There’s plenty of mods to make your 4WD more capable, but at the end of the day if you can’t get grip – you’re going nowhere fast, so tyre choice can be the single most important modification you can make to your 4WD!
So how do you choose a tyre? Firstly, make an honest assessment of your intentions with the vehicle. As with most 4WD modifications – to gain off-road ability, it’s generally going to sacrifice some on-road drivability, so knowing exactly what your priorities are and what you’re prepared to sacrifice will make the choice easier.
There’s a lot to know about tyre technology, but for this brief article we will look at three major factors for choosing a tyre – tyre size, tread types, load ratings.
Fitting oversized tyres increases the ground clearance of the vehicle making it more capable off-road but there are lots of things to take into consideration. Firstly, is the legality. This varies state to state but in NSW, any increase in tyre diameter must not exceed 7% of the manufacturer’s specified largest diameter option for that model vehicle, as listed on the vehicle’s tyre placard.
Tyre width must also remain in-line with the vehicle’s body work and be adequately protected by the mudflaps with an overall track width increase of no more than 50mm for 4WD vehicles. Generally, anything that’s road-legal won’t affect your insurance, but it always pays to check with your insurance company before doing any modifications.
Next, consider how the larger tyres affect handling and performance of the vehicle. The increased sidewall size of the tyre will lean over more while cornering, leading to less responsive steering. Keeping it within legal limits will reduce this, but you still should adapt your driving style to suit.
The larger diameter tyres will also reduce acceleration responsiveness and cause premature wear on components such as clutches due to requiring more effort from driveline components to turn the bigger tyres. Certain vehicles will also have limitations on tyre sizes, so it pays to speak to an expert on your particular vehicle.
The next factor is tread types. The three main types of tyres for 4WDs are Highway-Terrain (HT), All-Terrain (AT) and Mud-Terrains (MT). Most 4WDs come standard with an HT tyre or a very road-orientated AT tyre and are generally not considered suitable for anything more than dirt roads.
Generally speaking, the more aggressive the tread pattern on a tyre, the nosier it will be on-road, the faster it will wear on-road (tread compounds can also be a factor) and the higher the rolling resistance will be, which can lead to higher fuel consumption. However, the flip side is off-road grip.
Most good quality AT Tyres will work well on the beach, handle most off-road situations and still handle quite well on the road. However, if you are thinking of doing some really serious off-roading and lot’s of it, then an MT tyre might be better suited. There are also some hybrid style tyres on the market that offer features off both, so it’s worth speaking to an expert or doing plenty of research on the features of each tyre.
The load rating is another important factor. Most after-market tyres developed for the 4WD industry these days are light truck (LT) rated but it’s important to insure when fitting new tyres that they carry an “equal to” or “greater than” load rating than what’s specified on the vehicle’s tyre placard. This should ensure the tyres handle the weight of the vehicle and any additional weight, right through the maximum Gross Vehicle Mass (GVM).
Any tyre service or 4WD accessories shop should be able to give you all this information about the tyres they sell, so make sure you ask the questions. New boots for your 4WD should be high on your shopping list and will greatly improve your 4WDs capabilities, so you can spend less time getting recovered and more time enjoying the great outdoors.
THANKS TO TJM HUNTERVALLEY, OUR 4WD EXPERTS