P.G. (Tas) replied:

Eli, in general, 285/75 tyres will (a) raise your gearing (lower numericaly, which means at any given speed the revs will be lower than what they are now at that speed). (b) It will be slightly harder for your engine to turn them (because of the size increase, gearing etc, it will require more torque to turn them (with the power of the 100 series you probably won't even notice it). (c) you will gain roughly 21 mm more ground clearance. (d) With so many different tread patterns and rubber compounds available it is hard to be definitive about drive train wear. The more grip, the more chance to wind up the drive train. As for fuel consumption, there may be a change in theory (it should give you a fraction better because of lowering the revs at cruising speed) but I doubt you will notice much either way . I hope this helps. Cheers

porl replied:

Also, i am lead to believe, which is a direct consequence of the gearing change already alluded to above, the vehicle may exhibit a tendency to run downhill at a greater accelerated rate when you are relying on your gearing to slow you down than as with the standard tyres. This led to one bulletin board visitor at another site, who obviously goes down a lot of very steep hills, to take his tyres back for a refund and put on A/T's of the original size.

Though he did admit that the revs were noticably lower on the highway (and the speedo was out about 5km/hr at highway speeds) which would mean i would have thought that unless you intend to rely on downhill engine breaking to any significant extent, the pluses of better fuel economy on highway runs and extra diff clearance (which you don't get from a body lift) would mean higher tyres is probably in the balance a good thing.

porl replied:

As P.G. said correctly, totally depends on where you are going. As an all round which is better than a road tyre at anything off road but not as good as a specific terrain tyre in the specific terrain (eg mud tyre in mud or balloon tyre in soft sand or tractor monstor tyre in just about anything) go for in my opinion the tried and tested, if you can afford it, BFG A/T or the Cooper equivalent or the new whatchamacallit Bridgestone tyre with the donut technology that is supposedly more puncture proof than the BFG or the Cooper. Or as one 4WD magazine the best tyre is the one with the best driver, or as another one said, the best tyre is the one that is black, round, inflated, and you can afford, but given prosaics are not much help the above should. Also, a friend just got back from a desert trip and his mate in a Pajero shreded two Yokohama Superdiggers, maybe it was his driving or maybe he had wrong pressures or maybe don't buy those tyres for that trip, but my mate with his Bridgestones didn't even get a puncture.

John replied:

Eli :

get a set of split rims and put a set of Jap Dunlop 7.50 x 16ins. x 8 ply's on and enjoy a trouble free and punctureless trip in the Outback, stuff all those American gizzmos ( Coopers) too full of BULLDUST !! and keep to a narrow tyre which is all you need-- believe me I have been there and done that with them-- you wont get better
John