, Ultegra level brakes will cost the same as XT brakes and smart people will be electric for gearing.
Total cost of ownership including aero wheels will be cheaper than current similar level specced bikes.
Frames will be designed around easily routed brakes and either wires or wireless.
Wheels will be far easier to design and cheaper to build.
Bike builds would be quicker, as will maintenance.

I'm a tt guy and not a triathlete. I have no want or need for disc brakes hanging out in the wind on a tt bike. The brakes on my speed concept work just fine. On mtbs they are a must however......

Disc brakes that don't squeal... and aren't slower... and that easily disconnect for travel.

When they make me faster than a similar investment in Ostarine.

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***

As soon as they come up for a reasonable explaination for the Moto of "Hide Everything!!!!!! IT must be out of the wind." To "disc brakes in the wind, those are completely fine, faster even!!"

They're too heavy. And the hubs are heavy to boot as well! In fact, tri bikes in general are too heavy! ;-)

Agreed. Same reason I still run a 10 speed. The sport is already expensive enough. When I'm forced to I'll upgrade.

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I still lapped everyone on the couch!

I thought his name was Kiley?

I like them and would rather all my bike have discs... only my mountain bike does though. That said all my other wheels aren't disc compatible, nor are are my bikes.... would be a major upgrade with 2 kids in college right now.

It is. Dan is comparing Kiley to Milo Yiannopolis.

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Why insult Milo?

Tell me about it...brand new pads on my all-road bike. Fully bedded and quiet. Today, one 6 mile, twisty, 8% average grade descent later (Gibraltar Rd.) and it's squeal-city every time they're applied now. Not unusual for the descents around here (Gibraltar, Painted Cave -Old San Marcos, etc.)

Annoying :-/

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He already used Rush Limbaugh, Milo was just next on the list.
http://forum.slowtwitch.com/...ost=6217845#p6217845

Yeah...stan has given up on engaging me intellectually, or responding to what I say with any substance. Now he just slings mud. I guess I don't blame him, given how those previous discussions ended...in him slinging mud.

When I update the bike, if the new bike has them then I will just run them. I suspect it will be the future of bikes and somewhere along the line people will have to jump in as they have with every other change as it becomes the only option apart from buying an old banger. Admittedly, I do like the thought of having the power and control of discs, I think they are just that much better than rim brakes, especially if wanting to stop in the wet and also in terms of not destroying carbon rims when the pads are mixed up with wet grit. It sounds like the manufacturers think they can offset the aero losses from discs with frame and fork changes, thats great, although they don't look very aero to the eye. Hopefully into the future they can make disc callipers etc more aero, but that said, generally speaking I don't think most derailleur and rim brake manufacturers have ever really had a good crack at it. Discs will probably be a bit like Di2, don't need it, doesnt make me go faster, waste of money, more to go wrong, but once people get it then they like it and want it.

Anyway, if the next bike I want has discs, then I'll just run with discs. If there is an option (like in the S3) then I will probably choose to go discs for the better brakes, ease of use and longevity assuming they are as good as my MTB brakes. I know on here integrating discs is like the sky is falling in, but I don't agree with some of that discussion. Discs will be the future, get aboard....but I would just wait until TT bikes have a full hydraulic disc setup - I cant believe Magura don't have this already.

Hydraulic TT levers will be here by the end of the year.

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Again, not claiming this is scientific (or not), but this brave mechanic seems totally unfazed by the "danger" of disc brakes.

super short video link, no fb account needed:
http://m.nieuwsblad.be/...?utm_source=facebook

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Ok so they are less aero, all be it small, they are heavier, and they are a solution without a problem.....why would you use them on a TT bike? I will not be switching anytime soon.

because folks that turn one word into three don't care?

And your point is??

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As with anything new the correct question is not: why don't you want it?

The correct question is: why do you want it?

As with anything tt related, the answer is because it makes you faster. And to be clear, faster under reasonable circumstances which do not include strapping parachute like devices to rim brake bikes and testing against them.

Meh, not sure. Disc brake threads usually seem to me to be mostly populated by the anti-disc crowd.

I will make sure to revisit this thread 5 years from now to laugh at the anti-disc crowd.

