Ask the Editors: Differential Differences
It’s all about traction.
Absolutely – let’s start with the basics. At its very simplest reduction, a differential is simply a gear arrangement that distributes power from the driveshaft to the wheels. If you think back to the “pumpkin” found on the underside of nearly any pickup truck imaginable – you have the driveshaft entering the front – then axles jutting out from either side of the box toward the wheels. Inside you have gears turning the spinning rotation of that singular driveshaft into the forward (or reverse) rotation of the axle(s) and thus the wheels themselves.
Simple enough concept but it comes with one major weakness: If one wheel coming from the differential is slipping (say on a patch of ice) and the other isn’t, the even rotation of the driveshaft means you are going to do little more than spin yourself in circles. Enter the locking differential. What this does is replicates the experience of wheels that aren’t driven individually; but rather connected across one single axle. In short, both wheels are going to turn in perfect unison no matter the traction situation.
Everyone’s happy then? Not so fast. The downside to locked differentials is that they are clunky and rapidly accelerate wear of things like tires because now you are applying even rotational force even if traction is available under a given wheel. So a compromise was devised – the limited slip differential.
Limited slip differentials operate more smoothly and the main benefit is that they shift a portion of the torque coming in off the shaft to the wheel with the most traction while limiting the slip on the wheel with the least. The downside is that they are not capable of 100% lockup even if you decided that’s what you needed for your situation.
Can-Am’s Visco-4Lok is a mix and match/ best of both worlds approach. It’s a limited slip situation all the time but when LOCK is activated, you guessed it, it switches to a locked front differential on the fly.
