a stupid question

[AOE_Conqueror]

Anyone can tell me what is the meaning of the parameters for the tire

e.g. P155/80R12 SL (FBM)
What do these numbers and letters exactly mean?

Thanks a lot!

 

[月下独酌]

P = Passenger car tire
155 = width of tire
80 = ratio of height to width
R = Radial
12 = wheel diameter in inches

 

[月下独酌]

SL 因该是Speed rating