tyre size information

copied from a website so people can understand how the xxx/xx Rxx is worked out

Size Coding Revealed
A tyre is referenced as"185/60R/15H", here is an explanation.
A/B/C

http://www.driverstechnologyassociat...re_diagram.gif

A = Width of Tyre (mm)
In this example it shows that the tyre is 185mm wide.
B = Profile as a % of width.
(i.e. profile is 60% of width)
In this example the ratio is 60%. This works out as 111mm.
C = Diameter of inner rim.
In this example it shows that the rim is 15" in diameter.
From this you can also work out your rolling circumference.
e.g. (2 x B) + C = diameter = d
therefore (2 x 111 = 222) + (15" x 25.4 = 381) = 603mm
circumference = pi x d = 3.142 x 603 = 1895mm

Good stuff :cool46:

I've always wondered though, how is the width measured? Is it from the very end of the tread to the other end? Or from where the sidewall squares off?

Or you can go here:

http://www.wheelsmaster.com/rt_specs.jsp

And compare your current wheel/tyre set up with anything you want - also gives you off set info as well.

Chris

Great piece of info and write up