BOILED EGGS... AND 4X4S

Boiled eggs – some like ’em hard, some like ’em soft, and some like ’em just in between. Interestingly, 4x4s are no different; and if you’re in the market for an off-road vehicle you may be wondering what classifies one 4x4 as “tougher” than another. Let’s take a look…

SOFT BOILED 4X4s

Firm on the outside, squishy on the inside: soft-boiled 4x4s are, ironically, also called softroaders. But what is a softroader? In most cases, softroaders are high-riding vehicles that feature 4WD, but lack a low-range (or reduction) gearbox.

Low-range allows you to reduce engine speed, while simultaneously increasing torque and vehicle control. This is particularly important when driving over rocks, where the term “slow and steady” is vitally important. Without low-range, you either run the risk of driving too fast over an obstacle, or you’re forced to ride the clutch in order to reduce engine speed. And the faster you drive, the greater the risk of vehicle and/or tyre damage.

Technically speaking, softroaders can tackle a lot more (in terms of off-road obstacles) than people give them credit for; but again, that comes at the risk of vehicle damage, reduced clutch life, and (more importantly) a definite decrease in vehicle control.

However, thanks to their supple suspension and 4WD traction, softroaders are usually great gravel-travellers. In other words, they’re primarily designed for gravel roads, minimal levels of snow and mud, and towing lightweight trailers.

In most cases, a softroader will feature independent suspension on all four wheels; this allows for maximum comfort off-road, but limits how much suspension travel (or flex) the vehicle has, and thus its ability to “find” traction through rugged terrain.

COOPER’S RECOMMENDED TYRE

Don’t waste your money on a set of dedicated 4x4 tyres. Sure, an aggressive tread pattern will look hardcore on a softroader, but what you really need is an all-terrain that offers great all-round traction and gravel-travel puncture resistance. Something like the Cooper Discoverer AT3 or Zeon LTZ.

Examples of typical soft-boiled 4x4s are:

• Toyota RAV4

• Jeep Renegade

• Nissan X-Trail

MEDIUM BOILED 4X4s

As expected, this is the market’s most popular segment. Medium-boiled 4x4s are often a technical balance between two forms of engineering, and the best place to confirm this is under the carriage.  

The suspension is the first give-away. In most cases, a medium-boiled 4x4 will sport independent suspension up front, and a solid axle at the rear. This offers the best of both worlds: a relatively soft (and responsive) ride on tar and gravel up front, and the benefit of increased ground clearance, added suspension travel, and greater load-ability at the rear.

There are exceptions to this: some vehicle manufacturers are adopting adjustable air suspension. The Land Rover Discovery is a prime example, as it uses air-adjusted suspension bladders that adapt to different terrain types and ground-clearance needs. But, on the whole, most medium-boiled 4x4s will boast independent suspension up front, and a solid axle at the rear. As a rule, however, they all feature low-range gearing, and more often than not, a ladder-frame chassis. A rear diff-lock is a bonus feature, but not a requirement.

COOPER’S RECOMMENDED TYRE

It will largely depend on your application, but if you’re an occasional off-roader, you’ll be happiest with a LT spec all-terrain, such as the Cooper Discoverer AT3 LT. If, however, you regularly load your vehicle and explore remote regions, then you’ll be better off with a set of S/T Maxx tyres, and perhaps even the STT PROs.

Examples of typical medium-boiled 4x4s are:

• Toyota Fortuner / Hilux
• Ford Ranger / Everest
• VW Amarok

HARD BOILED 4X4s

Bump them, bang them and abuse them, but there’s no need to worry because they’ll just bounce back for more – which is rather apt, as that’s exactly how they ride. If you’re sensitive to stiff suspension and a relatively hard ride, it would be best NOT to buy a hard-boiled 4x4.

But, what is a hard-boiled 4x4? Again, the best way to find out is a quick glimpse at the suspension. Here, there are no exceptions: hard-boiled 4x4s can be distinguished by their use of a solid axle at both front and rear of the vehicle.

This greatly improves a vehicle’s off-road abilities on rugged terrain. Having a solid front axle (SFA) not only reduces the chance of nose-diving into an obstacle, but also improves the vehicle’s ability to “find” traction (suspension travel) and maintain ground clearance. To put that another way: when one wheel drives over an obstacle, the entire chassis rises with the tyre’s ascent, thereby “creating” clearance under the chassis. To a large degree the inverse is true for independent front suspension, where the wheel (and suspension) move independently from the chassis, thereby reducing clearance to a certain extent.

Similarly, solid axle suspension is better suited to holes (or dips) in the road, where the suspension does all of the work (flexing) and the chassis remains mostly level. Independent suspension has a tendency to “max out” a lot sooner in terms of travel (flex), thereby causing the vehicle to pivot in and out of obstacles.

Lastly, solid axle suspension not only helps to keep a vehicle’s centre of gravity low when driving off-road, but also improves payload capacity, and reduces the chance of suspension damage when driving on rugged terrain.

But again, all of these (off-road) benefits come at the cost of refinement, and a noticeable lack of on-road dynamics and performance.

COOPER’S RECOMMENDED TYRE

Dedicated 4x4s generally spend a large portion of their time heavily packed or loaded (trailer / caravan); for this reason you need a tyre with great puncture resistance and a high payload capacity. If that’s the case with you and your 4x4, then restrict your tyre search to the S/T Maxx and STT PRO.

Examples of typical hard-boiled 4x4s are:

• Toyota Land Cruiser 70 Series
• Nissan Patrol
• Land Rover Defender
• Jeep Wrangler