So, lets say my tires are 245/45/19 (something like that), what does each number mean? And on rims what are offsets, and how do you decide which ones to get? sorry for the noob question, im new to the world or rims. sorry if its a repost, i couldnt find anything.

 

The numbers in the tire size refer to its width, aspect ratio, and wheel diameter. "205/55R16" means the tire is 205 mm wide, has an aspect ratio (that is, the width divided by the height) of 55%, and fits on a 16" rim.

"R" means radial tire. They're all radials nowadays. Speed ratings are usually inserted before the "R." The most common speed ratings are HR (good for 130mph), VR (149 mph), and ZR (more than 149 mph).


copied this from http://www.machv.com/whathecdotho.html site.
google does amazing things!

 

What about offsets on rims? and how to you determine what you want?

 

Personal reference pretty much. obvoisly you have to stay in certain guidlines but other than that its what you want.

 

Ok, if im looking to get these: Forgestar Wheels | The Worlds 1st 1 piece lightweight flow formed wheel lineup, 19x9 and 19x10, and im looking for 275 in the back, what exactly do the offsets determine and which would be good for that.

 

example 15x7 offset 35

offset is the number in mm from the center of the wheel. so +35 is 35mm towards the outside of the wheel from the center of the wheel. the center of the wheel is 0. -35 is -35mm towards the inside of the wheel (towards the car). the lower the number, the fatter the lip.

 

Alright, thanks man.

 

Great info on those items here Tech Center