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.