Wheel formula

I know there was a post about this a while ago but I can’t find it…

What is the formula to find the diameter size of a tire using the tires sizing info (ie: 255/75r17)?

redrock4x4.com/tech/tire_cal … hod=metric

Taking the specific tire size you listed as an example:

255 * 0.75 * 2 / 25.4 + 17 = 32.1"

It should be obvious how the 255, 75, and 17 were used in this formula. The 2 is because there is a section of tire above and below the rim and the 25.4 converts from mm to inches.

your factory tires measure 32.05"

I use core4x4club.com/images/tech/tirecalc.htm

you guys rock. Thank you! Trying to decide whether we should go with 33’s or 35’s… just don’t want to open up a can of worms and have to regear or anything…

if your tires are already 32 and change, id say go 35… but thats just my opinion.

oh and i still have your carry along bag. i can drop it off this weekend or Monday depending on when you need it.

I believe you can run 33’s either stock or 1" spacers… 35"s with 2" spacers or 2" lift. The spacer kits are only $175 or less. I’d say 35"s with spacers until your experience warrants a full kit.

Oh wait, you just asked what size your tire were and 4 posts later we’re advising which lift to get :smiley: That’s the way it goes.

refresh my memory… what gears do you have now? Stick or auto? And the 33’s fit with NO lift on 16x8 with 5" backspacing. With your 3/4" lift they fit even better. With my style tube fender flares… you can fit the 35’s with NO lift! I’ve got 4" tube flares and 37’s I can’t bottom them out. Need bigger tires now.