Is Cav riding same bike as rest of team?

Ron Stuart

andrewjoseph wrote:

Ron Stuart wrote:

Went into this on previous post it's just that the modern so called (marketing bull) aero bikes are a outright nightmare in strong cross winds better off with the old narrow round tube steel bike regards aero in those circumstances. The foil has it's aero dynamics ar8e about face and the seat tube will leak water like a sieve :!: Aero bikes are only aero when the wind is either dead ahead, dead astern or none at all :shock: Good on a closed in velodrome though.

I know deep section wheels give a 'sail' advantage when the wind is from the rear quarter (behind and side), would the frame also give a slight advantage in this manner?

This rear 'sail' factor bonus would be exactly cancelled out when the wind was in the front quarter. The only bonus is that there is less turbulance and therefore drag across the wheel profile with deeper section rims. The sail effect is purely being blown along with an increased profile but as I say it is cancelled completely when the wind is in the front quarter. Also there is so much more to be gained by having the rider in an aero position as long as he can put the power down effectively and also the wearing of fitted cycling kit that isn't blowing around acting as airbrakes.
Why Tom Boonens Omega Pharma-QuickStep team decided to take biddons all the way round the short Team TT in the Tour of Qatar is beyond me, I can understand having a drink before you start but there was no way or chance to drink around the course as they were going eyeballs out. Those biddons on a so called aero roadbikes does more damage than all of the aero quirks that have been so called added and they lost the stage to Garmin by .07 of a sec needless to say Garmin didn't ride with them. :roll:

andrewjoseph

Ron Stuart wrote:

...

This rear 'sail' factor bonus would be exactly cancelled out when the wind was in the front quarter. The only bonus is that there is less turbulance and therefore drag across the wheel profile with deeper section rims. The sail effect is purely being blown along with an increased profile but as I say it is cancelled completely when the wind is in the front quarter...

Of course, I knew that, just testing.... :oops:

EKIMIKE

Ron Stuart wrote:

Why Tom Boonens Omega Pharma-QuickStep team decided to take biddons all the way round the short Team TT in the Tour of Qatar is beyond me, I can understand having a drink before you start but there was no way or chance to drink around the course as they were going eyeballs out. Those biddons on a so called aero roadbikes does more damage than all of the aero quirks that have been so called added and they lost the stage to Garmin by .07 of a sec needless to say Garmin didn't ride with them. :roll:

Taking it you're being ironic/sarcastic about the bottles? Also, it was 7 full seconds, not .07 of a second.

Interestingly the conventional wisdom is that a bottle in the cage is better than just and empty cage. Alot of teams, including Sky had riders/bikes with empty cages in that TTT. I guess Garmin got their mechanics to unscrew all the bottle cages.

You're right on one thing though - it's the rider that counts. That is the position of the rider and what the rider is wearing. The wearing bit is simple: Skinsuit and Helmet. The position bit a more tricky: Low as possible but maintaining power/comfort. An interesting idea we're seeing more is those who cannot get all that low 'fill' the gap between their head and arms by having their extensions set high. Generally seen with the taller guys like Wiggins and Millar. Not necessarily proven in the real world though, like so much of the 'aero' stuff.

NB i know f-all about aerodynamics, i'm just recycling things that can be found by reading around a little. Funnily enough i've never read anything about 'sail' effects. Sounds like hocus pocus to me.

ridgerider

I still reckon he has short legs...

EKIMIKE

As for Cav's bike, it's from the same mould as every other size 50 Pina Dogma. The only custom elements will be/are possibly the carbon used and/or the lay-up of the carbon and then the paint job.

The pic above posted by FF is not Cav's bike either (not sure if it was meant to be??) It's far too big.

Ron Stuart

Yep seven seconds misread sorry Ekimike, regards biddons there only any good for carrying fluids and maybe that’s why the peloton gets rid of them shortly before the last few kms of a normal bunch finish.
There are two basic types of "sail effect"
1). Being blown along with the wind by projecting a large area of sail across it this result in speeds less than that of the wind because of drag produced by the hull in the water.
2). Being lifted into the low pressure area of an aerofoil shape (birds wing) where the air on one side has to accelerate relative to the shorter underside that travels at a slower speed, this slower speed can be produced by the bunching up of air inside the conventional sail plan. This only works as long as there is no flow separation the equivalent of a stalling effect. This with the addition of an underwater foil (lateral resistance) enables sail boats to sail upwind (at a degree towards the wind), it also enables boats to sail across the wind at speeds in excess of the winds speed, especially when the boats ride up on to their bow wave and plane like a motor boat with its bow up.
Back to wheels and as you can imagine with the wind coming from the rear quarter as previously suggested any assistance the wind may provide would be would be to the rear end of the wheel that is spinning and the flow require to produce lift in the direction of travel would be from the thick end (tyre bit) to the thin end (where spokes protrude) this would be the equivalent of a bird without altering its wing position flying backwards. The only advantage say a full disc has is to smooth out the flow of wind when projected forward and cut down on drag similar to a skin suit verses a baggy yellow jacket part undone.
Interesting you mentioning about arms though, I overheard Magnus Backstedt correcting Dave Harmon about being on the drops as being the 'most aero'. Magnus said that the Garmin Cervelo team had done wind tunnel tests and it was found that as long as you kept your head as low as it would be on the drops then being on the hoods was seen to be more aero.

spinndrift

I think apart from it being a smaller frame the plain black colour makes it look a lot different shape wise compared to the blue stripes on the rest of the teams.

