Have you tried Jet Blacks with good brakes? Down an extended steep descent? I have, and they actually outperform my disc setups (i.e. they don't fade at the end of the steepest part, which happens to be at the end). If you haven't, then you probably shouldn't be so dismissive of those opinions.


Nope. I have an iPhone, but I've never paid more than $100 for one...and I'm not talking about "bundle" deals either.

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http://bikeblather.blogspot.com/

Debatable. Given all of the discussion we seem to have on every thread about "outside" influences, I would say that any race data point is highly subjective. In other words, I certainly think Starky *COULD* ride 4:04 (or 4:02) on the IMFL course with any interference/assistance/etc from vehicles. But that doesn't necessarily mean that he did. I think the main reason that there wasn't more discussion along those lines on the IMFL threads - as opposed to say Brent McMahon or Tim Don't Florianopolis performances - is that everyone knows that Starky is an uberbiker. Perhaps THE uberbiker.

But I'm reminded of Starky's own comments after he had that monster ride at Abu Dhabi. He himself talked about how he blatantly drafted and sat in for the first 50-60km of the ride before breaking away and crushing it solo over the rest of the bike.

To me, race times - at any triathlon - are not really valid data; they are more like anecdotes. There are just far too many assumptions that history has shown are unreasonable when it comes to extrapolating equipment changes... Inter-athlete dynamics, vehicle interference, short courses, etc, etc.

Or, put another way, a lead motorcycle that's too close can do a lot to make for aerodynamic parity...

To me, one of the biggest pieces of evidence that the 12m draft zone - and/or the enforcement of it - is inadequate is that the differential between equipment and positions that should show up in races just doesn't...

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"Non est ad astra mollis e terris via." - Seneca | rappstar.com | FB - Rappstar Racing | IG - @jordanrapp

Agreed. We talked about my models not having 'Mini Countryman' mode. I do have levels of impact of age group vs pro drafting. It's the only way to explain bike splits when an athletes other parameters are fairly well known. The times when my modelling can't explain bulk trends in race data is when conditions (short or easier swim, more entrants) mean that there is more drafting.

Race dynamics far more important than kit at the very front of the race. But it's still interesting to look at whether things are different at 45kph to what they are at 25kph.

Thank you to everyone involved in this exercise. Especially to Kiley whose persistence and willingness to challenge truths was the impetus for this happening in the first place.

This actually makes me respect and question the Ventum more. The Ventum was designed to be the fastest way to get a person and two large bottles of water around a course, and it probably does this as well as any other bike, if not better. Doubly, when you consider that you can get your hydration without moving position. However, there are many other uses for the large bucket beneath your chest, and it confounds me that they have not offered a range of plastic tubs that also allow carrying of tubes and parts, ham sandwiches, and other things. You'd still have a lot of room for liquids.

Cervelo's original test protocol was much like Nike's Breaking Two. A nice demonstration of something, but because of the allowances they give themselves over their competitors, it was not directly comparable to running around Berlin on a cold morning in a race. They created a lot of doubt through their methods, and it was all of their own making.

There's a lot to consider in the results, and I look forward to digesting them further.

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

OR 4 tricked out to be just as fast.

Oh, and kudos on the choice of a shoulderless suit. Scrunching in the shoulders would have introduced more noise and made these results harder to interpret.

An ideal test protocol would involve a shaved head and speedos, but this isn't the 90s...

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

Just wanted to add my congrats to the testers. I think they have admirably conducted and fairly plus astutely reported on a test that many of us in and out of the industry have fantasized about. I think there are some great comments on this thread as well. In my mind, frame aerodynamics has been very low on the overall scale of "how do I get more free speed", ONCE you get to a certain point in frame design (which may have been hit with the original P3). This test seems to prove this out. Even with radical designs like the Ventum and the Andean the difference is small. Was the Felt a good baseline? It was certainly a relevant one based on price. Yes the Felt B is (now) cheap, but it was the DA more or less not that long ago so it did have some engineering horsepower behind it. I think either the steel frame or a "pseudo aero": frame would have been an interesting baseline. Maybe an open mold, or a low-end QR, older Orbea, etc. Maybe then you would see a sizable gap.Maybe. Front end choice, hydration/storage setup, clothing, helmet, are all likely more important as others have stated. Fit is undoubtedly so. Even tho I may be a "barber", I don't think anyone here would argue that the "haircut" doesn't make the man. I have no doubt Cyclenutnz and Dan will agree. These variables were all controlled very well in this study within reason - tactical tip stack and Ventum front hydration not withstanding.

