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Old 11-23-10 | 02:58 PM
  #24  
gregf83
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From: Vancouver, BC
Originally Posted by DnvrFox
So, does this seem the case with anyone else, and, if I am not the only strange one here, why is that? - I mean that riding into a wind seems harder than a comparable combined speed with no wind. And, yes - I was going about 5 - 8 mph on my mountain bike against a most gusty and obstinate chilly wind for about an hour.
It's the other way around.

Neglecting friction, aero drag is a function of the apparent wind speed. So whether you are travelling 30MPH with no wind or 15MPH into a 15MPH headwind the aero drag or force resisting forward movement is identical.

Since power is equal to aero drag x ground speed, travelling 15MPH into a 15MPH headwind will take 1/2 the power required to ride 30MPH without wind. The drag is the same but in one case you are doing much more work in a given time period.
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