EKIMIKE

Ron Stuart wrote:

Interesting you mentioning about arms though, I overheard Magnus Backstedt correcting Dave Harmon about being on the drops as being the 'most aero'. Magnus said that the Garmin Cervelo team had done wind tunnel tests and it was found that as long as you kept your head as low as it would be on the drops then being on the hoods was seen to be more aero.

Yeh heard that too. Flat arms, on hoods, in a tuck. Although he didn't really allude to whether it was signigicantly more aero. That's the thing with the whole aero game - they can never produce consistent or real world quantifiable figures.

It amuses me how each different manufacturer has their aero bike as the 'fastest' in their wind tunnel tests. Nor are there enough independent tests to truly verify anything. I guess that's expedient in terms of selling these things to the public though. If they don't know the facts themselves then how the hell are we meant to know? That's where the marketing department do their job and boy are they doing a bloody good job...

Tusher

Cav has tweeted that he's the same height as Peta (presumably when she's in her bare feet) but that he has to move the car seat forward after she's driven it, so yes, he has short legs.

FransJacques

Mad_Malx wrote:

More than just size I think - top tube slopes look very different here:

http://www.letour.fr/PHOTOS/TQA/2012/30 ... T3_019.jpg

Wow that is a terribly unflattering picture, both for the bike and for Cav. Maybe if they put some colour on the frame it wouldn't look like a mini black blob.

Also, having met Cav twice in street clothes, he is skinny, really skinny, athlete skinny. He just has powerful legs. And he's a bit untanned at the moment. Also, Bernie is not a small guy.

Doobz

Wasnt sure where to put this... but.. Robin Williams..

Matt the Tester

nope.

cal_stewart

Doobz wrote:

Wasnt sure where to put this... but.. Robin Williams..

won't lance be hunting him down now he's not on a trek :P

big_p

there's a bit of an article on cav's bike in cycling weekly.

neeb

big p wrote:

there's a bit of an article on cav's bike in cycling weekly.

Yup, they basically say that it is a special compact version, different from the standard team bikes. So it is a custom frame with a top tube that slopes more than on a standard Dogma 2 of the same size. Looks weird because the overall design aesthetic of the dogma has been fiddled around with.

Cav always seems to have a setup with a very low saddle to bars drop, sometimes they look almost level. I guess to get the stem slammed for maximum stiffness and also have plenty standover height for thrashing around in the sprint, a compact design suits him better.

My guess now is that the rumours about cav being reluctant to change bikes when he went to Sky were nothing to do with performance issues as such re: venge vs. dogma, just that he couldn't get a good fit on a standard dogma. Solved by making him this custom version.

Doobz

Seems Sky have a new Rider!

Mad_Malx

Sorry it's a bit late -

I think Cav borrowed the bike from one of the girls in photo 13
http://velonews.competitor.com/2012/03/ ... man_207782

prawny

Doobz wrote:

Seems Sky have a new Rider!

Teen Wolf is looking a bit older now eh.

proto

I'm sure I read somewhere that Robin Williams had a serious Colnago addiction. Maybe a stint in the Betty Ford Clinic has sorted him out.

Ron Stuart

proto wrote:

I'm sure I read somewhere that Robin Williams had a serious Colnago addiction. Maybe a stint in the Betty Ford Clinic has sorted him out.

You may have a point as he was a great Armstrong fan too, kind of fits.

RideOnTime

No tA Doctor wrote:

He's on a bloody BMX.

graeme_s-2

Sky have a feature up on Cav's bike now. It's a Dogma 2 with a customised geometry:

Cavendish is riding a Pinarello Dogma 2 with a special geometry catering for his body shape. In a sloping top tube configuration, it's a nominal 50cm frame with an actual seat tube length of 46cm and a 50cm head tube.

(I assume that means 50cm top tube instead of head tube?)

http://www.teamsky.com/article/1,27290, ... 24,00.html

rick_chasey

Sounds like Merckx in that article.

Nevertheless, Cavendish is asking for changes to his bike position. He “changes his position on a regular basis,” says Blem. “I'd say maybe two or three times per week. Since yesterday he's gone from a 130mm stem to a 120mm and we've just added extra hoods on his bike because he wanted a beefier feel to the handlebars.”

These aren't small changes, “but the thing is, he knows what he wants,” says Blem. “He'll change his saddle up to one and a half centimetres up or down before a 200km stage without a problem. Some riders will feel one millimetre, he can change it by one and a half centimetres.”

Merckx was so picky he'd adjust his saddle mid-decent.