I'm sort of a car newb and i always wondered what all the numberson the tires meant. For example the cl tires 215/50/17. i know the 17 means rim size. but what do all the other numbers mean?

 

The first number (215) refers to the tread width in mm. The second number is the height of the sidewall expressed as a percentage of the tread width. In this case, the height of the sidewall is 50% or approx 107 mm tall.

 

215 is 215mm tire tread width. 50 is the aspect ratio mean 50% of the 215mm is side wall of the tire.

more info is here: http://www.tirerack.com/tires/tiretech/general/size.htm