ollylovesjeeps

Hi guys my 97' XJ has standard tires etc but on the rear it has 215 75 r15 and on the front it has 215 100s r15 . Are these tires compatible . I would have thought the rear size tires would have also been in the front . Cheers guys

dpace7XJ

Well, im runnin different widths front and back....ive never had an issue...but i'm sure its not "recommended" but it works!! Although i have my wider ones in back....

ollylovesjeeps

Thanks for the info. Are these tires the same width, 215, or does the 100s mean they are different some how.

dpace7XJ

Im not 100% sure but i think the 100 means wider than the 75, but i could be wrong...pretty sure the 215 is height and 100 is width and 15 is rim size, im used to 35X12.50R15 layout haha...someone bash me if im wrong!!

Kyle 4x4 4life

Nope you got it right. always goes height, width then rim size. So say you have the 35x12.5R16 would read 315x75R16.

dpace7XJ

Thought so, good to know!! Thanks!

Kyle 4x4 4life

Yep no problem.

jcwclm

No actually your wrong. In metric, first number is "width", second is "height", and third is rim diameter.

wildbill1

Looking at 215/75/15, I believe the first number is the width in milimeters, 215mm in this case, the second number is the aspect ratio, in "75" for example, the sidewall height is 75% of the tread width. The third number, 15 in this case, is the wheel diameter.

ollylovesjeeps

Thanks for that guys. As long as the fronts don't go round faster than the rears that's good. Cheers

Kyle 4x4 4life

Ok im the idiot.lol

jcwclm

Don't worry, 90% of people think the same thing. I used to, until I started working with tires.

jcwclm

Wait what? You need to get them changed or never put it in 4wd (assuming it is).

Kyle 4x4 4life

Ok i dont feel so stupid now.lol But i just figured the biggest number would mean the height because its the highest number and the middle number is lower so i figured that was width.

Hoooper

I had a short conversation the other day with someone who was adamant that 315 was a 35" tire. It was all I could take to not ask them to run the calcs for a 315/40 15 and a 315/75 15 and show me they were the same height. lol. but seems like a lot of people dont know what it means. Doesnt help that its kind of a dumb systems, the imperial tire size system makes way more sense.

PS: you have 27.7" tires in the rear and ~32" tires in the front, doesnt your jeep lean like crazy? Im not sure i trust that 215/100, ive never heard of a 32x8.5 tire, must look ridiculous