I also think that some of the comments regarding individuality are spot-on. These results are valid for a guy of the tester's size, morphology and fit. For me at 6'4" on a huge frame they may well mean zippo. Heck with the huge hole I punch in the wind my ca 1993 custom Brew Tange Prestige frame might be just as fast as anything. Shift to a 5'2" woman and you are in a different universe. Then of course you have the intangibles of ride quality, animal attraction, etc that figure into what constitutes your dream bike. Maybe if you have a 70cm saddle height, are slimly built and have a nice stretched-out super-aero position the P5x will be a tiny bit faster for you. But will you have to look away every time you see it in your garage or transition area? If so maybe that matters. Maybe the outsized hole in your bank account is a positive, or more likely a negative. Maybe a used P4 with hacked Di2 and brakes floats your boat better and maybe it is reasonably as fast as anything out there.

I think the ultimate test would require several brands/models of bikes, in several sizes, available for testing at a velodrome, with fitters present, and multiple trials by an individual to figure out what bike and setup works best for them. Not cheap, not easy, not impossible...

Oh yeah - one more thought. What about unstable gusty air? Yaw is fine and everything, but I sure feel like some frames just cruise through gusty yaw conditions and others not so much. I have heard about this one race that has some really gusty, really yawed stuff happening. Maybe some frames are way better there...

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TK
ttbikefit.com

I think you really hit the nail on the head here. The big takeaway from this test is that the differences between modern super bikes is pretty minimal. As we've seen from many wind tunnel/aerocamp reports here on ST, changes in position, helmet, and clothing can result in very large changes in drag. Given a budget of say $6,000, you'd be well served by spending a good chunk of that on a trip to A2 (IMO).

Given a budget of $6000 I'd buy the P5 and learn how to do my own Chung/aerolab testing on my local velodrome for free.

I think I can happily stay on my P5-6 for a few more years, much to Ritch's dismay....:)

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"Only those who risk going too far can possibly find out how far one can go." T.S. Elliot | Cycle2Tri.com
Sponsors: SciCon | | Every Man Jack

To me this is where the disc brake bikes become attractive, namely to be able to from the USE Tula aerobars and have some stopping power. Not the ideal setup for technical courses but for flat courses this ought to be a noticible watt saving setup.

I can understand this if you're talking about the Gen 1 brakes, but that hasn't been my experience at all with the Gen 2 brakes, they are a vast improvement from the first generation and in my experience give up nothing to high quality conventional brakes.

 At the same time the he'd 3 spoke is still one of the fastest wheels, it's great that the sport moves on but I guess the smart value conscious people can get older stuff that is often faster than new stuff, like P4 or hed 3 spoke for little money.
It's Good that the sport moves forward but I guess what the test really showes is that the advances are so small that no one needs to be worried to be a fee years behind.
Ie the ones that like to spend can happily do so and the ones that don't want to spend can do so.
I guess what most be very disappointing for kiley is buying a bike that is so complicated he dosnt want to travel with and is just not faster on a flat course and slower on a hilly course than the bike it replace
And that after spending thousands and thousands on it, I don't call that advancement I call that a step backwards.

Even when lean I'm still over 90kg. My experience with brakes may differ from yours.

Sold my eebrakes to a low 60s guy, he thinks they're great. As do most. Just not enough power for me. I descend much faster on the roadie now I'm back to Campag

I am not suggesting that continual development and changes shouldn't happen irvwont happen. I just suggesting why there maybe some reluctance without knowing there will be sufficient performance gains to be worth it or at least until the industry has settled on a standard format of axel size e g. boost etc (no one wants a betamax in a vhs world). Though having said that it doesnt seem to effect road, gravel cx disc bike sales perhaps it isn't much of a factor. Change for changes same is not always progress, but it is natural to to take a few wrong turns as development moves forward.

I have made some of these changes of wheel types, but generally you can do these over time. 11spd wheels are compatible with 10 spd group sets, so when I brought a new 60mm wheelset a few years ago I brought wide clinchers that were 11spd compatible. I ran these on my 10 spd bike, often pairing the front with my tubular aero disc wheel. After a year or so using this set-up I saved a bit more money sold the 10sp tub disc and brought an 11spd clincher aero disc which I then used for another year in my 10 spd set-up, eventually adding a 90mm front and then switching to 11spd when I went to a 1x setup. I did a gradual change with bike when we changed from 9 to 10 spd and even used my old 8spd wheels as training wheels in my 10spd bikes before hand.

To get a disc brake bike as fast or faster than my current set up is currently prohibitively expensive for me (I work for the NHS and we are stuck on 1% pay increases). P5X plus training wheels plus rear disc is a lot of money.
These bikes are just a stepping stone to the future and as you point out a more affordable version will appear at some point.

As your title of the post points out It appears we are reaching the point where there are limited aero gains to be had, so it makes sense that the next developments will be looking at improving other aspects of the bike - braking, storage etc, while keeping the bikes as aero as possible.

If I was a bike manufacturer Ì would probably try and gain as much knowledge on aero disc brake optimisation via development of disc road bikes as the market will be bigger here and continue with rim brake TRi/TT bikes until the disc brake tri market matures a bit over the next few years - but that's probably why I look at health stats for a living!

