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  1. #1
    bac
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    Jan aero position on the TT bike

    Did Lance's dehydration really lead to his 90+ second loss to Jan in the first long TT on this year's tour? Perhaps it played a roll. Perhaps the air-conditioned tent that Jan used helped him in terms of keeping fluid inside his body on such a brutally hot day.

    Perhaps.

    However, I will submit that Jan's aerodynamic position on his TT steed had something to do with this dramatic win. Look @ the distance between the top of Jan's wheel and his bars compared to the other contenders, including Lance. Look @ where Jan's hands are compared to others. Jan is just WAY lower in the front which has to lead to more speed given the same power output.

    This is why I think that Jan will beat Lance in the final TT - by how much is the real question.

    Has anyone else noticed this? Talk to me!!!

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    bac
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    Jan's position - look where his hands and bars are in relation to his front wheel:

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    bac
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    Now look @ Lance:

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    bac
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    Lance was certainly dehydrated though!

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    7 inch Weagle skdsl's Avatar
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    In the first pic you posted of Lance, he's not even using his aero bars so of course he's higher. The second pic his back is alot flatter.

    I would say that dehydration would be a major factor in speed, so to only lose 90 seconds is pretty amazing.

    And what's with Jan's hand position? Looks painfull to me.
    05 Rocky Mountain ETS-X50 05 Ironhorse 7Point5 04 Ironhorse Glory Townsville Rockwheelers

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    On Your Right ZackJones's Avatar
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    What I see when I look at Jan's position is a huge pocket of resistance to overcome. Obviously JU has the strength to overcome it With Lances arm's up position the pocket isn't as large. With as many hours as Lance has spent in the wind tunnel I think he has the best position he can achive.

    Zack
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    bac
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    Originally posted by skdsl
    [B]In the first pic you posted of Lance, he's not even using his aero bars so of course he's higher.
    Right, but my point with these photos is not to compare body positions, it's to compare handlebar positions as they relate to a constant - like the front wheel. Sorry if I wasn't clear.

  8. #8
    bac
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    Originally posted by ZackJones
    With as many hours as Lance has spent in the wind tunnel I think he has the best position he can achive.
    Right, so perhaps he cannot achieve as low of a front position as Jan?

    Talk to me folks. I'm trying to somehow relieve my anxiety for Saturday!!

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    Look at how Hugh Jan is compared to Lance.
    Moire frontal area = more power needed to force yourself through the air.

    Jan may be lower but thats because he need to reduce his frontal area more than lance. Power output suffers as a result. Lance position on the bike is oriented more towards power than outright low drag Cd.

    Look at Indurain on the bike. He also sat more upright but he was a narrower physique than Ullrich.

    The game is power vs drag. Ullrich won because he coul produce power more consistently than Lance. Lance was dehydrated, not enough medium for his bodily chemical reactions to take place and liberate the stored energy. Not enough energy = not enough power. Not enough power = 1min and 36 secs lossi n a TT. Ullrich's position on the bike had nothing to do with his win.
    An ounce off the wheels is worth 3 off the frame

  10. #10
    Sneaky Slow pgreene's Avatar
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    with all the work lance does in the windtunnel, and with all the special parts (i.e. helmet, bars, etc) designed for him, i find it hard to believe his actual aero position (not the pic you've got of him on the tops-that's on the climb) is the most efficient aero position possible. lance has a different back shape than jan, therefore necessitating a different position on the bike. i think he lost that time because a) jan rode his butt off and 2) he lost 13% of his body weight that day.

  11. #11
    Bring the tech Ajay213's Avatar
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    John Cobb (the USPS aero guy, who spends all those hours in the wind tunnel) stated that the position JU is in works GREAT....when there is nobody on the bike. So the bike itself has a pretty good advantage, but when you put a rider on the bike that advantage goes away. I doubt Bianchi has anywhere near the budget Postal does, and certainly in the amount of time they had to put the team together they certainly couldn't have spent much time on wind tunnel testing.

    Look at that big pocket of his chest, that's really bad. Look how far apart his elbows are, that is catching a ton of wind. Find a picture of LA on the bike properly and you'll see his elbows are much closer together. Jan is just an amazing time trial guy, one of the best in the world with an amazing amount of power.

    Here's a thread where he's talking about it;
    http://www.bicyclesports.com/forum/S...px?PostID=1732

    For Saturday, I'd say JU will win the TT, but Lance won't make the same mistake as he did the other day, you could see LA was dehydrated (anybody catch the white dried junk around his mouth), but I think LA won't loose much of the 1min+ advantage he has now. LA can do some amazing things when he's under pressure.

    Andrew

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    Senior Member Piratello's Avatar
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    Janīs position is perfect and couldnīt get any better.
    Lance instead sitīs more upright.
    - Advantage Ullrich.

