Larry Colen wrote:
>
>>The behavior I described is the math behind why when someone changes to
>>larger rims and tires (with same overall diameter) acceleration will
>>typically get slower. The new wheel/tire combination is often heavier and
>>even though gearing is the same they will take more power to turn, thus
>>slowing acceleration, and showing lower numbers on the dyno. If you were to
>>put your engine on a dyno and then put the whole car on a chassis dyno, the
>>difference in power ratings is the amount of power being consumed by the
>>driveline in order to turn all of those parts. Lightening, and thereby
>>reducing polar moment, will not make power, but it will give back some of
>>what you already paid for when you built your engine.
>
>
>
> That's not quite correct. Putting on taller tires will give you a
> taller final drive ratio, the car will go further per turn of the
> engine. However since the torque available is the same, X foot pounds
> divided by more feet give you fewer pounds of thrust and therefore
> less acceleration.
>
I think he's right. He's saying larger wheels but with the same
diameter, i.e. lower profile tires. Given the same diameter, would
have the same rotation has stock, thus maintaining the final drive
ratio. But more metal of bigger wheels is going to mean more weight.
Of course, that's a generalization. A 15in aluminum wheel could be
less than the 14in stamped steel Rosytle.
Does anyone know the weight of the Rosytle, and the 14 and 15 in
Minitar's sold by Moss, or the 14 and 15 in Panasports?
What about the weight of wire wheels? Obviously, the new Dayton 72 spoke
wheels is going to weigh more than the old 60 spoke wheels.
Paul.
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