It will take a while for these bikes to filter through to the masses. I was at a time trial last week and the chap in front of me got out his old Giant TCR in time trial configuration (a popular set up on the UK tt scene a while ago) to warm up on before getting out his Lotus to race on with a 7spd groupset and 19mm tyres. It doesn't seem tgat long ago that both of these bikes were atvthe cutting edge.

Tiny addition to the speed discussion: indeed no one rides 30 mph in average. But in most courses there are descents where also slow bikers reach speeds way over 30 mph. In these fast sections the difference of the bikes will be more than that at 30 mph.
The real time difference could be a lot more than the value calculated from the widtunnel results, at least on courses with a lot of descents (long descents, e.g. In Klagenfurt).

Edit: also on the flat with a head wind a slower biker reaches quickly a relative speed towards the air of > 30 mph

You might want to talk to some other high kg guys about their experiences with road disc brakes...or the tandem folks ;-)

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http://bikeblather.blogspot.com/

See lots of comments like this - my old bike is still fast enough, etc.
Did anyone ever really think that buying a new updated bike was going to be noticeably faster than a P2, which was pretty much a benchmark for years?
Getting a new bike is about wanting something new, not buying free time, IMHO.

Hey, anyone happen to remember that Lemond guy riding 54.5 km/hr for 25km on a round tube steel bike with spoked front wheel, round bars, exposed cables, aero helmet from 30 years ago, wrinkled skinsuit, shoes with exposed straps, narrow high pressure tires, exposed non-aero brake calipers.... Christ, all those aero mistakes would have cost him like 75 watts according to all the expert studies!!!

While not very familiar with that course, this is a good point. Especially if the climbs are long/steep enough that you're out of the aero position doing 15-17kph uphill. I suspect in that case the lighter(est) bike, if power was held constant across the bikes, might be the fastest.

Although I think choosing a bike for a specific course for the average triathlete(s) is not a smart buying decision. Most triathletes are going to spend more time/do more races on courses where CdA & P/CdA are more important vs weight/how hilly the course is. There was a post by cyclenutz (iirc it was by him anyway or maybe it was in the report) touching on this

It is an interesting modeling exercise though for those more extreme courses.

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Brian Stover USAT LII
Accelerate3 Coaching
Insta

A couple additional observations on the Ventum results:

I was at A2 with them in 2015 for some early testing on the bikes alone and then to do some fitting on Leanda and Alicia on their new Ventums and try to get their drag numbers down versus what they had on their previous bikes, which we did. This data was never released, but I have some of it. The Ventum did show more drag at negative versus positive yaw similar to that shown in this test but perhaps less extreme. The data I have is shown as "watts at 25mph" and there was a consistent 2-3 watt increase at 5 and 10 degrees negative yaw vs 5-10 positive yaw. Of course in Kona you are more worried about positive yaw.

In regard to the Cody's comments about front hydration, specifically a Torhans 30 reducing drag on the Ventum even with a gap to the head tube (faring), I will speculate that the reason for this is the brake faring shape. The portion that covers the head tube has a triangular profile, not typically considered a great aero shape (perhaps similar to the 0.4 Cd shape below). This has always bothered me, and perhaps the Torhans effectively allows the flow to bypass this potentially draggy shape. It would be relatively easy to round out the faring profile which may improve the flow over the entire frame section behind the head tube. .

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TK
ttbikefit.com

 A caviate to add (which makes high Yaw designs questionable to me) is that the system tends to stall outside 10 degrees at or below 20 mph. It's one of the reasons many bikes (including our Tactical) is designed to perform best from 0-10 degrees.

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Dan Kennison

facebook: @triPremierBike
http://www.PremierBike.com
http://www.PositionOneSports.com

Will try to search for that... any idea how long ago or name of the subject

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Follow me on Twitter @CK21TRHC
I use what I love: ISM, Blue70, Trek, FLO

Hi Dan,

Congratulations on what seems to be a well designed bike.

- what made you guys choose the Profile FC-35 over a standard BTA?
- did you mount the bracket regular or upside-down (ie. lower positioning of the bottle)
- could the bottle potentially be mover further back the extensions to mate better (??) with the head tube?

Apologies if any of those have been answered before.

We used the FC-35 based on testing quite a few hydration systems. My numbers seemed to be confirmed by the testing Jim Manton did at ERO Sports. However as strange as it seems we did not test a single bottle BTA. Just an oversight on my part when accumulating everything on the market.

For this A2 testing I was confident of the FC-35 and did not want to take a chance on an alternative system. Next time we are at the tunnel I will test it as well as an additional 10 mm of tilt on the extensions.

We use the low mount and push it back as far as possible.

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Dan Kennison

facebook: @triPremierBike
http://www.PremierBike.com
http://www.PositionOneSports.com