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Home Aerodynamics Wheels Tour de Suisse: Ullrich Wheels

Tour de Suisse: Ullrich Wheels

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Tour de Suisse final TT observation...

While perusing the photo's over at, I noticed something peculiar about Jan Ullrich's wheels.  The rear one in particular.  Check it out here:

[photo link]  [better photo link]

The twist of the spoke indicates that the wheel developer is thinking a bit outside the conventional box, so to speak.  The twist essentially makes the spoke behave as if it is at a slightly higher angle of attack (in the traditional sense of spoke/wheel design -> higher yaw angle). 


editor: 11/08/2005 -> NEWSFLASH!  Tobias Winnemöller emailed us and pointed out that Xentis wheels are not twisted!  Yep, he's right, a fact that we noticed when testing these in the wind tunnel recently - in our laziness we forgot to update this highly speculative blurb.  We sure had a good ol' time writing it up last year, but remember folks, as the byline above clearly states:  THIS IS SPECULATION - surely a PhD candidate knows what that means, right?  ;-)]

The slightly higher angle of incidence might theoretically shift the "sweet spot" of minimum axial force.  This is quite creative, BTW.

Typically, aero wheels generate less axial force (commonly, though, incorrectly referred to as "drag" - read more about this pedantic correction here) when gentle crosswinds/yaw angles are present.  I would speculate that Ullrich's new wheels would do best/(better than possibly any other wheel) in steady winds coming from a preferred direction.

Jan and his team had best be careful when those wheels are used, though, because if the wind shifts a tad bit during the event, odds are those wheels will perform worse than a conventional egg-beater set of wheels!

So what?  Well, at the skinny end of the results, every little bit counts -  and Jan Ullrich might have actually won the Tour de Suisse despite his wheels.  One thing is for certain, though; I'm glad to see that it appears as if some people are still thinking outside the box!

Last Updated on Tuesday, 23 February 2010 04:43