Tire Size -- What do the Numbers Mean?

kelsorat

Knucklehead Newbie
Joined
Nov 5, 2001
Messages
916
Likes
0
#1
I am curious as to what each number on a tire stands for. I've also noticed a possible difference in dimensions-possible between a tire with given measurement in metric as opposed to standard unit.
Can someone give me the explanation?
 

CaptainObvious

Formally known as RV6Junkie
Damn Yankees
Joined
Jan 8, 2000
Messages
3,331
Likes
1
#2
The current standard is as follows:

The first number given in the tire width in milimeters (100 = 3 15/16" also called a 4.00)
The second number is the aspect ratio; i.e. the height of the tire in relation to its width (a 100/100 tire is as high as it is wide).
The final number is the rim size in inches

so...

a 100/100x19 is 4.00x4.00x19