Yes i have ridden the new s3, i liked it a lot, will probably be in the running for the next race bike (but the BMC and propel are both ahead).

That is compared to a tarmac which is not an aero stud so that's an poor illustration of a good point, in sprints at very high speeds the aero bike can possibly make a difference. I will suggest that the average cat 2/3/4 simply is not going fast enough to really notice any serious difference. I looked at 26 races this year that ended in some form of a sprint. The average distance sprint where i was in the wind was 200m and the average speed was 28mph (lots of hill finishes) comparing my CAAD10 to an s3 sprinting next to me there could be no more than 1-2mm advantage if that (which our local camera system could not tell the difference between). I am not arguing against aero road bikes, far from it as i am seriously eying an BMC/Giant/Cervelo as my next bike, i just take aero data from a manufacturer who has a vested interest in selling the aero over all mantra with several grains of salt.

Very similar. Both are stiffer than your S5, on the order of high-end road bikes now, like the R5, Giant and Tarmac.

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Damon Rinard
Engineering Manager,
CSG Road Engineering Department
Cannondale & GT Bicycles
(ex-Cervelo, ex-Trek, ex-Velomax, ex-Kestrel)

Damon-
I am curious, do you know where my soloist team (the aluminum one) stacks up against the newer S3/S5 in terms of compliance?

post edited to fix a decimal point error!


Let's do math!
Assume .3CdA for hypothetical 75kg rider going 28mph up a 6% grade for the sprint.

This will be about a 917 watt effort.

Reduce CdA by the difference between an EVO/Tarmac and an S5, which is about .025 and we get a speed increase of .2m/s

over 200 meters at 28mph that takes 16 seconds

.2m/s and that is about 3 meters



I like this example a lot because it is very plausible - 16 seconds at 900 watts is about what we Austin cat3s would be able to do, and it also resembles a situation I had going for a short strava climb of about this grade behind my old house. I kept using our light shallow tubies, because it was uphill! Then I realized it was short enough I was averaging 27mph.

Swapped on the heavy HED Jets, cut seconds off my time, snatched the segment away from a TopLocal Cat 1

woo

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Kat Hunter reports on the San Dimas Stage Race from inside the GC winning team
Aeroweenie.com -Compendium of Aero Data and Knowledge
Freelance sports & outdoors writer Kathryn Hunter

Why a weight penalty for the aero bike. Let's assume that both are right on the 6.8kg limit. I do not think the aero bike should be penalized by weight.

One day everyone will come around to my way of thinking "AERO AND LIGHT IS RIGHT". The aero is the cake and light is the icing. Minutes with aero and seconds with weight.

The scenario put forth by mike was cat 1/2/3 racing where there would be no limit.

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Kat Hunter reports on the San Dimas Stage Race from inside the GC winning team
Aeroweenie.com -Compendium of Aero Data and Knowledge
Freelance sports & outdoors writer Kathryn Hunter

Then I would be riding my sub 6kg aero bike.

I think we can all agree we are at a point now where Aero is not a penalty in regards to weight.

Well my initial thought was the same. But then I thought that the fact that he lost by mm doesn't change the fact that he isn't on an "aero" bike that could have won him the race. Losing by 1 cm is still losing by 1 cm if you're on a slower bike. Give Sagan an S5 or Felt AR or Venge and he may have taken the win that day.

Still potentially cost him the victory, independent of whatever Matteo Trentin was riding.

Is there an extra zero in there?

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http://bikeblather.blogspot.com/

I get a CdA difference of .0250 - .0275m^2 for that.

.0025 m^2 difference is only ~=2.5W

Edit: which for the conditions you described above would result in a speed difference of more like 0.21 m/s, or a 3m advantage over 200m. BTW, the 200g "penalty" for the aero bike weight only results in a .02m/s difference by my figgerin', or 1/10 the aero difference.

So, either I've stuffed this ballpark calc, or you drastically underestimated ;-)

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http://bikeblather.blogspot.com/

You are right, had too many zeros in the CdA assumption.

3 meters!

I will edit my post

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Kat Hunter reports on the San Dimas Stage Race from inside the GC winning team
Aeroweenie.com -Compendium of Aero Data and Knowledge
Freelance sports & outdoors writer Kathryn Hunter

I have almost 11,000 mi on my current model [2013] S5 VWD, so I think I know this frame well. I previously had a [2012] S5 Team (the one with the black/blue paint scheme) and a [2012] R5 VWD that I had set up exactly the same as the S5 Team, since they had the exact same geometry.

When I moved to the S5 VWD, I sized down from a 58cm to 56cm frame in order to get my drop where I needed it. On the 56cm S5 VWD that I currently ride, I run a -17 140mm stem. Not a lot of options there. So yeah, I like the decreased stack - I can probably now use a -6 stem.

