What is the advantage of a locking differential?

Question

I was looking into going on some light off-road trips in my new car, and while browing related info, I ran into this a lot: that all serious off-road vehicles require a locking differential.

My understanding of the locking differential is that the differential can be locked, meaning the left and right wheel are required to spin at the same rate. That is useful for situations where one wheel might not have traction, which would normally (without locking differential) cause it to spin and get the most torque. Locking differential prevents this by forcing both wheels to spin at the same rate, preventing the no-traction wheel from getting all the available torque. This much, I think I understand.

What I don’t understand is, how is that better than a traditional AWD system, where the car can decide which wheel gets the torque? In my mind, this is even better because as soon as the car detects loss of traction, it will cut the torque, achieving basically what the locking differential does without the downsides (like worse corner handling). For example, my new car, a Subaru Outback, supposedly comes with this kind of AWD system that can distribute torque as needed.

So my question is, why is a locking differential better than just having a normal AWD?

In: Technology

Answer 1

I think the key there is serious off road vehicles. In a pretty extreme off-roading situation, it’s likely that you will have no traction on one wheel, and then very quickly change to having no traction on the other wheel. In some offroad situations, you need to maintain momentum, and a computer controlled AWD system may react too slow to keep momentum, simply because it’s not designed for playing in the mud, or rock crawling. A computer controlled all wheel drive system is generally designed to help you maintain control of the vehicle and prevent slipping and sliding which could lead to an accident. Off-roading, especially with a locked differential, requires you having knowledge of how the vehicle will handle, and anticipating a certain amount of slipping and sliding.