http://www.bikeradar.com/...ched-for-2015-42254/

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Suffer Well.

21 watt savings!*




*at 200mph

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http://www.onelesshiker.com
http://www.twitch.tv/1horsepower

This article gives a breakdown of where the savings come from:
http://www.bikerumor.com/...s5-plus-updated-rca/

and they are at 30mph:

1% – seatpost
2% – rear brake
3% – front break
5% – rear wheel
9% – drivetrain
9% – bottle
9% – fork
16% – frame
16% – front wheel
30% – handlebar

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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

Yeah -- 51% is from bars and wheels, which can apply to any bike, including the old S5.

right, and 9% is drivetrain

so only 9 watts improvement over the old S5

still amazeballs

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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

Cervelo said old S5 = P4 (with stack normalised) and Tri mag testing vs Plasma 3 backed up that S5 super quick
Given that there is a 3w difference between P4 and P5 (at 30mph using Mavic Kona yaw distribution [=windy]) - should Cervelo just ditch the P5 and have S5R and S5TT geometries?

And I'm very pleased about the 2cm stack reduction - it makes the 58 pretty much like a custom frame for me :-)

The writing is unclear, but it seems those numbers are just the total drag of each part (presumably on an S5). It says nothing about where the savings of 21.3 watts come from outside of the 4.4 watts on the handlebars. The handlebars account for 20% of the of 21 watts. I would guess much of the rest comes from the wheels. Would be nice to see an actual breakdown of the frame/fork. Nonetheless, that breakdown is very interesting and should help other manufacturers calculate where to put their efforts.

Also, I wonder if the lower headtube accounts for much of the change (in new vs. old s5). It really seems like a much better race bike (stiffer in all areas, and much better looking) but with marginal gains in aero. Tip of the hat to Cervelo for creating a faster, more complete bike even if they were a bit loose with their numbers.

That can't be total drag: bars aren't more than frame.

In any case, you can't really separate drag experimentally, since everything interacts with everything else. You can separate sources of advantage, though, to some degree.

>That can't be total drag: bars aren't more than frame.

Why not? It's plausible to me that round bars having more drag than a slippery frame.


>In any case, you can't really separate drag experimentally, since everything interacts with everything else

They did it in CFD, not the wind tunnel.

That's not the drag SAVINGS. That's the drag contribution of each component to the total drag of the bike. They used that to prioritize where they would invest their time and resources for the update. The handlebar is the biggest culprit so that was a priority to improve.

think about the position/location of the bars and how much of their total area is directly exposed to drag, especially with standard round tubes - ~44cm wide with big loops hanging off either side. The frame is mostly hiding behind the front wheel and head tube and has an extremely think profile compared to the bars riding down the road like a car with the doors wide open.

Nope! Read the last few paragraphs, photo is in the gallery

http://www.cyclingnews.com/...-in-to-paris-roubaix

 

>Nope! Read the last few paragraphs, photo is in the gallery

Hmm. OK. I got nothing.

Typical CdA for the older S5 was around 580 cm-squared (Bicycling Magazine: 600 "grams"). For the handlebars, it's a lateral cylinder, which is around 40 cm multiplied by 2.6 cm = approximately 100 cm-squared, with Cd close to 1 for a cylinder hit at normal angle, plus more for the drops, but not counting where the hands are. Wind hitting the drops isn't at normal incidence, so Cd will be a bit lower. Still, it's not too far off from what you stated.

The challenge is the rider drafts behind the bars, to the incremental cost of aerobars is less than this. For example, if the wind hits the bars then is accelerated to v (bike speed), but only decelerates to 70% of v by the time hit hits the rider, then that's only half the kinetic energy (and half the drag) of that same air hitting the rider than would have been had the bars not been there. So that would halve the incremental effect of bars when a rider is present. I realize this is an insanely simplified view of wind resistance, but the effect is still real.

Where are you getting prices from? It seems like these bikes are not showing in the cervelo site

9w faster than the S5~P4 which is ~3w from the P5-6 so 6w faster? Something seems off.

I'd totally kill for a P5/p6 with a 2cm reduction in stack.

There are a lot of unknowns in there (for us on the outside) so it doesn't really stack up to compute a 6w advantage. However - it does imply that things are getting close enough that it would be very interesting to see evidence the trickery of the P5-Six is actually necessary.

What is the margin for error in these kinds of reports? I seem to remember that 5-6 aero watts was the common error estimate.

Pretty big margin of error when part of it is hearsay "S5 roughly equal to P4 when bar height the same" is not a basis for detailed analysis.
It's just interesting when the old S5 was so good and they're stating significant improvements to frameset.

http://biketechreview.com/performance/testing/463-wind-tunnel-uncertainty


Shows Texas to have repeatability ~1.5w @50kph

no idea what the 'margin of error is'..all i know is that i've had wood for two days now ever since clicking on the homepage review of the new S5.
Ya think its normal ..or at least OK...for a grown man (with a hottie for a wife incidently) to be this aroused by a freakin bike?!!?::))

Hope to be riding the new S5 next summer! BooYA!!




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BikeRadar reports the new S5 saves "21.3 watts at 40 kph". If the watt savings were reported for the frame @ 40 kph, and the handlebars were reported to save 4.4 watts, then perhaps the bar savings were also at 40 kph, which then scales to 7.7 watts @ 30 mph, which compares better with Zipp's claim of 6.4 watts at 30 mph.

It wouldn't make sense Cervelo would do a bar which wasn't as good as Zipps.

Just on my way back from Euro bike, have time for a few replies.

- 25C front and rear (the biggest 25C we measured was 28.67 mm)
- Completely new fork, similar but not the same as the S3's
- I like the paint too. :-)

Cheers,

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

Hi Fleck,

yeah, Phil's custom painted S5 VWD is verrrry niiiice. :-)

Cheers,

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

Hi burning,

Correct, the 21.3 Watt savings is for the new complete S5 versus the old complete S5. Frameset is about the same (no small feat given we widened a bunch of tubes to increase stiffness), with the bar and wheels making the difference.

Cheers,

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

Frame is the same weight as the S5 VWD. We weighed one at 1065 grams (size 56cm, with paint & small parts).

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