Quote:
Originally Posted by rain dogs
Total threaddrift, but can you give more insight into your calculations?
0.0015 m^2 at 36kmph by my calcuations = 1watt. @ 45kmph it's 2 watts.
I find it hard to believe today's Tour de France pros would be using 28's vs the old school 22's if it was costing them 30ish watts. That's about what some riders would hope to gain with oxygen vector doping.
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How do you figure 1 watt to 2 watts? You think pros are TT on 28 mm tires??
CdA of 0.195 takes about 275 watts for 45 km/h whereas 0.215 m^2 takes about 305 watts. The Cda figure came off the chart. Like I said, I have different wheels and saw a smaller differential at 30 mph and my CdA is a little lower.
Air density Rho (kg/m3) = 1.22601
Crr = 0.004
Rider and bike = 170 lbs
If you look at the previously linked blogpost by Tom A., it shows 5 watts differential at 35 km/h between a 22 and 28 mm tire. It takes a little more work but similar estimations can be seen by Hambini and Flo.
https://www.hambini.com/testing-to-f...icycle-wheels/
https://blog.flocycling.com/aero-whe...-study-part-1/