fat tyres

[salaar]

What's the widest tyre you can fit on a supra without having to roll the arches? I've got a jspec aero, currently with 235/40/18 all round and rims are 9".

[Nic]

265/40R18 would be the widest I'd go on a 9" width wheel, whether they will clear the arches will depend on the wheel offset. Checking with a tape measure should give you an idea of how much clearance you have.

[ellis]

I have 275s on a 10" rim on stock arches. No fouling or rubbing.

[Style]

With the right wheels and offsets, I'd say you could squeeze a 295 or maybe even a 315 tyre under there

[Clausz]

I have a 315 tyre on a 11" wide run without any modifications to fenders:)

 

 

 

[salaar]

you guys got any pictures? 315 sounds ridiculous! Is the offset dictated by the tyre wall size e.g. 30,35,40 etc and also the suspension level? and obviously the arch height.

[David P]

you guys got any pictures? 315 sounds ridiculous! Is the offset dictated by the tyre wall size e.g. 30,35,40 etc and also the suspension level? and obviously the arch height.

 

Have you never heard of Google?

 

There you could find more accurate and comprehensive answers for less button pressing.

[ianhid]

Offset is a strange measurement that makes perfect sense (eventually). It's the distance that the hub mounting face is offset from the exact centre line of the wheel rim. So it varies with rim width but not with the size of the tyre you mount to that rim or the diameter of the rim. You have to find a balance between not sticking too far out towards the arch or hitting the suspension during full range of movement on suspension.

[salaar]

Yeah I thought so but wasn't too sure, thanks a lot. What about clearance from the tyre wall and the arch? Is that dictated by the tyre width? I thought that would be to do with the tyre wall and the suspension, because I'm thinking if you go over a bump, and the tyre is too close to the arch and the suspension is too soft it will hit the arch?

 

So my question is how do you prevent that or calculate that?

 

Appreciate your help, new to the engineering world (physiotherapist (student) by trade)

[ianhid]

Correct, tyre wall to arch clearance is a problem you have to account for. It's all down to the exact size you end up with and whether it's got a little stretch on it or not. Take a tape measure and have a play, also try putting numbers into this http://www.willtheyfit.com/ . Unless you're running a lot of power you don't need massive rear tyres, 265's handle mine at BPU just fine. I get a bit of wheel spin if I boot it but that's half the fun, I'm not drag racing so it doesn't matter.

 

Cost is also worth thinking about. A good 265/35R18 costs ~£130 each, 315/30R18 would be ~£180 each and are not a common size, expect to pay well over £230 if you need one in a hurry. Doesn't seem like much difference but it's a bugger when you get a screw through one.