tire and rim sizes

PaNsyBoy8

Golden Member
Jul 19, 2001
1,446
0
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What do the numers on tires mean? I like have an idea but i'm still not exactly sure. I'm asking because, i'm lookin into getting some new tires for my car, the tires i currently have are 215/45/17 and I saw someone selling 215/40/17, do you think they will fit? Thanks.
 

notfred

Lifer
Feb 12, 2001
38,241
4
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215 <- width of the tire, in milimeters
45 <- height of the sidewall, as a percentage of the width above.
17 <- the size (in inches) of the rim that the tire fits on.

If you get the 215/40/17s, they will fit on the rim, but they will be slightly smaller than your current tires, and will therefore make your speedometer read slightly faster than you're actually going.
 

RobSan

Member
Oct 11, 1999
178
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215 is width of tire in mm, 45 is the aspect ratio (width to sidewall height) and 17 is wheel diameter in inches. The "40" aspect tire will fit but is smaller in diameter so you will be turning the wheels faster and your speedo will be off a bit. Try a wider tire at "40" or a larger wheel diameter and smaller aspect ratio. Learn to do the math while you're at it.