so i was surfing the web for new tires and tire information and general, and found this tire calculator. I think it's a really helpful tool. I don't know fi this is old news or anything, but i thought i'd post it up incase no one has seen it

http://www.miata.net/garage/tirecalc.html

you can put in ur tire size, and find all ur dementions without doing all the screwy math, and u can put in old size and new size and find out how off ur speedo will be.

--Jared

 

Repost, but yes, that is the one I usually use to calculate tire sizes/ratios.

 

I made my own Excel spreadsheet so I never have to go find a website calc'r anymore. everytime I need calcs for something on the 4Runner I add it to the same Excel file but on a different worksheet. now it's pretty big and has almost all the calcs I've ever done. you should start one too.

 

This is one I regularly use. It's nice to be able to compare 2 sizes at once:

http://www.wickedbodies.net/Tire-Size-Calculator.htm