Truckster (Vic) replied:

What sort of weight is the unit all up?

Is that the reason for the dual wheels, for legality on weight?

Stonebreaker replied:

Especially when driving on loose sand, dual wheels are a hindrance. The wheels carve through sand, and so dual wheels tend to build up a mound between and before them, and as a result you continually have to climb this mound they throw up. Also, if there is not much room between the tires, ypu cannot lower pressure very much when driving on loose sand. I'ld recommend replacing them with broader rims and tires if you can. On my 5,5 tonne truck I've replaced dual 6" rims, 7.5" tires with single 9" rims, 10.5" tires, 12-ply rate, and have travelled thru Africa on these without trouble.

Member -Bob & Lex (Sydney) replied:

The duels are for the weight but you might be able to get singles for it. Go to a truck tyre place as they will know what your options are.

Luck1 replied:

Thanks to Members for your responses, helps a new chum a lot. I have noticed in Forum pages refrence to "Engineers Certificates" for vehicle modifications, can anyone recommend an Engineer in Perth WA for this work? Regards

Peter 2 replied:

A friend of mine has a Canter 4x4 and was faced with the same problem.
Here in NSW if he fitted singles to the rear it was illegal and could not even be engineered as the manufacturer did not make a version that had singles on the rear. He did actually drive it with a single wheel on the rear until the RTA inspectors defected it!

Eric Experience. replied:

Luck1.
The duals are not realy that bad in sand, the low gearing of the mazda can easily overcome any build up in front of the wheels. you can make things a lot better by changing your rims to the wider ones used on the 4 tonne model, because the tyres are wider [8.25] there is more offset on the rims so when you fitt the 7.5 you get more space between the tyres this makes it possible to run at much lower pressures which will make sand driving very easy, having towed out plenty of vehicles using a tow truck with duals I say stick with the duals and keep it standard and legal. The road trians that carry cattle out of outback stations use duals and tow up to 4 trailers over sand,
Eric.

Eric Experience. replied:

Luck1.
The rock throwing problem is the main reason the wider ofset wheels are better, if the tyres are far enough apart the rocks wont stay in there long enough to be a problem. The wheels on the mazda are a world standard wheel as used on a lot of trucks from about 1950 onwords, the Internationals and Dodges used by the PMG in about 1975 used them with 8.25 tyres, there is plenty of these wheels around because those trucks were rust buckets. Eric.

Brad and His Disco replied:

Hi,

Having single wheels setup on a truck this size, with a load as high as the camper would be extremley dangerous. I would compare it to having cheep retreads on the steer tyres. Avoid singles on these types of trucks at all costs.

Friend of mine had singles on a truck like this, rear tyre blew out on the free way, only way the truck was going was over on its roof.

Would strongly advise against this as a safety issue.