Traction: The double-edged sword in off-road driving


D4---Offroad20151006If you have been following my articles about four-wheel driver driving, I have mentioned before that the two most important factors in off-roading is ground clearance and traction. I think I have covered traction several times from the hardware side. So this time, let’s tackle the subject of traction and, yes, contrary to what many believe in, there is also such a thing as “too much traction.”

Despite all the traction aids that can be found on various 4WD vehicles available in the market today, every budding mudslinger must understand that every new 4WD sold has the ability to create so much wheel turning action or torque even on 100-percent tractive surface. This is called wheelspin or for paved road pounders, a tire burnout. So can you imagine how easy it is too lose traction on less tractive driving surfaces?

As a 4WD off-road driving instructor, I have seen both new and seasoned off-road drivers make the biggest no no of them all, which is to mash the accelerator pedal once the vehicle starts slowing down on slippery terrain. To be honest, this sometimes work: operative word “sometimes.” But most of the time, it doesn’t and only aggravates an already bad situation that can turn to worst or become dangerous. Let’s analyze the driving inputs that happens when off-roading.

With a vehicle on first gear and 4WD-low, while moving forward on a muddy, slippery incline, gravity and the not so tractive surface will start to come into play. If the driver has not applied enough momentum to the vehicle, it can prevent the vehicle from making progress going forward. The normal thing to do is step on the accelerator, right? Wrong! What has happened is the vehicle slowed because the wheels lost traction and started to wheel-spin.  What caused this is the vehicle is at its lowest gear setting and the 4WD system is in low-range. Basically, this slows the vehicle down by at the very least half the speed, but torque or driving force was multiplied to make the wheel spin. This makes it very much easy for the tires to rip the already slippery surface and eventually just make the wheel spin. But that won’t make the vehicle move forward. When this happens, inexperienced drivers usually start pressing on the accelerator more and if the conditions are right, just make the tires dig deeper and eventually get the vehicle stranded.

Some will say that in that case, one should get a set of aggressive mud terrain tires for better traction. Not so all the time. In certain conditions, an aggressive mud tire can actually can sink your vehicle deeper and quicker.

The solution is to find the just right amount of forward motion to overcome the slope and just enough traction for the tires to get just enough bite to move the vehicle forward. Going back to the conditions I mentioned earlier on 4WD low range in first gear on a slippery slope  – the vehicle has too much torque, enough to rip thru the driving surface but not enough to make the vehicle move. Try starting in second gear and gradually accelerate before hitting the slope; starting on second gear will lessen the amount of torque applied to the wheels by the engine and the drivetrain will gain better traction to move the vehicle forward. This is called gear layering.

On flat boggy surfaces, you may even want to shift up to third gear once the vehicle starts to slow down again, because second gear may make the wheels tear thru the tractive surface again. Do remember that on third gear, even in low range, your vehicle may be moving fast enough that a sudden contact of the tires on a good patch of tractive surface will suddenly accelerate the vehicle and the driver may lose control of the vehicle. So caution is a must when doing gear layering.

Going back to the saying too much traction; there is such a thing in off-road driving and the consequences when this happens can be, at the least, unnerving and can result to, at the most, severe damage to a vehicle’s drivetrain. Damage to the drivetrain can happen when driving on rocky terrain and your drivetrain is not robust enough and you give the accelerator a healthy stomp. Unless you have a spare for each axle side of your vehicle and the mechanical skills to remove the broken axle and install the spare, you are stranded off the road.

I can keep rambling about traction and get technical about it and readers can just get bored and lose interest. But if you bother to analyze what I said and do some cautious application of what has been said here, you have made the first step in proper off-road driving.  In a nutshell, it is best to reflect on the creed of the Camel Trophy that is probably the most legendary off-road driving event of all time: “As slow as possible as fast as necessary.” Happy trail driving and thread lightly.


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