John Cobb Interview
Thomas talks to aerodynamics god John Cobb about working with Armstrong and how Ullrich could have saved time in the Tour's first time trial.
in the way the frame is laid up so it has a different feel.
On previous occasions you've commented on the differences in the time trial equipment used by Lance Armstrong and Jan Ullrich. Please describe these differences and let us know how you estimate that these differences affect the performance of the two riders.
Ullrich uses a more "low hands" position that might be working for him but I doubt it. Ullrich obviously has great power but I think his position could be improved by 10% or more. Strong riders have a hard time letting some of the power go so that they can pick up better aero performance but even the best humans are not very good motors so aero really matters.
Ullrich and his team are using cut off aero bars in the Tour while Armstrong opts for a more normal arm/hand position by using regular time trial aerobars. How does this difference affect the performance of the two riders?
I haven't found and aero advantage to the cut off bars yet, I'll keep testing though. Generally if you develop bars without a rider on the bike you might end up that way.
How much time do you estimate that Ullrich could have saved in the first individual time trial of this year's Tour de France by using more regular aerobars (more similar to Armstrong's)?
I think with different hand positioning he could have been 30 sec. faster.
Some riders, including Armstrong, use flat handlebars in time trials, while the handlebars chosen by other riders point downwards. What are the pros and cons of each handlebar type?
Flat bars might feel better for when you're accelerating off a corner or climbing. Sponsorship decides most of that. Either set up will work pretty well.
On a more general note, are there differences in equipment and position between an individual time trial and a team time trial?
I wouldn?t think there would be much difference other than needing to carry more water for the longer team TT.
When using the "Giro Slam" position with Armstrong and other riders, how long does it take the rider to adjust to this extreme aero position?
It takes about 5 minutes to get used to it. It very closely mimics their regular road position.
Is there a compromise between the most aerodynamic position and one that is upright enough to allow for breathing/air entry?
Really aero positions usually hurt breathing performance. Real good low aero positions are real hard for high mileage racers to stay in for very long so their overall drag might not be too good in those positions.
How much faster can an efficient and well trained rider become after refining/improving technique in a wind tunnel?
Over a 40k TT the improvement can be 15?30 sec. for a rider that is already in a good position.
Which is first, a technological advancement then the wind tunnel, or vice versa?
It can go either way. Sometimes a test change and the results will set