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You'll have to catch us first. :P

I'll already be in T2

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Smart testers don't mess with 3 sports. ;)

Interesting how much more power it took Mullen to beat Dowsett in the TT a few days ago. Wonder what it's down to...

Can you post a link to it?

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Seeing a lot of the same comments here as anywhere on the internet when a discussion of disc brakes comes up.
I'm not a member of either the pro- or anti- disc religions.
Like a lot of things, there are pros and cons and things we don't know yet.

I like the disc brakes on my touring/rando/gravel/commuter bike. Panic stops in traffic, trying to control speed down long hills with a heavily loaded bike, optimal brake performance in bad weather - all reasons related to how I use my Volagi.
But none of those factors apply to my tri bike.

Plausible argument in favor of disc tri bikes: Some aero gurus think they'll be able to design more aero wheels without the brake track, and believe that will more than compensate for any drag due to the discs and calipers.
Sounds possible, we will see.
I am not going to replace my tri bike AND wheels just for a marginal aero gain, however. The cost-to-benefit mix does not add up for me.

Some of the objections to disc brakes others have posted don't make sense to me.
- Disc brake failures: OK, so that has happened in some tiny fraction of situations. Overheating rim brakes and having them fail or fade is another vanishingly rare phenomenon. Not going to base a decision on a freak occurrence that almost never happens either way.
- Weight: The difference is not all that great, likely to become less as designs are refined, partially counterbalanced by losing the brake track off the rims (which if you're a weight weenie is further from the axle and a better place to lose weight from). Last but not least, check out the FloCycling data on weight versus aero - hint: aero wins unless you're climbing one of the epic grand tour mountain stages, and even then, weight is only marginally more important.

Bottom line, I have no plans to replace my tri bike any time soon and if I had to replace it, I'd be shopping for a rim brake bike so I could keep the same wheels.
But if I was starting with a clean sheet, I'd have no objection to a disc brake tri bike. If I was in the market and the bike that best met my criteria for fit, performance, and price happened to have discs, I'd buy it.

Ryan Mullen - 11:11 @ 458w (Strava)
https://www.strava.com/...segments/21931029652

Alex Dowsett - 11:11 @ 441w (Strava)
https://www.strava.com/...segments/21930710311

I'm not sure your time/watts are correct. Mullen looks like he was 11:35 (moving time) vs. 11:55 (elapsed, prob started his watch prior to 'go' as would I in TTs) @ 463w. Dowsett was 11:45 @ 443w. So a 20w differential equating to 10 seconds over 10k. That's pretty close to being about what you'd expect in terms of "rule of thumb" aeroness. Or, within 10 seconds.

Sure you won't be retired for the 4th time by then?

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Nah, I'll just be going faster than you as we get older.

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There's a reason I took the segment as opposed to the whole ride. The official results have Dowsett 1sec behind Mullen, so when they started/stopped their Garmins isn't comparable.

Ah gotcha, my Strava analysis was flawed. So 17w for 1s of time. Also interesting how much higher of a max speed Dowsett hit vs. Mullen, although Strava has pulled odd data for my rides before regarding max speed.

And what is going to be your criteria/data point that proves the anti disc brake crowd was wrong? Honest question.

Is it based off what the mfg's are making? Is it based off number of disc brake bikes at races?

We all argue about this and each side wants to be right. But what's going to be the deciding factor on who's right?

Because at the end of the day we all know, we each want to win the argument. :)

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blog

You can really stop it with your thumb? If this video is true that what is the big story?

I am ready right now. My road bike is from 2000. The only things that have changed since then are two more gears 9 to 11, DI2, and Disc Brakes.
My tri bike is from 2008. 10 gears, no DI2.


Give me the new technology!
John

Permission from TriSpouse and appropriate cash in hand.

Here in New Zealand, the rain and sea spray make rubber rim brakes ornamental about half the year. I long for a whole quiver of hydraulic disc equipped bikes. I've even considered (shock horror) selling a bike to get money and space in the bike shed, for a disc equipped road bike. Hell, I might even sell one of my 3 tri bikes to upgrade to a disc tri bike too. but that would really mean I'd have to start racing again, and that might be what stops me :-)

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TriDork

"Happiness is a myth. All you can hope for is to get laid once in a while, drunk once in a while and to eat chocolate every day"

Sure you can stop it with your thumb...when it's like that. It's a totally different prospect during the actual use case and conditions.

