If I wanted to know where to find industry standard definitions about tires, e.g. treads, sizes, weights, names and definitions (like definition of a tire cover is xxxx; definition of a tire patch is xxxx, treads are yyyy, and steel belted radial means zzzz), where would I look? Thanks in advance.

Tire size is given by a number like P225/50R16.

P means passenger vehicle (T is temporary, C is commercial, LT is light truck, I don’t remember the rest).

225 is the tire width, in millimeters.

50 indicates the sidewall height as a percentage of the width (I don’t know why they do it this way instead of just giving it a height, but they do). In this case it would be 50 percent.

R is radius, so R16 means it fits on 16" rims.

Can’t help you with the rest, sorry.

That’s good so far. Is there a place where all this is written down? I know there’s something for what I’m looking for with regards to electricians and code, and such. I am curious if there is something associated with tires.

I found these Googling under *automobile tires specifications*:

http://www.offroaders.com/tech/AT-MT-Tires/tire-tech.htm

http://www.howstuffworks.com/tire.htm (go through all seven parts)

…and this Googling under *automobile tires construction*:

http://en.wikipedia.org/wiki/Tire

I’m sure much more is available by Googling.

No, R is Radial construction. 16 (all by itself) is the **diameter** (not radius) of the wheel, and thus of the hole in the tire, in inches. So yes, it fits a 16" rim.

Pure racing tires (ie. non DOT-approved) usually have overall diameter in mm as the second number. For example, 245/620/17 (roughly equivalent to 245/40/17).

I guess they do it that way because it is easier to calculate how a specific tire size will affect the final drive ratio.