Leipheimer TT position or Cancellara TT position: which is better?
 

As the season approaches I realize I can close up the gap in my TT position so it resembles more of a Leipheimer position than that of Tony Martin or Cancellara. I included a photo of Millar b/c he's sort of in-between. For me, it's just a question of going with up-turned aerobars and I can get close to the Leipheimer position without any loss of comfort.

I'm making the assumption that the "closed" Leipheimer position produces a better aerodynamic profile -- e.g. the wind encounters a single mass and glides around it. The Martin/Cancellara position seems to invite the wind in between the arms where it bounces off the rider's quads and mid-section. The only way I can test is via downhill coast and I will try this soon. If the Leipheimer position is superior, why don't riders like Martin and Cancellara close the gap more? I realize Cancellara would win most TTs on a huffy mtb, but still, why not work on the position?

Thanks

Leipheimer closed gap:

http://www.pezcyclingnews.com/photos...preview-tt.jpg


David Millar medium sized gap reduced with upturned aerobars:

http://cdn3.media.cyclingnews.future...la_529_600.jpg

Tony Martin big gap:

http://www.roadcycling.com/artman2/u...ips_2010_1.jpg


Cancellara big gap:

http://www.cyclingfans.net/images/20..._victory1a.jpg

For those guys to close the gap they'd need arms as short as Leipheimer's.

No one position is better. It is power to cda that matters. There is a balance point between power production and aggressive position that you have to find. Also, the optimal position has a lot to do with your body type. Fabian may have huge drag numbers in using Levi's position. Generally speaking trying to get your head position correct will have the biggest influence on drag.

I imagine they work on the positions quite a bit. There's probably a point of diminishing returns between aero and breathing efficiently. My guess is they're right on the cusp of that in their positions.

my half-assed guess would be the optimization of power production vs CdA. Leipheimer is a small guy, maybe 135 lbs dripping wet. He needs to minimize his CdA, and if he pays by losing 20 W, so be it. Cancellara has 45 lbs on Levi, and assuming his ftp is 6.4w/kg (which is what world record holders put out), that's 280 watts right there. In his case, it may be better to get more watts out and pay a little more price in CdA. That scrunched-up position of Leipheimer sure doesn't look very comfortable.

Edit: got ninjaed thrice over...

Can you expand on this? Is the idea that aero-helmeted head, positioned properly, will have the largest impact on aero profile even if the rest of the body is not necessarily positioned in an aero manner?

Those bigger guys also have longer legs. If Cancellara was squished down, he'd be kneeing himself in the chest. Martin and Cancellara also look to have a flatter back. That may help with their aerodynamics. Levi's helmet isn't flat against his back. Levi also looks to be really compressing his diaphram. You need range of motion and the ability to breathe well to put out enough power. Like others have said, perhaps any power loss on Levi's end due to position is outweighed by his aerodynamics. That probably wouldn't be the case for the bigger guys.

Leipheimer's position is probably superior if you're testing coasting downhill. The question is whether you can sit like that and pedal hard on roads that aren't downhill.

This makes sense. The TTs I'm doing this season are 30k max, most 20k, some 10k so I can handle some discomfort if it means better times at the finish line. I'm a smaller guy with shorter legs as well. I'll try and post a picture of my position. I'm definitely not as squished up as Leipheimer.

I wouldn't do this when it comes to the aerodynamics of TT positions. The reality is, you won't know without extensive field testing, and even then, that's only at 0 yaw. There are too many things that interact with each other when it comes to TT positions that there is never a blanket answer to what is "best." The real answer is, "It depends..." Queerpunk is also correct, Levi has T-rex arms, which helps him create that "egg" position.

Oh, and practice holding your position, whichever you decide on. For instance, if you decide on Levi's arm position, be sure to practice it. Levi even practices it while eating.

http://farm6.static.flickr.com/5096/...2063dbd9e7.jpg

^^ That's ridiculous ^^

i think overall height (head) is more important that the "gap" between arms/head.

Do you mean head position -- looking straight ahead versus head tilted down a bit?

