Are 31"tyres bigger than my 265/70/15's??

[bboy02]

Hi guys,
I have a set of 265/70/15's on my surf at the moment. I dont know how to work out the diameter of these tyres from this sizing system. I know that 31x10.5x15 is as big as I can go without lift but I am unsure if this is any bigger than the tyres I have on at the moment!
Many thanks.

[BUSHWHACKER]

They're more or less the same size. 31" tyres were a factory option.

[bboy02]

I found an online converter which puts my tyre diameter at 29.6 inches. Only 1.4 inch difference with the 31's. Do you think that makes a worth while change?

[Slugsie]

I found an online converter which puts my tyre diameter at 29.6 inches. Only 1.4 inch difference with the 31's. Do you think that makes a worth while change?

That depends on you really. 31s are taller, but as you say it's not by much. If you want to go bigger, then you will have to look at lifting your truck first.

[Apache]

Unsurprisingly, a 31" tyre isn't always 31" in diameter. It depends on the manufacturer, and the rim width you put them on. My 265/75-16s were 31.5" in diameter on 8" wide rims, and my 33" Mudzillas on 10" wide rims are 32" in diameter.

[nero279]

theoretically your tyres are 752mm tall, compared to 787.4mm for a 31" tyre.

35mm difference on the diameter = 17mm on the radius = you really ain't gonna notice much.


However, that's theoretical, and has already been said there's variations between tyre makes/models, the rim width affects the final size, so you could find you gain a little more or a little less, i wouldn't bother just for the sake of it, unless they need replacing anyway. Also if/when you do replace bear in mind that generally speaking an MT will come up slightly larger than an AT tyre.

[BushBuster]

Hi. I dunno how to insert a link, but if you got to the thread 'Micky Thompson ATZ' and quote 28 you'll see the answer from 'yoshie' which explains.