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    I guess I'll have to go back to uni and relearn my Vehicle dynamics.
    Clearly the laws have changed...
    I alwats thought it was power vs drag. I guess it must only be drag then

    which ullrich generates more of......
    An ounce off the wheels is worth 3 off the frame

  14. #14
    Bring the tech Ajay213's Avatar
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    Janīs position is perfect and couldnīt get any better.
    Lance instead sitīs more upright.
    - Advantage Ullrich.
    Based on what? How did you come to this conclusion? Just as Tim said in his post there are two pieces to this puzzle, power and drag. Jan could put himself into a super-aero position, but it would reduce his power output to the point that us mere mortals could out race him. That obviously doesn't work. He's better off sitting more upright and using those big legs to power him through the air. His handlebars don't work according to a number of people who have looked at them (look at all the big triatheletes, big-name TT bar makers, etc, none of them make a bar like that and they all have wind tunnel experience) and that he is killing his wrists by holding them like that.

    He's also loosing time by not using a 3-spoke wheel on the front of his bike. But the differences here are in mere seconds over the course of a 40-50k TT.

    Andrew

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    Senior Member Piratello's Avatar
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    just have a look at their backs. Ullrich is extremely bended and flexible in addition he powers a higher gear. The profile of saturdays TT-stage is absolutely flat, so, in my opinion, Ullrich will be in the better position.
    But 1:07 will be difficult...

  16. #16
    Forum Admin lotek's Avatar
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    Bac,

    To return to your original question, if Lance really did
    lose 15#s due to dehydration during the first TT then
    yes it would account for a large portion of the time he
    lost to Jan.
    I don't think that Jan is gonna do it this time,
    he said in an interview with Frankie he got lucky
    on the first TT.

    Marty
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  17. #17
    Senior Member Piratello's Avatar
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    ... and Ullrich is a bit larger (his legs are longer - better lever) than Armstrong.
    This is what I think and what I heard.
    Jan is not one of the best TT-rider without any reason...

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    based on the shape of their backs!!??
    Heckman where did you study aerodynamics, I'd like to know so I can avoid that college!
    An ounce off the wheels is worth 3 off the frame

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    Senior Member Piratello's Avatar
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    the more you are bended (the smaller you are), the less surface the wind will have, or not ?
    The result is that you can ride faster.

  20. #20
    Bring the tech Ajay213's Avatar
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    There is no doubt that Jan has a huge amount of power available to him. But so does Lance. As far as aero goes, there are certain positions that are better than others. But look at that HUGE amount chest of his that is exposed right at the front, that is a big problem and will more than overcome any difference in back shape by a LONG way. The flatter you become on the bike the less power you will be able to transfer to your pedals (lay as flat as you can on your bike, lay your chest down on your handlebars and try and pedal, you are super aero, but of course you can't turn your pedals can you), so you have to compromise. This is why the "ideal" LA position is fairly upright, with his arms fairly close together (to avoid the problem of having that big chest hitting the air), his legs almost rubbing the top tube, and his head straight ahead. LA and USPS have spent probably a couple hundred hours in the wind tunnel in the past 5 years, if they haven't found the ideal position by now, they never will.

    Andrew

  21. #21
    Senior Member Piratello's Avatar
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    Telekom and now Bianchi surely will have spent the same time in the tunnel.
    I donīt believe that USPS has more scientific insights than other pro cycling teams.
    How can Ullrich push those high gears if heīs sitting too "flat" ?

  22. #22
    Bring the tech Ajay213's Avatar
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    Why would Bianchi have spent so much time in the wind tunnel? It's a new team that was formed only months before the tour? USPS has been in the wind tunnel for the past 5 years, that's a HUGE difference. Besides team Bianchi isn't even riding Bianchi bikes for the TT - http://www.walser-cycles.ch/indexx.htm look familiar, specifically the Model 3? Sure maybe Telekom and Once have probably spent some time in the wind tunnel, unfortunatly JU hasn't been with Telekom for a couple of years.

    And how can JU push big gears in a bad position, the guy has got a ton of strength, if he had the "perfect" position it would probably mean a few more seconds over the course of a 40-50k TT. Just simply getting rid of his spoked front wheel and going to a 3 spoke HED would probably get him an extra 5+ seconds on that TT (a few people have measured wheels, and the 3 spoke HED is always at the top by a good margin, except for discs). The real truth is going to come on Sat, hopefully both riders will be at 100% and we can truly see how they compete.

    Andrew

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    each rider will try a position that balances the Powe vs drag relationship. But by far the most significant factor is the power output.
    We can safely assume that Lance and jan have similar power to mass ratios;

    Their power vs drag tarde offs should produce similar times over the same course if their power vs mass vs drag are similar. So what factor then contributed to Lance being over 1:30 down.
    Like he said, His engine was'nt producing enough power because not enough fuel (short cahin fats and sugars) was getting to the combustion chamber (muscle fibre cells) to drive the pistons (legs).

    jan's position on his bike is a fixed known quantity. The only difference was power output.
    I hope it's clear and not to technical.
    An ounce off the wheels is worth 3 off the frame

  24. #24
    Senior Member Piratello's Avatar
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    two nice pics I found:

  25. #25
    Senior Member Piratello's Avatar
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    2nd:

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