Looking down, or a "tail up" position is often faster because is reduces your frontal area (your head become in line with your body). But, typically you want to "turtle" your head so that you can get your head inline with your body, but still be able to look up the road.

Frontal area is critical. All of their chest/stomachs are parallel to the ground presenting a smaller area to the wind. Backs are all different based on genetics. Armstrong has the huge hump but if you look at his chest...totally parallel to the ground. They're also focusing more on the gap between their arms they're calling the box. Mine has a bus in it.

Look closely: Levi has his head down. At this moment in time, he can't even see where he's going. The others have their heads up. If Levi looked up the road like they were doing when the photo was taken, he'd have an "open gap" too.

Granted, it may not be as much as them, but he's all of--what?--5 feet 3 inches? Compared to them being close to--or over--6 feet tall.

In the end, it's a balance between aerodynamics and power production where power production can be hampered by too tight of a position, making it energy-inefficient, reducing the aerodynamic benefits.

45lb is not 280W

duh.

the math's a little off, the 6.4 w/kg is kilograms not pounds. So it would be 131 watts.

That was a temporary set up That LA used while he was trying out the Adamo. He later switched back to a Bontrager saddle and he wasn't even close to being parallel to the ground with his chest then. But I suspect he was trying to focus on making more power, like his 2005 set up.

http://bikeforums.net/attachment.php...hmentid=190103

http://ttbikefit.com/blog/wp-content...rms-62flip.jpg
And his 2009 set up at ToC was just awful IMO.

Anyways, to the OP - If it were me, I wouldn't go hands up unless I did a lot of testing. I put a fair amount of research into trying to figure out when a hands up position would work (body type, helmet shape, shoulder shape, back exposure, etc), looking at years of tunnel data. I also had quite a few discussions with John Cobb and even thought I had it figured out. So, Cobb and I tested it during a trip last year. Let's just say I've given up trying to predict positional drag based on someone elses results. You just don't know unless you go to the tunnel.

http://farm5.static.flickr.com/4076/...1ffd2a24bd.jpg

To quote Cobb:
" I’ve been working for over a year on how to know when to recommend to a rider that the “hands high” position might work. I’ve tested many riders of different shapes to develop a good working knowledge base, I still will say for certain, that if there is any doubt, keep the lower hand height because when high hands don’t work, they really, really don’t work. When high hands work however, they are faster by a bunch."

Correct, that being said, I dont think Cancellara is at 6.4 w/kg otherwise we would be able to climb with Clenbuterolero or Andy Schleck because if you take 3 riders at the same w/kg they should be able to go at the same speed.

My guess is Cancellara is more about 6 w/kg. He got about 40lb on Contador therefore he can produce more raw power at the same time he has to carry the extra weight and his bigger body is less aero. He got 20-25% extra weight over Contador or Andy S but he does not have 20-25% extra power over them.

After all he is winning those TT by seconds or 1:02 in 1h race (WC TT) where he won by about 2%.

Thanks for the info. I guess my point wasn't Lance in particular. The guys I've looked at, the group at the top + Lance, appear to keep their chests parallel. Trying to keep your back straight just isn't practical and I don't make that one of my goals. First goal is to get rid of the gut. Second is try to adjust my position to reduce my substantial frontal area and getting my chest parallel is one of many factors.

On Lance, I think he dropped Watts being that low. In one of his videos he talked about how Levi can get so low and how really fast TTers look right in front of their wheel and he couldn't ride that way. I took that to mean he was only willing to do so much to his position.

Speaking of wind tunnel, I already told my wife that's what I want for my b-day present. Cheers.

opps, i thought 250W sounded a bit high. FWIW, Cancellara beat both Leipheimer and Pistolero in the olympic time trial in Beijing. That course was by no means flat.

I bet that Levi's position is better for Levi and Fabian's position is better for Fabian. I have no idea what is your optimal position. Try a bunch of different things yourself.

You mean like this?
http://www.slowtwitch.com/articles/i...ium_LeviL5.jpg