Modern 4x4s are incredibly capable. Systems such as Land Rover’s Terrain Response have made off-road driving incredibly easy, asking the driver to do nothing more than turn a dial, and leaving everything else in the hands of the car’s on-board computers.
While we’re talking about Land Rover, let’s take a moment to reflect on the company’s Range Rover Sport, which we tested not too long ago. In terms of breadth of capability, the Sport is an engineering marvel.
The SUV is ridiculously fast and corners as if it’s on rails, but still somehow manages to be very capable off road. It has a total of 278mm of ground clearance, total wheel travel of 546mm and a wading depth of 850mm.
The fact that a vehicle can be so capable both on road and off is truly impressive. It is a testament to what modern engineering can accomplish.
But the Range Rover Sport has an Achilles heel. The 4×4 rides on massive 21-inch rims shod with skinny 275/45 R21 tyres. And venturing onto a serious off-road trail with those tyres is looking for trouble.
Of course, this isn’t a problem exclusive to the Range Rover Sport. The Sport is merely an excellent example thanks to its breadth of capability.
The fact of the matter is, fewer and fewer 4×4 buyers have any interest in taking their vehicles off the beaten path. Instead, they want their SUVs to handle like sportscars on tarmac. And, while getting a 2500kg vehicle to accelerate from 0 – 100 km/h in five seconds can be done by sticking a suitably burly engine under its bonnet, bringing it back to standstill is more problematic.
To slow down a big SUV travelling close to 200 km/h requires massive brakes, which, in turn, demand large rims that can accommodate those brakes. So, if you plan on doing some serious off-road driving, you can’t simply swop out your large rims and low-profile tyres for something more sensible, since the brake callipers will dictate how small you can actually go.
We have to give Land Rover South Africa credit for realising the importance of tyres when it comes to off-road driving. There isn’t much that can be done about the size of the brakes, tyres and rims coming out of the factory, but Land Rover SA did acknowledge the fact that South African want a full-size spare. In the rest of the world, the Sport comes with a collapsible third row of seating. In SA these seats were removed to allow for the fitment of a proper spare.
Unlike Land Rover SA, some local manufacturers are now providing only a space-saver spare, or, even more worryingly: no spare at all. Some “4x4s” now come with nothing more than a tyre-repair kit. How a car can be marketed as a lifestyle/adventure vehicle, and then equipped with no spare, is beyond me.
Until a new sort of tyre is designed that is indestructible, and equally capable on road and off, I think we have a serious problem. It doesn’t matter how capable your 4×4 is if its tyres aren’t designed to handle tough off-road terrain.
Airless tyres are coming. Bridgestone and Michelin, for example, have both showcased impressive airless tyres. But this technology is still some way off, so what do we do until then?
Well, if you’re in the market for a 4×4, and plan on doing some serious overlanding, spend as much time investigating the tyres as the rest of the vehicle. Find out what the smallest rim size is that the SUV can accommodate. Make sure that the vehicle can be fitted with common size tyres that are widely available. You don’t want to have to search for some weird tyre in the north of Namibia or Botswana.
Also, make sure that the vehicle has a full-size spare, and check to see that it can be fitted with a roof rack or rear swing arm where a second spare can be fitted. If you’re going on a long overland trip, you should definitely take at least two spare tyres along. Otherwise, a simple piece of rubber might end up spoiling your entire trip.