The horsepower should remain unchanged, however the effective rate of accelleration will change. The larger diameter tyre [increased circumfrence] The effective distance travelled will be longer for 1 revolution. More work would be required to turn the larger diameter tyre at the same rate as a smaller one for one revolution.

I think I got that right. maybe.

Quote:No, but it certainly affects the overall gearing. Larger-diameter tires will make most cars accelerate more slowly.

well on the dyno would it not be the opposite?... because there is a no need for traction because the wheels are turning on the rollers, a heavier larger tyre would actually take more to turn and add wieght, actually taking away from minimal amounts of horsepower...talking about tiny amounts of horsepower.

surely not... or else all the dyno pigs would have custom 10" wheels with low profile tyres.

Hi Guys,

Can tyre size affect rear wheel horsepower?

The basis of the question

If you put a car on a Dyno and perform a run and then chage the tyre size up to a larger overall size, will the rear wheel horsepower change.
excluding the very small fraction of a friction increase by the larger tyres.

Cheers Guys,

A link to proof or actual mathmatical proof for a yes or no answer would be appeciated.