Sunday, February 7, 2010

Aerodynamics on the Bike

I told you in January I'd write a blog on Aerodynamics- so here it is. And yes, there's that silly "Speed Triangle" again. For those of you that are seeing it for the first time..the "Speed Triangle" contains three major parameters responsible for going FAST on a bike: Comfort, Power and Aerodynamics. I briefly discussed Comfort in my January blog, therefore I'm going to talk about another leg of the triangle- Aerodynamics.
It seems to me, that of all of the sides of the "Speed Triangle", most cyclists (and triathletes) are more concerned with Aerodynamics than any other leg. Why is that? Do you really want to know why I think so? Because in addition to aiding in going fast- it's cool. Yes, the "cool factor". And I'm not talking "cool" temperature-wise I'm talking "cool looking". Don't believe me? Go into any bike shop and other than a "cool looking" aero bike ask them what more recreational racers/triathletes/etc. spend their money on. I'll bet you it's a "cool" lightweight aero wheelset. (Seems like nobody has $$ for a $1300 Power Tap but everyone has $$ for a $2000 wheelset.)
In the 2010 Velo News Buyer's Guide, there's a good article on pgs. 16-17 written by Robbie Stout entitled, "Which Aerodynamic Equipment benefits most during the race of truth?" For those of you that don't know, the "race of truth" is a Time Trial...because it's all hiding. In that article there's a chart on p. 17 listing the aerodynamics savings (in seconds) of various equipment/clothes for a 40k (25 mile) Time Trial. I was actually a little surprised at the top savings. Here's a quick summary:
1. Speed Suit- frm normal road bib/jersey to Nike Swift Suit- 134 seconds
2. Body Position- frm upright position on bullhorns to tuck position on aerobars- 122 seconds
3. Aero Helmet- frm road helmet to tear drop helmet- 67 seconds
4. Body Position- frm tuck position on aerobars to tuned wind tunnel tuck position- 56 seconds
5. Front Wheel- frm 3-5 spoke to deep rim 12 spoke- 42 seconds
6. Shoe Covers- from no covers to covers- 30 seconds
7. Rear Wheel- frm Full Disk to 3 spoke- 29 seconds
8. Front Wheel- frm 24 spoke Al box-section rim to 5-spoke- 23 seconds
9. Aero Bike Frame- from std tubing TT bike to Aero tubing TT bike- 17 seconds
10. Aero Helmet- frm tear drop helmet to best Aero helmet- 13 seconds.
What the article didn't list, however, is probably the largest savings..and that is going from riding a road bike in the drops to a Time Trial bike in aero bars. Ready for this- a whopping 5 1/2 minutes savings. That's equivalent to about 60-70 watts of power...which is HUGE! (BTW, the 2. body position listed above is going from an upright position on the bullhorns of a road bike to a tucked position with clip-on aero bars on the same road bike.)
So, if you're a Time Trialer (or wannabe) and you REALLY want to go as fast as you better have a state-of-the-art Time Trial bike ($7k), with the latest aero wheels ($3k), a Nike Swift Skinsuit ($300), the best aero helmet ($300), shoe covers ($50) and a well tuned wind tunnel tested aero body position ($500/hr). If not, you're already racing at a disadvantage. That's the reason why I don't Time Trial local races anymore with my road bike and clip-on aero bars. Why? Because it's not a level playing field I'm competing on. The fastest/faster time trialer (locally) is NOT always the strongest cyclist..perhaps just the richest. Power ON! Coach Rob

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