Outer Limits 4x4 Board

this is probably an old thread, but i was wondering:

1. how do i find out the width of my rims
2. whats the widest tyre i can put on my rims
3. a chart of rim width in relation to tyre width.

e.g.: i want 33x12.5x15 can i fit them on my rims that currently have 10.5 inch width simex on them?

cheers mick

Rims, if they're alloys, should have the diameter/width information in the casting somewhere, i.e. "15x7JJ" which means they're 15" diameter, 7" wide, and "JJ" defines the type of bead seat it has. Steel wheels, hard to say.

As for sizing, figure a 6" wide wheel is good for up to 265mm or 10.50" wide, 7" wheel is good for 285mm 11.50" wide, though the tire makers generally err on the conservative side and would say those are both about an inch too wide. You'll find "recommended" wheel widths in the charts for most tires.
That said, I know a few people running 33x12.50 tires on 15x7 wheels with no problems, though I think that's pressing your luck a bit. I'd suggest an 8" wide wheel for that. I myself run 32x11.50 BFG AT K/Os on 15x7 and got nearly 70,000 miles from my first set.

From what I've seen 16x7 will allow up to 265mm wide and 16x8 up to 305mm generally in a radial. Bias may be a slightly different ball game, and there are tyre exceptions as usual.

running 33x12.5s on 15x7's no worries, fitted them myself with leavers and a mallet, keep them pumped up well so they dont bagg out so much and everythin should be fine!

Theres a difference between fitting and fitting legally.

12.5" tyres need an 8" rim legally, and interestingly I dont think any 12.5" wide BFGoodrich can be used on the road at all in NSW, as they require a minimum of an 8.5" rim!

BFG muddy specs

Cooper muddy specs

And i was lookin @ my swampers the other day...
16x8 rim..

with 36x13x16 swampers... on the tyre states to be put on a 16x10 rim

TOM

From what I've recently heard the bias ply tyres are a different kettle of fish to the radials because they don't have the steel belt in the carcass. If you look at the Simex range for example, the ET's which measure about 305mm wide still go onto a 7" rim. My JT2's in a 10.5 width also recommend 8.5", though they run on 7's ok and within spec.

cool... i have 15x7 rims and am i was looking at the tyres on a 4x4 store website and JTII 34x11.5x15 are about $315.00 and thats exactly what i want, but i didnt want to have to buy new rims. cool as.

thanks guys

Back when i was a grease monkey doing rego's, the basic rule was the rim had to be not more than an inch wider or taller. It didn't matter what size tyre was on it as long as it never came in contact with any vehicle component throughout its travel or stuck out past the outermost edge of the guard/mudflap in a straight ahead position.

But knowing the RTA this has probably all changed in the last 5 years. Especially considering most rice rockets can be fitted with something like 22-24 inch rims and insertion rubber for tyres these days. They probably have had to enforce their rim sizes better.

I doubt you will have any dramas legal wise with 7" rims and 11.5 tyres. Its not an extreme size difference to worry about. The only drama I could see is 34 inch bit. Its bordering on cop magnet size.