Rim and Tire calculator

[HAULN-SS]

<!-- m --><a class="postlink" href="http://www.rimsntires.com/specspro.jsp">http://www.rimsntires.com/specspro.jsp</a><!-- m -->

This is the best one of these I have seen on the interwebs. Thought someone might want to sticky it

[SlimKlim]

That's pretty awesome if you're trying to figure out wheel offsets and whatnot.

I use this one when shopping for tires, if you happen to have a BMW you can scroll down and load up the gear ratios, or you can enter them manually, and figure out how much of a deviation in diameter you'll get with different tires sizes and how that will affect your gearing.

http://www.endtuning.com/gearratios.html

When I fucked up and put 245/40s on my car instead of 245/35s it would've theoretically done 100mph in 3rd gear. It caused about a 5% decrease in gearing so it was more like the car had a 2.97 diff instead of a 3.15.