Thread: Is this size tyre legal for D3 (QLD)

Originally Posted by sheckster

265/60R18 110H (Scorpion STR) (QLD)

thanks

Well, i don't know how to translate the numbers but i'm on 37inch by 12.5 inch by 15 and never had a problem.

I think it is ok, from memory it is now 15mm maximum, so from original (i can take as a guess an SE) 255/60/18 std, to 265 is only 10mm difference.
Someone will chime in with the legalities..

Cheers

I "think" the 15mm rule is for low profile tyres. Have a read of this.....

Originally Posted by sniegy

I think it is ok, from memory it is now 15mm maximum, so from original (i can take as a guess an SE) 255/60/18 std, to 265 is only 10mm difference.
Someone will chime in with the legalities..

Cheers

Not quite as simple as only 10mm difference. 15 mm refers to overall increase in tyre diameter - the difference in overall diameter between a 255/60 and a 265/60 is not 10mm.

255 x 60% = 153mm, then x2 cos there are 2 sidewalls = 306mm
Add in the rim - 18" = 450mm
Total = 756mm total diameter

265 x 60% = 159mm
x 2 = 318
+ Rim (450mm) = 768mm - so 12mm difference, which is within the 15mm.

Note that each manufactures 255/60 R18 will be different to the next - most are not exact, some some may be more than 15mm difference in diameter.

Hope that clears up the way sizes actually work a little bit...

Try this:
Tire size calculator

It saves all the mental arithmetic.

255/60/18 =763mm
265/60/18 =775mm

Whilst the regs are written from the point of view of someone fitting a larger diameter rim but lower profile tyre the +15mm rule is clear and would apply to all.

So 265/60 are fine if you can get them.

Cheers, Steve