I don't have any comfort issues with the S5. Just last weekend, I did 145mi/14Kft and felt fine afterwards. I fully subscribe to the Josh@Zipp Theory that 5psi of tire pressure change makes more difference in ride comfort than frame design.

I can't, however, get 25mm tires on my S5 VWD, at least not with wide Enve rims. So redesigning the frame to accommodate 25mm tires? Another nice upgrade for the new S5.

Other than the stack and tire clearance issues, the only other compromise I find with my S5 VWD (and this is the most significant one), is the handling/head tube stiffness. Having put a few thousand miles on the R5 VWD, I felt like the front end of that frame was stiffer and more precise than the S5's. It's not something I would notice in any situation other than high speed, particularly windy, descending. Shimmy at 50mph isn't fun and that is something that I have managed on the S5 but didn't on the R5. Then again, shimmy/instability is highly individualized and it could be something else that causes it, but I have almost 20,000mi on these frames and for me I do feel a real difference. So... if the increased torsional rigidity at the head tube is real, that would be a MAJOR improvement for me.

So...

• Lower (more appropriate) stack
• Better tire clearance
• Stiffer head tube/better handling

I already run a Vuka Sprint with my S5 VWD, so there is not *much* to be gained for me by switching to the Cervelo bar, but if the drops feel good and the top feels good, then yeah, that will be another worthwhile upgrade.

Basically, I can say that for *me* (YMMV), Cervelo has addressed each and every one of the issues that I have with my current bike, which I love. I wasn't planning on buying a new bike/frame this year, but damnit if Cervelo may have forced my hand!

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Amateur recreational hobbyist cyclist
https://www.strava.com/athletes/337152
https://vimeo.com/user11846099

No, sorry.

But there's this: http://www.slowtwitch.com/...perception_4571.html

Cheers,

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Damon Rinard
Engineering Manager,
CSG Road Engineering Department
Cannondale & GT Bicycles
(ex-Cervelo, ex-Trek, ex-Velomax, ex-Kestrel)

So a CAAD10/Supersix/Tarmac is giving up ~25W to an S5, and 20W to an S2/3, maybe 16-18W to an S1?

I know Mike said it doesn't make a difference to a Cat 2/3/4 but I'd disagree. For the average Cat2, just getting to the sprint is the biggest battle.

Something along those lines yes, though in the draft that difference will be less (not zero, just less) and of course the hard uphill bits it will be less.

But yeah, part of the benefit is increasing the odds that you make it to the sprint at all.

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Kat Hunter reports on the San Dimas Stage Race from inside the GC winning team
Aeroweenie.com -Compendium of Aero Data and Knowledge
Freelance sports & outdoors writer Kathryn Hunter

Not a problem. It isn't holding me back any racing. I'll work on the engine and the brain powering the tactics before I replace the bike :)

Good to hear!
"Leave no stone unturned." -anonymous
"Start with the big ones." -Damon

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Damon Rinard
Engineering Manager,
CSG Road Engineering Department
Cannondale & GT Bicycles
(ex-Cervelo, ex-Trek, ex-Velomax, ex-Kestrel)

At first i said BS, then i thought lets put those two semesters of physics to work, i had a similar number, in fact a few cm more (around 25-30cm). I know you readjusted to 3m but even 25-30cm is quite good during a sprint. Assuming the data reported to us is correct from Cervelo that is pretty impressive and the first time i have really "seen" the difference. I might be rethinking my road bike choice after next season. Thanks for the work and this provides some good fuel for thought. The new S3 handled well and put to rest my concerns of cornering issues. Overall its not a huge difference since most races are not won by wheel lengths, but you never know when that race will happen and might as well ride the more aero bike.

Side note: Interesting you said 917 watts, almost all of those 200m sprints were around 900-950w at 150lbs.

I went looking and did not see this asked/answered. What is the drag difference between the S2/S3 and the S5, all things being equal?

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Heath Dotson
HD Coaching:Website |Twitter: 140 Characters or Less|Facebook:Follow us on Facebook

Yeah about right for me too, only I weigh a lot more, I will never beat you uphill :(

lol

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Kat Hunter reports on the San Dimas Stage Race from inside the GC winning team
Aeroweenie.com -Compendium of Aero Data and Knowledge
Freelance sports & outdoors writer Kathryn Hunter

All else equal (wheels, etc.) about 4 Watts.

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Damon Rinard
Engineering Manager,
CSG Road Engineering Department
Cannondale & GT Bicycles
(ex-Cervelo, ex-Trek, ex-Velomax, ex-Kestrel)

So all things equal I lose 4 watts on an S2 versus S5?
At 5.5 w/kg I'll take that...that's a big improvement over a Caad 10....thanks

Hi bootsie,

It's about 50 cm centre to top.

Cheers,

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Damon Rinard
Engineering Manager,
CSG Road Engineering Department
Cannondale & GT Bicycles
(ex-Cervelo, ex-Trek, ex-Velomax, ex-Kestrel)