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Tyer Sizes, What is what??

Posted: Tue Jun 17, 2008 9:55 am
by Remydog05
Ive just spent about and hour looking thru the Bible and havent found much on this but here go's!

What matches what??

EG

315=35? Or is it a 305?

285=32.5?

245=31??

etc, etc

Please add!

Posted: Tue Jun 17, 2008 10:07 am
by dogbreath_48
Take this example: 315/75R16

315 is the section width in mm

75 is the profile, given as a percentage of the width
i.e. 315x.75=236.25mm (sidewall height)

16 is the rim size, in inches (16" = 406.4mm)

So to find the total diameter,

2(315x.75) + 406.4 = 878.9mm = 34.6"

But you're best off looking at manufacturers specs - what's stamped on the tyre isn't necessarily accurate. (e.g. a mickey T MTZ 305 is wider than a 315)

Posted: Tue Jun 17, 2008 10:42 am
by bazzle