By any odd chance, does anyone know what tyre size will fit on a j and s buggy with a three inch body lift? Hoping to go 31's and 30's on 15 x 7 inch rims.

Should just about fit on the back as long as it clears your suspension (might rub on ird torsion bars if you have them) and sidepods. I wouldnt go that big on the front though, will reduce your turning circle somewhat...

31s will fit on the back no dramas, even with the longer IRS torsions bars. You might have to watch the offset of the rear wheels to avoid rubbing on the body. However, let me give you a tip. Don't run equal size tyres front and back or it won't go round corners very well at all. Afterall there is no weight in the front at all.
My tyre setup is as follows 31/10.5r15 (31inch tall, 10.5 wide) on the rear. 215/75r15 on the front. This just inside the legal limit for difference in tyre sizes. The rule is that is should differ by 15% maximum from memory. I still believe my front tyres are far too wide. The car would handle much better with something like a 185/65r15 on the front. And if I am battling understeer with my LWB buggy, you will be worse off with a SWB buggy as the weight distribution issues are worse in them.
Anyway, I spose what I am saying is this, find a skinny hard set of 31s for the back and something quite skinny but super soft for the front. Otherwise it will understeer like a pig, a trait buggies are notorious for even when well set up.
The other thing is tyre pressures. I am finally get the car to turn in properly and my tyre pressures are radical...would you believe 18psi in the front, and 38psi in the rear! I may even go up to 40psi yet.

Oh and another thing, keep your stock front swaybar on. It helps reduce plough understeer too.

I know you're gonna say, "but offroad handling won't matter". Well how are you gonna get to the sand and dirt? Unless you have the beach/trails on your doorstep, you will do about 50% of your driving on the road, so at least make it reasonable to drive there as well.

Pete, thankls for the info. Is yours body lifted? I've added a 3 inch body lift, I've got some 7 and 8 inch Eagle alloys coming for it with plenty of offset. We make wheel spacers and son on, so if nessesary I can make some for it ( obviously I'd prefer not to make it illegal)

I've got 5 inches of extra fender height in the body. 3 is heaps, I got carried away.

There are things you can do with brake setups to help extra width. For example, most wide 5 front disc brake kits add about an inch to either side. My advice is build it into the design so the engineer won't look at the offset, just the change in track.

And yes, spacers are really not a good idea.

Also, 8 and 7 inch wheels are gonna be huge for that car. put the skinniest rubber you can find on them or it will understeer very badly. See the real problem with buggies is that you need to employ almost the opposite of all the wheel/tyre ADRs to get them to drive properly. It's always gonna be a compromise for rego. That said, try and find something that is as good as you can get while still legal so you can insure the car properly and avoid risk of lawsuits and defects.



[ Edited on 27-6-06 by pete wood ]