ok so the deal is i have a set of 18 inch wheels with brand new tires, the downfall is one is dented and another is cracked. The tires are brand new and the size is 215/35/r18's. My friend is selling me is 18 inch rims because they need new tires. but the tires he currently has on them is 240/45/r18s. will my tires fit on his rims? thanks

 

No, tires are rated for a certain range of wheel widths.

215/35/18 - rated for 7" - 8.5" wide wheels
245/45/18 - rated for 7.5" - 9" wide wheels

 

will the 215/35/18 tires fit on a 225/40/18?

 

Huh? You cannot put a tire on top of a tire. Like I said before, the wheel width is determined by the tire size.

 

i mean a rim with a 225/40 tire on it. how do you know the tire widths by the numbers? is there some kind of calculation done?

 

What is the actual wheel width he has? Looks like from the post above an 8" wide could work for either,and also 7.5 or 8.5. It should say 18 x W on the rim which is better than a measurement unless you know how/where to mearure.

 

If your friend's wheel is between 7.5" and 8.5" you are fine (as mentioned above). The width of the wheel should be stamped on the back somewhere, so its worth a look before buying

 

The specifications I listed are given by the manufacturers of the tires, as to their regulated limit of wheel width. You need to find out the wheel width, as the tire width really doesn't mean much.

And, where did you get this 225/40 tire? Your story is very inconsistent.

 

sorry the 225/40 are enkies i just bought off craigslist for $380
needed new wheels pretty badly. and ill see how wide they are

 

ok so both rims say 18X7.5 on the back of them so im pretty sure theyll fit