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.

4 x 4 Australia - - Contents -

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.

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