hey how do you tell what tire to use on what size rim? like if its 18 inch rim of course its 18 inch tire but like when a tire is 7.5 wide.. what number on the tire tells what size rim it will fit on?

 

and tirerack.com

And they lived happily ever after. The End.

 

it all depends what u can afford but the best thing is ask the tire shop what's the best for u.. like mine, i got 18's and 7.5 wide and my tires NITTO 235/45/18

 

well what i meant was... if you have a 7.5 width rim how do you kno what kinda tire to buy? i dont understand all 3 of those numbers on the tire size

 

the first # is section width in mm (side wall to side wall), the second number is the side wall, not in mm but as a raito of the section width. The thrid number is oviously the rim size.

Knowing the rim width tells you how wide of a tire you can use. Tire manufactures will have a recomended rim width for each tire. My 245/50/15 Dunlop sp 8000 recomend 7"-9" rim width. Anything smaller and the tire won't fit properly. TireRack or the manufacturers website will supply the specs for the tires.

So when picking a tire you will want to make sure it is approved for your rim width. A 7.5" rim will fit most anything from a 215-245. The side wall height will also impact a wider tires ability to fit on a smaller rim. I can fit 245's on my 7.5 easily since I have 15's and plenty of side wall flex to work with. I probably would not be able to fit a 245 tire on a 18"X7.5" rim though.

If you are not comfortable with all this, just talk to a place like TireRack and they will tell you what size tire to run.