Trading Post

Many tradies like to dress up their work utes or vans and one of the favourite changes is to fit a set of flash wheels in place of the drab originals. However, it's important from a safety and liability point of view that you do your homework.

After-market wheel selection

The wrong place to start is where most of us kick off the wheel selection process: staring through the window of the local wheel shop or cruising wheel images on websites. This is less than desirable, because it's very easy to fall in love with a wheel shape, finish and pattern that you're sure will set off your pride and joy, only to discover that it won't be legal. The starting point with any after-market wheel selection is with the load rating of the wheel. Most flash wheels have passenger car load ratings that are often way short of the permitted axle loadings of light commercial vehicles.

Load ratings of replacement wheels aren't specifically mentioned in the current edition of Vehicle Standards Bulletin 14, with which State and Territory regulations largely comply, but VSB14 does say that original ADR compliance must be maintained. Also, permitted tyre dimensions and their load and speed ratings are very carefully spelt out.

It'd be a brave ute or van owner who put weaker than standard wheels and tyres on his or her machine.

Load and speed ratings

In general, your replacement wheel and tyre package must preserve the load and speed rating of the factory originals. However, because many after-market tyres are built for countries where speed limits are much higher than in Australia, there are some speed-rating concessions. Note, however, that the load rating is non-negotiable, according to VSB14: 'The load rating of the (replacement) tyres is not less than the lowest load rating listed on the tyre placard of the vehicle or equivalent variant of that model vehicle'.

A lower tyre speed rating is approved as follows: 'The speed rating of the tyres fitted to vehicles with special features for off-road use of at least 140 km/h ('N') when the tyre placard requires a higher speed rating than N, and for all other vehicles a speed rating of at least 120 km/h'.

Legal wheel size

Having reduced your search to wheels and tyres that comply in terms of speed and load ratings, the next step is to make sure the package is dimensionally legal.

VSB14 states that replacement tyres on light commercials and 4x4 utes (and 4x2 utes that are almost identical to their 4x4 cousins in chassis layout and wheel equipment) must not have a diameter more than 50mm greater or 26mm smaller than that of the standard tyres. On the question of tyre width, VSB14 allows a 50 per cent increase in tyre width over the fattest standard tyre option, but this is not allowed in some State jurisdictions - check with your local authority first. Within that tyre width allowance is a track restriction of 50mm over the maximum standard track width for that vehicle.

Some ute owners like the dual rear tyre look and the only way to achieve that legally is by fitting a dual-tyre and axle assembly from another vehicle. If the standard axle is retained the combined width of the dual tyres can't exceed the width of the original single tyre. The good news is that there is an increasing availability of ute and van compatible aluminium wheels, with load ratings around 1400kg, in the after market. There are also matching LT tyres in 17 inch and 18 inch sizes.

What about modifying suspension?

The jury is still out on the future legality of raised and lowered suspensions. We doubt that many tradies would want to lower their vehicles, but raised suspensions are quite popular, especially in the case of 4x4 utes.

It seems that the safest route is for a combined lift - suspension plus tyres - of 50mm. The Australian Automotive Aftermarket Association is lobbying the Federal Government for a nationally approved 75mm combined lift, but that hasn't been granted yet. It's vital that any aftermarket suspension modifications don't compromise your load carrying capacity.