Under the right conditions, you can gently press your thumb against a sharp knife blade and not have it cut you either...but, that doesn't mean it's perfectly safe to go flinging them around with mass (inertia) behind them, or to quickly jam your thumb (or other body parts) against it, now is it?

Physics really must be a hard thing for most people to understand...

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Probably when hell freezes over. But only b/c I'm cheap and want value out of my purchases. Heck, my training bike is a 1997 Cannondale CAAD3. Fits great. Must have 50,000 miles on that thing. Replaced the STI once, everything else (minus consumables and crash damaged bars) is as I built it in 1998 (purchased as a leftover frame/fork). Raced that until two years ago, and bought a 2009 QR CD 0.1 for racing. Why? Some bit lighter, way more aero and less hassle in swapping the special carbon-only pads before/after race day (the carbon wheels now stay on the dedicated race bike).

Well, I train on the QR a little and race on it a few time per year. It probably gets 500 miles per year. Based on my experience with the CAAD3, I guess that I could ride it for 100 years! BUT, not if we're all going to new technologies - 15 speed rear cassettes, thought-triggered shifting and, yes, disc brakes. Each of these advances costs $ to retrofit to existing bikes that operate *fine*. And I'm too slow to be seeking marginal gains as part of Team Sky. So, really, what is the advantage in a race bike for disc wheels? Sure, edge case of long descents on full carbon wheels. If I lived in the Alps... Better wet braking - ok. But neither of these has caused me any significant troubles in the past. Sorry, we are not heavy enough or fast enough to really justify disc brakes on race bikes in the same way that they make sense on motorcycles and cars/trucks. So, if you've got the $ and want the latest, go for it. Just sell me your three year old superbike for a few $100...

You didn't have to add the last sentence. That's just piling on.
Thanks for the perspective.
John

Well that illustrates the point. I've been hearing similar things about electronic shifting for... what... 8 years now. Like it matters...

It's like saying something nice about Windows on Slashdot. Or drawing a picture of Mohammed in front of an ISIS member. Not as drastic as saying something nice about tubulars around Tom A, mind you. :-), but right up there.

Well, the problem with those videos is people take them as "proof"...without thinking things through. It's just frustrating to have them posted over and over again...

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I don't hate tubulars...they're just OLD technology. We have newer/better tech. Why are pro cyclists still using that old-fashioned method of mounting tires when there's newer technology tires they could use? What other high-performance wheeled vehicles still GLUE tires onto rims?

Sound familiar? ;-)

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So you don't ever ride your tri-bike in traffic or the rain?

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'It never gets easier, you just get crazier.'

Very rarely in traffic or rain, and never with 20+ extra pounds of pannier luggage on board.

I definitely agree my disc brake bike has superior braking performance, and I suppose if you offered to wave a magic wand and convert my tri bike and race wheels to discs, I'd take you up on it. It's just not such a priority that I'd go out and buy a new tri bike and wheels just to get better braking.

To be honest, I am not really sure.
But it was an interesting demo.
But it's not one that I am going to run out and replicate ... because I like my thumb.

To summarize, there are 3 completely separate issues with disc brakes, and there is a lot of confusion on the the conflicting data avail, and the issues all get mixed up (here and other places) constantly:

1) Can a state of the art TT/Tri bike include disc brakes, and is such a bike truly more aero than a optimized rim brake TT bike?

2) Are disc brakes truly more effective and more safe (safe in braking action) than optimized rim brakes for ROAD use? (There is little argument that disc brakes work great off road, mostly because rim brakes are crap off road, it is in high speed and high kinetic energy ROAD applications that disc brakes can have some unfortunate and scary failure modes ... )

3) Then, finally, are disc brakes safe (safe in impact or crashing) in peloton racing or training?

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This really needs to stop being said. The P5, Speed Concept, Felt IA, etc. are all OPTIMIZED for rim brakes.

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I think I was not 100% clear.

I did not mean, a TT bike optimized FOR rim brakes.

I meant, a fully OTHERWISE OPTIMIZED TT bike with rim brakes.

