New tire diameters!

Me and my friend got new tires. I got small rims and thin sport tires. He simply got bigger tires. Mine are definately smaller then my stock tires and his are definately larger. What does this do to our performance? Will his bigger tires out perform mine or mine be better then his? Also what does this do to our speed? Like does it make my speedometer read faster then i'm going and his slower?

We both have rangers. 98 and 99 models both with 2.5l inline 4 engines. my 98 is a stick and his 99 is automatic. THANKS I really appreciate feedback.

I've got tires on my ranger that are definately bigger than stock. My speedometer says that I am going slower than what I really am. On the interstate up here, I was able to push it up to about 80 MpH. However, a buddy of mine who is a state trooper told me that he clocked me going almost 90. My speedometer only goes up to 85. Hope this helps.

All other things being equal..

Smaller diameter tires: quicker acceleration, lower top-end speed. Speedometer off (reads faster than reality = road rage incident)

Larger diameter tires: higher top-end speed, slower acceleration. Speedometer off (reads slower than reality = speeding tickets)

Both: odometer gives false record = jail/fine if not disclosed at sale.

If the diameter differences are small, it is unlikely you will detect much seat-of-the-pants difference.

Go by a tranny shop and have them match the speedometer to the tires/wheels. This should be a fairly cheap fix.

Thanks everyone, appreciate the feedback.