Anshuman Bishnoi, an experienced off-road enthusiast from the National Capital Region put four SUVs to the test on a sandy, rutted and slippery climb. A last-generation Toyota Fortuner 3.0 4X4 attempts the obstacle first, and really struggle to climb despite carrying momentum and trying a couple of times. The latest-generation Toyota Fortuner 2,8 4X4, a Ford Endeavour 2.2 4X4 and an Isuzu V-Cross 4X4 are the other vehicles that take on this obstacle. Watch how the Isuzu simply outperforms the other SUVs, all thanks to its differential lockers.
Differential locks: Why they really matter off the road!
A differential lock is a mechanical (in some cases electro-mechanical device) that splits torque evenly between two wheels of an axle. It can be fitted to both the front and rear axles of a four wheel drive car/SUV. To illustrate with an example, consider the Isuzu V-Cross with a 2.5 liter turbo diesel engine, which makes abut 134 Bhp-320 Nm. In four wheel drive mode with the low range engaged, this engine delivers about 800 Nm of peak torque thanks to the reduction ratio of 2.2:1.
So, when the Isuzu is equipped with differential locks on the front and rear axles, and when the differential locks are engaged, each wheel gets about 200 Nm of torque. And this brute torque is what allows the Isuzu V-Cross equipped with ARB Air Lockers (A brand of aftermarket differential lockers) that allows the pick up truck to make such a tough climb in sandy terrain look so easy. These differential locks (that can be electrically activated with the press of a button), costs about Rs. 2.5 lakhs for both the front and rear axles.
Though the Toyota Fortuner 2.8 4X4 has a very competent four wheel drive system and the A-Trac traction control system, it still has to be revved quite high and a lot of momentum needs to be carried in order to complete the obstacle. While momentum and the 4×4 system+A-Trac allows the Fortuner to power its way across the obstacle, it’s not exactly easy on the mechanicals. The suspension will take a beating when a vehicle is powered across an obstacle and many other components such as the steering and the transfer case will come under great stress during such moves.
The same is true of the Ford Endeavour 2.2, which also gets a four wheel drive system, a competent traction control system and even factory fitted differential locks on the rear axle (on the facelifted model). Just like the Fortuner, the Endeavour 2.2 needs to be powered across the uphill climb. Again, this is not easy on the SUV, and the chances of mechanical damage is quite high. This particular Endeavour is running aftermarket Old Man Emu suspension with a 1.5 inch lift, which means that it has more ground clearance than the stock model. The stock version would have gotten beached on this obstacle thanks to its relatively low fuel tank.