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What does that even mean? Everyone keeps saying that with no ability to define what that means. The front ends of these bikes are all designed around that rim brake. Therefore, it is optimized for rim brakes.

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To start,

An optimized disc brake TT bike would be designed to be as aero as possible using a state of the art disc brakes, an optimized disc brake frameset, and an optimized disc brake wheelset (with appropriate rims, hubs, spokes, and spoke count), etc.

An optimized rim brake TT bike would be designed to be as aero as possible using a state of the art rim brakes, an optimized rim brake frameset, and an optimized rim brake wheelset (with appropriate rims, hubs, spokes, and spoke count), etc.

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We....already have all of that.

The P5-X and Andean were designed to be faster than rim brake bikes. You can argue all day long about the test protocol but I'm going by the charts.

Magura brakes are not state of the art? P5 or Speed Concept is not optimized? Zipp 808 NSW and Disc is not optimized rim brake wheels?

We are already at the optimized rim brake bikes and wheels.

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I am not saying that we do not have rim brake optimized bikes.

What I am saying is that, to the best of my knowledge, good 'apples-to-apples' aero equipment comparisons have not been done (in the public data realm).

The P5X and Andean are cool, but they not like any other bikes previously, so it is very hard to compare them to other state of the art rim brake TT bikes. If you change a lot of design variables at the same time with new bikes, it is really hard to know what makes it faster or slower (based on public data, of course).

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If you think the bike companies have enough money to separately develop a "state of the art rim brake" bike and a disc brake bike, you would be wrong.

The test protocol from Cervelo is the best test setup data we currently have. Comparing the P5-X to the P5 is a fair comparison and represents the best of what Cervelo has.

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Wait...isn't there a YouTube video with the designer of the Andean admitting it would be faster if it had been designed with rim brakes in mind?

And are you really hanging your hat on the P5X being faster than other bikes, when tested with random gels taped to stems?

The true believer is gonna believe, I guess :-/

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Sure, you can compare the P5 to the P5X aerodynamically. Yes, they are totally different bikes, but a comparison is completely fair. You are comparing old tech to new tech.

But you can't use the bike comparisons (at least not fairly) as an indicator as whether or not a disc brake TT bike is aerodynamically superior or not.

That is what I am trying to say.

Greg

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Yes, you can. When do you draw the line? Even if Cervelo released an updated P5 in 2017, then released a P5-X in 2020, you would still hear the same arguments. The P5 was Cervelo's best effort at rim brakes from 2009-2012. The P5-X was designed from 2013-2016. You have to draw a line somewhere and say "we are going disc brakes".

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You mean like the Specialized Venge ViAS disc-, and rim-brake versions? Or the Specialized Tarmac disc-, and rim-brake versions? Or the Cannondale Slice disc-, and rim-brake versions?

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You did not understand what I was saying. No company is going to pour a ton of money to make 2 separate "best of class" versions of their bikes just to make Tom A. happy and then say "oh, disc was faster let's throw away the rim brake bike molds".

Decisions have to be made on what path to take. The bike companies have already told you the path they are taking.

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Also, do you honestly think Specialized is going to release a rim brake version of the new Shiv? Nope.

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Pubes mentions it here: http://forum.slowtwitch.com/forum/?post=1324075

Interestingly enough, that interview video is no longer available on YouTube...hmmm...

I also recall that statement in the video though...plus, I had a brief conversation with him at Interbike on the subject as well.


And yet you take the "charts" as fact without the context of the test details? Ummm...OK... :-/

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You are putting words in my mouth again.

I said I was comparing on the charts AS THAT IS ALL WE HAVE. All Caps should make that a bit easier to understand. We have no test data on the Andean beyond what they offered. We have photos and no white paper from Cervelo. You guys are impatient, cannot wait for more clarity and data, and are acting like it's the end of the world. I'm sure you will counter with "I'm an idiot, I'm blind to the data, I'm a Cervelo fanboy, etc."

Chill and wait.

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I'd be surprised if they did not release two versions of the Shiv tri bike; two versions of this bike would give them a bigger market. I'm NOT so sure they will update the Shiv TT w/ a disc option. From what I understand, the demand for this version is a lot lower.

