choosing the right tyre for your 4x4
go where others fear to tread
Bought a 4x4? Even If You Only Plan To Use It For Very Occasional Off Road Use, Tyre Choice Is Crucial. Steve Walker Guides You Through The Options
There are more glamorous and exciting components on your car than the tyres but very few that have a greater impact on its performance. Tyres form the all-important connection between a vehicle and the surface it's driving on, ultimately determining the levels of grip and stability, while also impacting on handling and braking.
It's vital to get tyre choice right in order to optimise a vehicle's performance but in order to do that, you have to understand the type of usage to which it will be put. Off-road vehicles must cope with a huge variety of terrains: some will lead a mud-splattered existence churning up rutted tracks and wading through swamps while others will never leave the asphalt. So it's important for owners to choose tyres that fit in with the way their 4x4 will be used - that's a given. The problem is that there are a whole lot of tyres on the market. So just where do you start?
Tyres designed specifically for 4x4s can be grouped into three main categories. The anti-4x4 lobby would claim that most of these vehicles spend most of their time in urban centres, clogging up the streets, spewing forth vast quantities of pollutants and running over peoples' pets. Most off-road vehicles should, according to this argument, be equipped with rubber from group one - the on-road tyres.
Those who would have the 4x4 banned, or at least taxed into oblivion, might be misguided in some of their views but they are right to suggest that only a small minority of 4x4s will ever need tyres of a purely off-road variety. The products in the second category are really only for serious off-road use because people who venture from the tarmac only on a light or infrequent basis can select their tyre from the third group, that of the off-road/on-road all-terrain tyre.
If you're one of the scurrilous lot who bought your 4x4 for its rugged looks and commanding driving position without ever giving a thougt to matters of mud, then shame on you. Fortunately, you're far from alone. Off-road vehicles make very capable urban runabouts and contrary to what you might have been told, most of them take up no more road space than an average family saloon car while emitting no more CO2 than many of the luxury saloons and sportscars that are largely accepted on our streets. With on-road specific tyres fitted, an urban off-roader can be more rewarding still. These tyres are designed for stability and comfort with greater stiffness in the sidewalls to improve steering precision and tread patterns designed to break up vibrations and decrease road noise. Traction is obviously still key, even on tarmac, and models like the Goodyear Wrangler HP all-weather tyre have a soft-compound centre section for optimum grip as well as wide longitudinal grooves for water dispersion.
The other end of the scale is the pure off-road tyre and you should be able to spot one of these a mile off. Note the deep, aggressive tread pattern and, more often than not, the bold white branding on the tyre walls. The deep grooves are designed to exert a vice-like grip on slippery surfaces and to shed mud that might clog up the tread more easily. With off-road tyres, you can also expect the tread to extend down onto the sidewalls for better purchase in deep mud and beneath the rubber, hi-tensile steel reinforcement will protect against punctures. On the downside, the deep grooves and soft grippy rubber compounds combine to produce higher levels of road noise and less precise handling on the road. Motorists regularly using off-road tyres for on-road work may also find that they experience accelerated tyre wear. Goodyear's Wrangler MT/R mud-terrain tyre is an offroader in this mould.
All-terrain tyres offer a compromise between the tarmac dynamics of a predominantly on-road tyre and the abundant grip provided by serious offroad rubber. If your day to day pootling regularly takes in unmade roads and farm tracks, you'll be thankful for the extra traction that these tyres will give you. Indeed, if your vehicle is capable enough, you'll probably find that this kind of tyre will suffice for some pretty extreme off-road work. On the Queen's highways, meanwhile, you can still expect decent levels of handling composure, low road noise and better longevity than you'd get with a proper mud-plugging tyre.
The features on an all-terrain tyre are a mishmash of those found on the previous two types of rubber. Goodyear's Wrangler AT/R for example, features a less extreme tread pattern than the MT/R with irregularly shaped blocks for reduced vibrations on-road. The tread is deeper and more aggressive than the company's all terrain Wrangler HP tyre however, and it extends on to the tyre's shoulders for grip in deep mud. An additional benefit associated with all-terrain tyres and some specially designed on-road tyres is their performance in cold, wet or icy on-road conditions. The extra traction they provide can pay dividends and it's worth remembering that in the winter months, some alpine countries require the fitment of winter tyres by law.
There's much more to tyre selection than most motorists would credit and if you're the proud owner of a 4x4 vehicle, you've a trickier decision to make than other motorists. Try serious off-road work with tyres that aren't up to it and all the money you spent on that low-range gearbox and the advanced traction control system will be wheelspun away. By the same token, using off-road rubber on tarmac increases road noise while seriously effecting your vehicle's ride and handling. With 4x4s in particular, choosing the correct tyres unlocks a vehicle's true potential. Get it right and there should be no stopping you but get it wrong and you won't know what you're missing.