Tire questions

[SR240DET]

sorry if this is a stupid question... but what do these numbers stand for?? im just wondering for future references when i look for tires and rims 215/40R17.... thanks guys...

[ca18guy]

215/40R17

215= width of tire
40=   size of sidewall of tire
R=     speed rating of tire
17=   diameter of rim it will fit


The size's are in MlliMeter

Anyone correct me if i'm wrong.

[240meowth]

the last number 17 is not in mm, it's in inch