Automotive Torque and wheel size of a car

1. Dec 9, 2014

Nick666

So lets assume I have 100 Nm at the wheel of a car, with a wheel size of 25 in diameter

If I put wheels that are 24 in diameter, so 4% smaller, what exactly will change ? Will I have 4% more torque ?

2. Dec 9, 2014

xxChrisxx

Waaat.

You'll have exactly the same amount of torque. Something will change at the contact patch through.

3. Dec 10, 2014

Nick666

Isnt there some formula that might be applied here ? ... F = T*r ? Doesnt a change in wheel size of a car act like a gear change ?

4. Dec 10, 2014

Nick666

Ohhh...its F=T/r ... I get it now.

5. Dec 11, 2014

felmon38

If F is the ground force on the wheel then T- F.r = IG

6. Dec 17, 2014

rsk2mc

Also your rpm changes. The circumference (pi*D) is less on the smaller diameter.

7. Dec 23, 2014

Harshit puri

no you won't have more torque .. torque is a function of gear ratios at wheel torque = engine torque*gear ratios*differential ratio
So when you are considering change in tyre dimensions assume it constant. so for changing wheel selection following things will occur.
in this case your tractive force will increase..