But I guess we'll see...

N=1: I'm a Shiv owner. If I were given an option to move to a Shiv disc-brake version, or the rim-brake version for a tt/tri bike, I'd choose the rim brake, w/o hesitation.

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You do know you can't buy a rim brake Venge Vias anymore right?

The Shiv with disc brakes is coming.

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In an independent test, I'd be willing to bet that the yaw-weighted average difference between the Speed Concept and the P5-X/Andean is less than 5 watts (95% confidence) and maybe less than 2 watts (80% confidence). I'm also assuming you're not going to set the bike up to carry a f**king picnic on the top tube.

I really don't get the better braking argument people make for disc brakes. What's their benchmark, poorly setup cantilever brakes? I've rented probably half a dozen disc brake road bikes now and I've never come away saying "oh yeah that's night and day better." I've got XT-8000s... which are pretty good brakes as I understand it... on my F-Si and I never come back saying "man I wish my road bike had brakes like this". My road bike has ultegra direct mount calipers fwiw on Hed Belgiums and the braking is phenomenal.

Will the new Shiv be disc brake only? Probably. Will it be faster than what's currently out there? Probably not for short-course racing. For long-course there might be something from an integration perspective but that has nothing to do with disc vs rim. The disc brake thing is just about OEMs streamlining production.

Really wouldn't be that hard to do with CAD/CFD. Not that anyone will.

You're right. How about that (I'll cross that off my need-to-get-upgrade list).
Disappointing; the VV rim-brake is a fun bike.

I don't doubt the db-Shiv is coming.
But I'd still be surprised if it was the ONLY option.

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Time and $ to pay engineering staff. Those hours can be used for their current designs.

This whole argument reminds of Apple removing the headphone jack on the iPhone 7.

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When most of the bike manufacturers, Shimano, SRAM, Zipp, and others say "disc brakes are the future", it's pretty easy to see where this is going.

I bet I can find Di2 threads of Slowtwitcher's saying the exact same thing in regards to electronic shifting.

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Instead of thinking everything is a conspiracy on disc brakes, how about trying to actually find the video?

30 second google search https://www.facebook.com/...07340589/?fallback=1

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Parallel development of electronic and mechanical groups (which are still pervasive). Just like rim- (which are still pervasive) and disc-brake versions of bikes.

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Except it's probably far cheaper to make group sets than bike frames.

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Di2 actually offered an advantage though: the ability to shift from multiple positions.

Yes, but people still thought it was something they didn't need because mechanical worked just fine.

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Yeah but Di2 was an improvement. The only way disc brakes are an improvement is if you need to clear a large tire and/or shed mud. Look, the industry needs to be called on its bullshit from time to time. Disc brakes are only better than rim brakes in a set of circumstances that simply does not apply to TT bikes.

If you want to argue for discs, say
-It will streamline production and inventory for large companies potentially leading to lower prices
-It will allow for cheaper carbon rims
-Wheels will be stronger because they'll have more spokes
-Through axles are an improvement (not really but personally I have an unusual affinity for them)
-You don't have to worry about melting a latex tube.

You're trying a little too hard there. First you left out rain. They're unambiguously better in rain.

And most people who are really good at braking and try them say the disc brakes are just plain better.

I've heard that you can approach the quality of disc brakes with hydraulic rim brakes on a textured aluminum brake surface (e.g. HED Black or Mavic Exalith).

I don't have enough personal experience to say, but I've heard this from enough really, really good cyclists who have no conflict-of-interest in the argument. (e.g. former pros unaffiliated with industry). I can say that the P5x is the best-braking TT bike I've ever ridden. But unfortunately most TT bikes I've spent a lot of time on are horrible at braking, so I'm an easy mark.

There are drawbacks. E.g. potential overheating, aerodynamics, weight, standards, wheel swap time.

The drawbacks are significant enough for me so far, that I've never considered them. But I think you're heading off the reservation a bit in claiming they don't actually brake better.

Can I interrupt this post to ask a stupid question about disc brakes? How easy is it to remove and install wheels with disc brakes? Sometimes installing a wheel with caliper brakes the wheel is installed slightly off center which will cause the rim to rub but you can easily correct. Wouldn't it be much harder to install a wheel with disc brakes as the opening for the disc is very small/tight so there is no room for error. Wouldn't the wheel need to be perfectly centered to prevent rubbing?

