Four-Wheel-Drive Tyres.

Please don't ask "what sort of four-wheel-drive tyre should I buy?" Get four people around a camp fire and you will get four different opinions on the best 4WD tyre!

What is important is that tyres be kept at their recommended pressures when driving on-road. It is often necessary to lower pressures for off-road conditions (mud, sand) but this can cause the tyre to "roll off" the rim under cornering loads. The danger is greatest with tube-less tyres because there is an instant loss of all tyre pressure which can lead to a roll-over even for an experienced driver. Pressures should be returned to normal as soon as possible, and definitely before resuming highway speeds. Useful gadgets: reliable tyre-pressure guage and an electric pump (or foot pump and strong legs).

BFG - BF Goodrich

The BFG All-Terrain and Mud-Terrain (left) tyres are popular in muddy old Victoria (some people think that BFG stands for Very Frightfully Good). The Mud-Terrain is rather more aggressive than the All-Terrain so it clears itself better although given sticky enough clay (left) its tread 4wd.sofcom.com --> can still get filled up. The All-Terrain is reported to wear well, particularly in the larger sizes, e.g. 235/80-ish.

Simex

Simex tyres tires --> are made in Malaysia, some of them from ex-Dunlop moulds. 4wd.sofcom.com --> The tyres are gaining a reputation for good value for money. This type (left) was fitted to the winning vehicle of the 1999 Malaysian Rainforest Challenge, in attendance at the Victorian Four Wheel Drive Show -
4wd.sofcom.com/4WD.html

Swampers

The escalating tyre war has given rise 4wd.sofcom.com --> to diameter creep, from the basic 31" (7.50x16) to 33", 35" and these 38" Super Swampers [7/'00].

The objectives are to climb steps more easily and to keep your diff' above the crown of the ruts dug by 4wd.sofcom.com --> the other guy.

Size Conversion

"Old" tyre dimensions are in inches, e.g. 7.50 x 16. The tyre carcass width and height are both 7.5", so there is no need to specifiy an aspect ratio (it is 1.0), and the overall tyre diameter is 2 x 7.5 + 16 = 31", in this case. The most common Jeep / Land Rover / Cruiser tyres were from 6.00 x 16 to 7.50 x 16, although some went up to 9.00 x 16. (A 7.50R16 tyre is just the radial-construction equivalent of a 7.50 x 16.)

Newer tyre dimensions are a mixture of metric and imperial quantities, e.g. 245/80 x 16, indicates a tyre carcass width of 245mm, an aspect ratio of 0.8 or 80% and a wheel rim diameter of 16"! A change became necessary when tyre technology enabled aspect ratios of less than 1.0. Low aspect ratio tyres give better on-road handling, all other things being equal, but there is still a place for the trusty 7.50 x 16 on 4WDs.