How to pick the correct off-road tyres for your rig.
FITTING THE CORRECT TYRES TO YOUR 4X4 IS ONE OF THE MOST IMPORTANT TOURING DECISIONS YOU’LL MAKE.
TYRE performance takes on a whole new meaning when it’s applied to off-road four-wheel drives. Grip on wet and dry roads is important, but it’s stuff like puncture resistance, off-road grip (in sand and mud and everything in between) and load ratings that can make or break a 4WD tyre.
However, it can be a tough call when it comes time to replace your 4WD’S standard rubber with something a bit more flash. For starters, how four-wheel drive tyres are classified is confusing. There could be simple, general ways of defining tyre types, such as on-road, off-road and heavy-duty off-road, but it’s not that simple.
Many tyre manufacturers provide some kind of indication of a tyre’s abilities (for example, with star ratings or percentage of use on- and off-road), but because there is no standardised rating system, brands can’t be compared or relied on.
So, 4WD tyres are broadly grouped in three categories: Highway Terrain, All Terrain and Mud Terrain. Then there is the matter of Mud and Snow tyres, as well as Passenger construction and Light Truck construction tyres.
Highway Terrain (H/T) tyres are the lightest in construction and the quietest and the smoothest to drive on. These tyres, with a tread pattern much like a car tyre, are also usually the best for tarmac traction. H/T tyres are fitted to most new 4x4 wagons and some 4x4 utes as standard because they are often cheaper to produce than other tyres. As most new 4WD owners don’t go off-road, H/T tyres score well in the around-the-block test-drive for their smoothness. So, it’s a no-brainer that H/T tyres are the pick of almost all 4WD manufacturers.
Not only do H/T tyres have the lightest construction and most car-like tread pattern, they have a higher speed rating and lower load rating. They are ‘Passenger-rated’ tyres for this reason. If you have a 4x4 that’s used mainly on paved roads (with the occasional foray onto forest tracks) then it makes sense to use an H/T tyre.
Many OE tyres don’t have great grip, so when it’s time to replace them you usually have a wide choice of better tyres
A/TS are best for when you mix urban driving with the occasional off-road trip
to choose from. It’s also easier to find a direct replacement tyre when your vehicle has an odd tyre size or – in rare cases – is a large diameter tyre in, say, the 19- to 22-inch range.
All Terrain (A/T) tyres are the next step up from H/TS for off-roading. A/T tyres are usually built stronger and have better tread patterns for hitting the tracks, and they are the best compromise for when you mix urban driving with the occasional off-road trip. Depending on the specific tyre, it may be noisier and offer less on-road grip than an H/T tyre.
A/T tyres take in the middle ground, with typically a lower speed rating than an H/T – often around a T to H rating (see Speed Need, opposite page) – but have a higher load rating. However, not all A/T tyres are built equally tough, because tyre manufacturers design them according to what they believe is important. Some will have a tread pattern and carcass construction close to that of an H/T tyre, while others will have a stronger carcass and chunky tread similar to a Mud Terrain (M/T) tyre.
The way to tell if an A/T tyre is worth buying for off-roading is to check the number of plies (layers in the sidewall and tread area) it has compared with an H/T tyre. The A/T should also have a more pronounced and open tread pattern.
This is where Light Truck (LT) construction comes in – A/T tyres better for off-roading will have the LT designation. LT tyres have a stronger carcass so that they can meet the load requirements of light trucks. Even utes with a one-tonne (or more) payload have them as standard, so the tyres will handle the carrying capacity without popping a tyre. If you look at any new ute, you’ll see that an LT tyre doesn’t necessarily have an off-road tread pattern.
LT tyres can vary in toughness. The best way to tell is to see how many sidewall plies the tyre has – usually four plies in the tread area and two in the sidewalls is a good start. Eight- or 10-ply ratings are best for resisting stone damage and sidewall staking.
A Light Truck All Terrain tyre is the best all-round tyre for a 4x4, as it will do plenty of kilometres as an off-road tourer. As a bonus, in a 4x4 A/T pattern, they tend to have deep tread, so they last longer and have far better mud-clearing properties and puncture resistance than an H/T tyre.
M/T tyres (the heaviest and strongest construction, with a blocky, deep tread pattern) have a low speed rating and a high load rating. Their tread pattern is designed for muddy off-road conditions and, while they offer good grip in other off-road situations such as rock shelves, they are not the best for sand driving. On the road, M/T tyres can be noisy and harsh, and they don’t provide the same level of handling or grip as A/T or H/T tyres. The M/T’S extra rolling resistance also causes increased fuel consumption. It’s no wonder the M/T is favoured for competition trucks.
For heavy-duty off-roading, LT M/T tyres are the ultimate choice, as their heavy construction provides good puncture resistance.
Mud and Snow tyres should have better traction in snow, but ‘M+S’ (or M/S) just indicates tread pattern. For tyres to be marked as Mud and Snow, they must have outer tread grooves that lead into the centre of the tread. The ‘M+S’ marking also indicates at least 25 per cent of the tread area is an open tread pattern.
With tyres, it’s a shame you can’t try before you buy, but that’s the same with most consumables. At least with this guide, you’ll be able to go in with eyes wide open.