I ask because I always pop my front wheel off to get the bike in the car.

Just curious what Kevin told you at Interbike? Because the primary reason I bought the Andean is because he told me that he honestly did not think rim brakes would have been a "net gain" for the Andean. For the record, I don't believe him, especially given that, in the same breath, he promised a full white paper that has yet to materialize. But, he has since backed off from what he seemed to be saying in that video.

I'm conducting my testing on April 18th. We'll have the whole day at A2 to test the P5, Andean, Ventum, Tactical, and aero optimized Felt B2.

Why aren't we testing the P5-X? Well, because we know from Rinard that a round bottle on the downtube of the P5 costs 3-5 watt. We know from Cervelo that the P5-X is only faster by 3 watts, and also that they tested the P5 with a round bottle on the down tube (plus gels on the stem). So, QED: an intelligently configured P5 is faster than a P5-X. This isn't a debate. If you don't put a round bottle on the downtube of your P5, it's faster.

I hope the results of the testing will lend credence to the views of one cohort of this debate or to the views of the other. Which one is shown superior...well, I couldn't care less.

But then I can say, "no, you can't" and then you can say, "yes, you can" and then we could back and forth forever. Which, of course, would serve no one. So lets not do that.

If it helps, I am not a fan nor a hater of disc brakes. But, unless I am missing some huge trove of information, I think that, for high performance cycling, with disc brakes on road/TT/Tri bikes at least 3 big issues remain unresolved:

1) ALL other things being equal (after braking-specific design optimization), are best in class disc brake TT bikes more aerodynamic than equivalent best in class rim brake TT bikes?

2) Are best in class disc brakes truly more effective and are they safer (safer in terms of braking reliability) than best in class rim brakes for ROAD use? (There is no argument that disc brakes work great off road, mostly because rim brakes are crap off road, it is in high speed/high kinetic energy ROAD applications that disc brakes can have some unfortunate and scary failure modes ... )

3) Then, finally, are disc brakes safe (safe in terms of crashes, mishaps, etc.) for individual and/or group riding? In other words, do normal or rounded edge disc brake rotors post any real hazard in real-world bike mishaps?

So, to go back with your original thread question, "what will it take for you to accept disc brakes on tri bikes?", before I could decide to take (or not take) the leap, I would want a lot more objective data and info on the 3 questions above. A tri bike would not have to be superior on all counts for me to take the leap, but it sure better be superior in area #2.

Related to that, did you ever look at the braking technology pages and links on the Santana web page? Dang, there is some sobering stuff there.

Greg @ dsw

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I am not a disc brake expert, but I do use them.
Yes, fast wheel changes are way harder with (current design) disc brakes, vs with rim brakes.

That said, with through-axles, there is more precision in the wheel installation, so removing and then re-installing the same wheel is not a big deal, things generally stay aligned.

HOWEVER, if you want to quickly install another wheel, say, one with a different hub or different rotor or both, then alignment issues can cause a huge headache.

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It's definitely slower to swap a wheel with a disc, but if you're using a thru axle, the wheel ends up in the same spot each time. The caliper adjustment isn't done each time a wheel is swapped.

It ends up in the same spot with QRs too, assuming you did it correctly, but it's a less than ideal system for disc brakes.

One thing you'll need to be careful of is bending the rotor in transport. You can't just toss the wheel in the back of the car and expect it to be OK. I keep the the disc facing up, with nothing on top of it.

If you seriously think that manufacturer provided data based on biased protocol translates to real world performance then you've transcended from naive to being a downright clown.

Your reading comprehension skills are terrible.

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Speaking of downright forum n00b clown, you only needed to quote BryanD there. If your devoted fanbase wanted the 200 lines of back-and-forth prior to that, they have...the thread.

Meh, on a phone.

You said you're going by the charts. I'm saying that's a ridiculous way of supporting your contention as they're inherently biased. If I'm missing something then do tell; always happy to learn.

You are missing the fact I never said the charts were the perfect analysis. I said, and I will say it again, I'm using the charts as a comparison because that's all we have. Please enlighten me where we have other data? Oh that's right, we don't.

