(Updated on May 10, 2022)
All automobiles on the road contain devices between the wheels called differentials, or gear trains. The purpose of differentials is to allow the wheels of the vehicle to rotate at varying speeds. This is done by splitting the torque of the engine into two separate outputs.
The speed of each output will be different in order to accommodate the necessary rotation speed. Basically, when you go to make a turn, the inner drive wheel is going to rotate slower than the outer drive wheel of the gear train. If there were no differentials in your vehicle, then your turns would feel like they would in karts.
Not all differentials are designed the same way. In fact, there are different types of differentials that are made for vehicles. Each one has their own special quality and attributes. The best differentials for your vehicle will depend on whether you have 4-wheel drive, 2-wheel drive, front-wheel drive, and so on.
The two main differentials are limited slip differentials and locking differentials. These differentials have their similarities and differences. The similarities are that they both provide the same basic function for the wheels. This function is to provide more stable traction for the wheels and tires of the vehicle. The differentials are installed onto your vehicle’s axles in order to make this happen.
Most cars might come with an open differential, but those can cause the wheels to rotate in different directions and cause all kinds of problems. You will want either a locking differential or limited slip differential for better traction. We will go over the differences between the two now.
Related: Types of Drivetrains (Comparison)
Limited Slip Differential
Limited slip differentials provide your vehicle with the best traction around. Locking differentials might give you good traction too, but the traction that you will experience with limited slip differentials is better.
For starters, they will make it easier to turn on roads which are slippery and wet. If you live in areas which constantly have rain and snow, then you might want to consider having limited slip differentials in your vehicle.
Plus, the treads of your tires will stay in good condition as you accelerate regularly. There will be complete silence from the limited slip differentials too. Compare that to the tires on locking differential vehicles which get worn out treads quickly.
Of course, limited slip differentials don’t lock the wheels simultaneously at the same time on the axle. Some versions of the limited slip differentials have been found to be physically weaker too.
This means that you’ll likely have to replace them sooner than you would with the locking differentials. If you have a front axle application, some limited slip differentials may pull from one side to the next.
See Also: Differential Repair Cost
Locking Differential
People prefer locking differentials because they don’t require a lot of servicing or maintenance. They are also very durable and provide great traction on the road for the driver.
The key feature of a locking differential is how the wheels on the same axle will lock together. That way, when you go to turn the vehicle, both wheels will be forced to turn simultaneously no matter how much traction each wheel has.
All the applications are bolted into the system. There is no need to modify the axle shaft, axle, pinion, or ring.
Read Also: Average Cost of Differential Fluid Change
On the downside, the treads of your tires are going to get worn out fast. This will eventually cause steering problems to occur as they continue to get worse.
If you live in an icy or snowy environment, steering will be even harder with poor steering ability like this. You may even hear big banging sounds coming from the automatic lockers. These are sounds which will certainly make you want to reconsider whether you have the right differentials in your vehicle.
Who engages lockers on a paved road?
You wouldn’t want to do engage a locker on a paved road, unless that paved road had a lot of ice or snow and you needed to get yourself unstuck.
Would lockers let you retain control if a tire went off the road into deep mud in a serious rain? Or would limited slip be a better fit? Assuming we’re talking RWDs, which axle would you want sporting that?
I lost a FWD Toyota sedan a couple years back when it understeered on a mild turn, my front passenger tire drifted into the mud, and both steering and control were gone.
It pulled a couple spins until
the driver’s side slammed into a farm fence (and my head was smashed through my side window). Concussion took 6 months to heal from. And those were pretty standard road conditions for half the year around here, so I’m looking for a truck (that I can afford to write off if it’s trashed, so probably a mid-2000s Chevy Silverado) with which I could’ve kept power and steering in that same situation.
The biggest factor in how much control over the vehicle you have is your tire choice, not the differentials. If you were understeering, your front tires gave up grip for some reason.
Fancy differentials may help reduce understeer or oversteer on power, but they often don’t help off throttle and under braking. Fancy differentials are not an adequate substitute for running the correct tire for the conditions, no matter which wheels receive torque from the engine.
A rear wheel drive vehicle only has one differential, and it sits between the rear axles.
Buy the highest quality tires you can afford for the conditions you plan to drive in. Make sure you don’t drive too fast for the conditions, and it wouldn’t hurt to take a high performance driver’s education (HPDE) course for more experience driving at the limit under controlled conditions on a closed course.