70_Nitrous_Eater said:
275 is the amount of millimeters from outside rim mounting surface to inside rim mounting surface. (think of this as tire width...sorta)
60 is the ratio of the 275 width of sidewall rubber to tread rubber. So 60% of the rubber is sidewall, 40% is tread. So an 80 series tire is a taller/skinnier tire and a 30 series is a wider/shorter tire
these two are wrong.
275 is the section width of the tire when inflated on its design rim width. the section width is measured at the widest point of the tire, the center of the sidewall bulge. in the case the section width is 275 millimeters.
60 is the aspect ratio. this tells you how tall the tire is from the bead to the top of the tread, in this case 60% of the section width.
every tire manufacturer uses a slightly different tread width on their tires, so there is no actual measurement of tread width.
there are a few other numbers and letters you need to be aware of;
traction
temprature
treadwear
load index
traction and temprature use an alpha character IE: a b or c
the higher character the better traction or temprature resistance. a is higher than b.
treadwear is indicated by a number, 100-400 generally
the higher the number the longer wearing the tire.
load index tells you how much weight the tire can handle at its rated tire pressure, and at a specified speed, usually at the speed rating of the tire.
the speed rating is usually included in the tire size. example;
275/60R-15 H
the speed rating is not like the others where the higher the better. an H rating is higher then an S rating for example
sometimes the speed rating is included in the load index, example 92H
any tire shop you go to should have all the information you need to decode the numbers on a tire.
amnit:
