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Old 02-08-2012, 12:56 PM   #148 (permalink)
sendler
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A big tail fin helps a top speed vehicle go straight where the wind speed from the front is always way bigger than the speed of any side wind blast. On a commuter vehicle that is intended to average 70mph, a 30 mph side wind is a considerable amount of the total wind force acting on the motorcycle. For a road motorcycle, I think any added tail fin will be more of a problem than any possible improvement most of the time.
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Quote:
Originally Posted by drmiller100 View Post
another way to look at it. The smarter Bonneville racers understand center of pressure and center of gravity.
The faster you go, the more the center of pressure moves forward.
You ALWAYS want center of gravity in front of center of pressure, or when you get going fast enough, the dynamics of it all will fix themselves until the center of Pressure IS behind the center of gravity (Spin out).

I would think the fin might save you in a really bad spin, but it would be better to move the CG forward and the center of pressure back.

The heaviest thing on a bike is the rider. The second heaviest is the rider. The third heaviest is the engine.

Cafe racers move the riders CG forward.
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