what do the numbers mean?!! im a super noob... ie.: 215/40/17 i think thats what on the stock rims.. i think i know that the last number is the rim size.. correct? can anyone help me?

 

17 is the size of the rims 40 is the maximum/suggested tire presure, and 215, maybe 215 MM thick or maybe maximum speed 215 mph??? i have no freakin idea

 

215 is the tread width in millimeters. 40 refers to the aspect ratio of the sidewall which basically means "the height of the tire is X percent of the width" In this case its 40% or 86mm. The 17 refers to the rim diameter the tire is built for.

 

Generally the bigger the first number, the better grip you're going to receive. For the second number, the higher the number, the taller the tire is going to be. This allows you to lower the pressure down in the tire more. This helps with dig launches (like i drag racing). the last number is the diameter of the rim.

 

HERE is a lengthy tech article describing tire sizing.

 

lol, i tryed my best