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Bad data is worse than no data. It causes people to draw incorrect conclusions as opposed to looking for the real answers.

Of course you failed to address the Mullen v. Dowsett power difference which is just as inaccurate as what you've put forward (the difference being I did so in jest).

I'm so terribly not sorry that I didn't schedule that into my day.

Let's do some analysis.

Mullen was on the new Cannondale Disc brake bike and Dowsett was riding a Canyon?

Ryan Mullen https://en.wikipedia.org/wiki/Ryan_Mullen is 6'2 174 pounds. Alex Dowsett is 6'0 and 165 pounds. https://en.wikipedia.org/wiki/Alex_Dowsett

So Ryan is taller and heavier then Dowsett. He did 458W and Dowsett did 441W.

It must be those evil disc brakes. Right....

So how was the weather during their individual efforts? Same wind?

The tires were the same on the bikes right? Same stack and reach? Same frame sizes?

What about clothing? What about their individual Cda? Wait a minute WERE THEY USING LATEX TUBES?

And we can go on and on and on and on and on.

You are looking to blame everything on disc brakes which is a flawed analysis.

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I like how you just passed over this above from PV.

You're funny.

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"One Line Robert"

Ohhh....you again. Sorry, I'll add you to my Google Calendar as well.

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You seem to miss fine details. P5-X was claimed to be 3 Watts faster AVERAGE from -15 to +15. I think you are smart enough to understand what average means.

Another fine detail you missed. Cervelo never claimed to put aero as #1 for this bike. You knew that right? The goal was to make as fast as the P5 minimum, and improve from there. Darn those pesky engineers.

Take the gu's off, the downtube bottles, and the aero pouch and re-test. Then, if it's truly slower, well then we can criticize some more.

EDIT: And I'm sure you will claim "oh but you missed the fine details of all the GU's." Well no I didn't. I posted the pictures to a thread and talked to Cervelo about their test protocol. The sky is not falling where I'm at so I'll just sit back and wait for the white paper to explain their reasoning. However, I'm sure there is a crisis support hotline you can call about the P5-X anger. High blood pressure over bikes is bad you know.

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Bryan. Take a step back. Think about what is getting your blood boiling. Reassess.

This is a really fucking stupid conversation.

Quoting for posterity purposes only. This is all very...amazing.

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"One Line Robert"

James, I am perfectly fine and just sitting back laughing at how hilarious this whole thread is.

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Two sentences yet no substance.

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Did you see the part where I said it was in jest? You're way too emotionally invested in discs.

Now that's hilarious! At the end of the day, I'm not emotionally involved in this. I'm just poking fun at you and One Line Robert.

You know why I like this debate? Because I'm really fascinated by bike frame design and I want to see if bike engineers can truly pull off what they claim.

That's really all it's about for me. If it's slower and they can't cool. If they can, awesome.

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Better yet...maybe this image sums it up

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Interesting how you can poke holes in my Mullen v. Dowsett comparison yet you shut down when someone does it to a Cervelo graph...

Umm...I told Cervelo I didn't understand parts of their test protocol.

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I specifically told them I didn't understand why they taped GUs on the stem, why use an Aero Pouch on the Shiv, and why they put an XLAB Bento Bag between the arms on the Ventum. I was told "wait for the white paper."

You guys think I'm a blind fool! However, that is not the case. I just refuse to accept the doom and gloom sky is falling opinion that most of you have.

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But you can't seem to accept that the P5x is slower when you get rid of all the gels?

I don't understand the whole doom and gloom thing you're referring to, I just don't think the P5x, and all disc brake TT bike for that matter, serve any other purpose than a cash grab for manufacturers. Anything that raises my CdA is bad, especially if I have to pay for the 'privilege'.

If it is then that sucks. You have to ask yourself if the tradeoff is worth it for better brakes. I look at it as a starting point for what's to come. I don't know why the rest of you can't see that.

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9 pages of it—hey, I did my part—so far.

So, we have another 991 pages to go.

Giddy-up.

