It equals a 31 inch tire. For everyone who assumed this size was a 32 inch tire (which i was under the same impression), we were wrong.

Just thought some people would like to know this little bit of info...cause it seems everyone is trying to compare XXX/XX/XX tire size to an equivalent in inches.

i got these tires a couple of weeks ago and measured them when i got them. All four......just barely 31 inches.

Just a little FYI

Try measuring a 31x10.5/15...its typicaly 30.5" or so, the 32x11.5's are about 31.5" or so...so the 265/70/17 is also shy of the nominal equivalent.



In short, tire sizing is not exact, or even always descriptive...for example, some 32" dunlops are 31" in diameter.

gotcha, thanks for the info.

This also varies with tire manufacturer (BFG seems to be pretty bad about it). Go to the manufacturer's site and they usually list the exact height of their tires somewhere.

and for what it's worth, those numbers do mean something

xxx/yy/zz

xxx is the width of the tire tread in mm, zz is the rim size and the sidewall height is (%yy)*xxx

I.E
265/50/15 is a 15" rim, 265mm wide tread, and sidewall height is .50 * 265 mm.

So if you do the math, the 265/70/17 tire equals a 31.6" tall tire.

I believe what really matters is figuring out what speed you are actually doing when you have installed larger tires to prevent being pulled over by the authorities. A 265 70 17 is larger than the 265 65 that was on there. You can calculate all day, but as previously stated, there are differences between manufacturers, so maybe use a GPS or have someone with stock sized tires drive beside you at different speeds to see how fast you are moving.

or theres always this handy tool from the faq

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

besides. Their never exact anyways. After time all tires shrink.

Hmmm. 265/70/17 instead of 265/65/17 makes your speedo read 60 when you're actually doing 62. Not even enough to worry about. Cool tool man!

Not sure if that if that is exactly right, but then again I have compared to other people's car's speedos, I have seens as much as 7 miles per hour difference at an indicated 65.

Good info on the tires...

Rez90, have you noticed any difference in ride since gaining a little higher sidewall? Perhaps a little smoother? I was considering that tire size when my tires are done.

What kind of tires did you buy?

John

my cruise at 65 is 70 on Mr. Policeman's radar with the 265/70/17 BFG's..at least that is what he said when he puleld me over.....

The ride is basically very similar to the rugged trail's that the truck came with......maybe a tiny bit louder. I personally don't push my truck around corners to actually test the sidewall strength.......I usually drive my truck slow and easy......My EVO on the other hand.....Thats another story....i know exactly how stiff the sidewalls are on the tires on that car.

I got BFG AT KO's in 265/70/17....and i know exactly what the #'s mean.....lol

Thanks for the reply! That sounds like a good way to go. You are right, there is no need to push the X into a corner to test the sidewall. Too bad my tires only have 3,000 miles on them...it may be a while.