I am looking at purchasing new tires and have been looks at the overall tire diameter heights online at the manufacturers websites.

They list an overall tire height (tire diameter) but what exactly are they measuring? Is this before or after the tire is mounted on the rim?

I measured my BFG AT 31x10.5x15 tires they other day and BFG says they have a total diameter of 30.7". I measured my tires and they are only 29.4" or so.

Then i measured my Nitto 325x60x18 Terra Grapplers. Site says 32.9", and they measure pretty close at say 32.7"

Then i just measured a set of pro comp 35x12.5x17 A/Ts... site says 34.9 and they measured 33.75"

IM pretty sure air pressure and wheel width come into play here though as well.


I was just wondering. Im looking at getting new 35" tires and cant decide between:

BFG A/T 325x60x20
Nitto Terras 325x60x20
Toyo M/T 35x12.5x20

I have always been a BFG A/T and like their tire the best simply because they say it measures to 35.5".... but they are the most expensive also- I dont want to go buy they and have them measure to 34.5 though....

Ya, i know im being picky now... hahaha.

 

I found measuring a tire horizontally to be much more acurate than measuring vertically. the weight of either your vehicle will depress the diameter some. try measuring horizontally. From what I have read on here all those tires are good, I myself am partial to BFG's. but they are quite expencive. I almost went with nitto's my second time arround but I like the looks of the Bfg's so much more. plus they are a winter rated tire. I do not think the Nittos are.

 

Tire manufacturers measure tire height with the tire unmounted.