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'Better' is not only subjective, but also not a primary concern (P4 is still the nuts) in a sport where going as fast as possible is the goal. If it really is a huge concern for some then a P3, Omega X, and Hed Jets will do the same job cheaper and faster.

you poking fun at my ride now??!! :)

Just jealous. ;)

Doesn't suck for you. Since you'll still blindly lust over it (won't buy it of course because, credit cards). The rest of us will keep our faster bikes with very-slightly-only-marginally worse brakes.

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"One Line Robert"

I'm not buying anything in 2017 but I'll be sure to get your approval in 2018. Nice signature by the way.

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Yeah. We've heard you say that now - 1 or 483 times.

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"One Line Robert"

I'll remind you tomorrow to make it 484.

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'

Yes, we do have optimized rim brakes and wheels. But NOBODY knows how the use of rim brakes on the P5-X would have affected its performance. Cervelo's own engineers stated that it was always going to have disc brakes because....reasons. There are a ton of advancements in the P5-X frame and pretty much none of them can be attributed to having used disc brakes. I don't claim that it would have absolutely be faster with rim brakes, but to claim the opposite is nothing but bullshit, because no one knows.

If I remember correctly, I think they claimed the front end of the bike was not possible with rim brakes. Could they have done it with rim brakes? Possibly. That wasn't in the design scope though.

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So which is it? Disc brakes are awesome and faster or disc brakes were an arbitrarily mandated selection and we have no idea what benefit they had on the design? Seems you just admitted the latter and that's why this whole push by manufacturers chaps my ass. If they're faster, great! But nobody is even remotely proving that. We hear that forks can be designed better, front ends can be cleaner, etc, and yet we see a bike with 5 (?) years of development come out with a caliper system that looks like it bolted on after 5 minutes of thought the week before production.

Optimize the fork designs, improve the integration of the calipers, reservoirs (if hydraulic), and so on and THEN come try to convince me to spend well over $1000 replacing my current wheelset. Until then, stop trying to force discs down my throat as a solution to a problem that doesn't exist.

I've tried every road disc system currently on the market (and many that aren't yet), and I have yet to find one that works better for me than my rim brake setups. I can stop faster, both in wet and dry conditions, on 10 year old Tektro calipers with KoolStop pads on aluminum rims. At this point, the only disc system I would even consider is Shimano's hydraulics, but I have no compelling reason to spend that kind of money replacing everything for no real improvement...

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"I'm thinking of a number between 1 and 10, and I don't know why!"

HAHAHHAHAHA. No one is forcing this down your throat. No one is making you buy disc brakes....yet. The current problem that exists is carbon braking surfaces. If you think HED Jets are the best thing ever, then we can't even have a discussion on this.

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SPONSORSHIP only.

You should ride what you're the most comfortable with. I'd just be a bit careful projecting your personal experiences as a general truth.

You'll note that I did say "I have yet to find one that works better for me". While on the other hand there are lots of people who keep saying flat out that discs are superior.

While testing brakes, what I've observed is that the performance of disc brakes tends to fall off faster as the rider's weight increases, as compared to rim brakes. As a Clydesdale, I've seen that a brake that works better than a rim brake for a lighter rider doesn't work as well for me. This seems to fall in line with what several tandem companies like Santana and Rodriguez are saying, that discs aren't even acceptable on tandems. SRAM, when they first introduced their road discs, had a weight limit (I don't know if they still do). For the average cyclist or triathlete discs may very well be superior, but for heavier than average riders maybe not...

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"I'm thinking of a number between 1 and 10, and I don't know why!"

Cervelo, Diamondback, and Cannondale have all introduced flagship tri/TT bikes that were built with disc brakes as a choice complete disconnected from any aero benefit they might provide. That's not the industry trying to force disc brakes on the market?


Surely you can cite the massive number of crashes and injuries that have occurred in triathlons and time trials because of the insufficient braking power of rim brakes that prove carbon braking surfaces are a problem that needs to be solved, especially at the expense of aerodynamics.

1. No one said you had to buy the bike. You can buy a P5, P3, P2, etc.
2. Carbon braking surfaces are definitely a problem in regards to wet weather braking.
3. You honestly think those brands put disc brakes on bikes without thinking about the aero impact? Right......

I think you are forgetting that most people can only afford 1 bike. They train on that bike too and want better braking.

However, we can go around and around in circles about this.

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