Wheel/tire size calculator

**audi314** · 02-21-2008 03:39 PM

I ran across this calculator. Its pretty in depth. Just thought I would share.

Calculator

**dirtybrd** · 02-21-2008 03:43 PM

Very nice.

**Capt. Obvious** · 02-21-2008 03:48 PM

That one's pretty cool. Nice find.

I usually use these two:

Tire size calculator

Offset calculator

**sixfiveoh** · 02-21-2008 03:52 PM

Jeez. If I went to 17x8"s with 215 tires, my actual speed would be 31.2% faster than my speedo was showing?

That sucks.

**Capt. Obvious** · 02-21-2008 03:58 PM

Depends on the aspect ratio of the sidewall.

**sixfiveoh** · 02-21-2008 04:01 PM

So there's ways to tweak with the dimensions to get smaller margins of change?

**Capt. Obvious** · 02-21-2008 04:39 PM

Correct.

For example, if the tires on your car right now are 225/55/16's, if you went to a 215/50/17 there would only be about a 1% difference.

Using the 225/55/16 as an example:
The first three numbers (225) are the section width of the tire (width at its widest point). The second (55) is the aspect ratio of the sidewall, or the height of the sidewall as a percentage of the section width (the sidewall height is 55% of the width of the tire). The last number (16) is the size of the rim they go on.