Maybe this is a matter of semantics...
True, the motorcycle absolute top speed is limited by drag and HP.
However, for a motorcycle with an top speed limited by gearing or
engine revs then a larger diameter tire will allow for a higher top
speed ALTHOUGH this tip speed may not be the absolute top speed
limited by drag.
For example a 20 hp bike motor that will turn 6000 revs (and
pretending that the tranny is direct drive) will turn the tires 6000
revs. If those are 10 inch circumference tires then the bike will go
speed x,(no, I'm not going to calculate it out.) but if you have 20
inch circumference tires then the bike will go twice as fast *** IF
*** it is not limited by drag and that the engine can turn the 20
inch circumference tires at 6000 revs.
On Oct 21, 2008, at 1:06 PM, Weslake1330@aol.com wrote:
> Not so.
> Top speed is limited by aerodynamic drag and BHP. To go faster
> you need
> less drag or more bhp or both.
> Acceleration on the other hand is limited by lb/f torque to weight
> ratio (to
> the point where the drag is greater than bhp and limits top speed and
> therein acceleration).
> The motorcycle has less drag than a car (less frontal area really)
> so needs
> less bhp to reach its maximum speed. The wheel diameter is neither
> here nor
> their because the gearing controls the gearing and the wheel
> diameter is just
> one factor.
> W e s l a k e 1330
> In a message dated 21/10/2008 18:15:47 GMT Daylight Time,
> is, BHP or HP by any measure really has nothing to do with speed.
> Only in
> elapsed time to reach a given speed. I have seen a 20 HP
> motorcycle reach
> 110 mph because of its wheel diameter and gearing. Likewise, I
> have seen 200
> HP V-8s that couldn't hit 90 MPH.
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