Complete Guide to Limited Slip Differentials
Limited slip differentials (LSDs) are the go-to performance differentials for racers, overlanders, work truck owners and more. They provide power and control that win on the track and let you explore rugged places with no asphalt in sight. Understanding LSDs takes time, because over the years, many manufacturers have come up with their own limit slip designs. This guide will walk you through the origins, benefits, and types of limited slip differentials so you can shop with confidence.
Differential Origins: Moving From Open Differentials to LSDs
Limited slip differentials came about in the 1930s, but differentials themselves began back in the day — way back in the day when ancient people needed to pull carts instead of drive cars. The need for differentials was clear. Even then, wheels needed to spin at different speeds to keep wheeled vehicles moving, so the differential was born.
Open Differentials Vs. Limited Slip
In more modern times, open differentials were created to provide equal power to a set of wheels while allowing them to turn at different speeds. With an open differential, one wheel could spin faster than the other, and the wheels would spin in different directions. The problem is, open differentials still give the same amount of torque or power to both wheels, even if one wheel has less traction. That used to be OK in most circumstances. For a long time, open differentials satisfied the need for most standard, casual driving. But humans didn’t stick with standard driving. We needed more.
We needed the ability to get more movement during turns.
We needed more control in winter.
We needed the power to explore places beyond asphalt roads.
And hence the limited slip differential entered the market.
What do Limited Slip Differentials Do?
Limited slip differentials give wheels the ability to spin at different speeds, but limit the difference in the speeds of the wheels. If one wheel is slipping, the LSD will distribute more power to the wheel with more traction. This gives a vehicle more speed on turns and control when one wheel is on a lower traction surface.
Why Limited Slips Matter During Turns
When a vehicle makes a turn of any kind, the outside wheel spins faster than the inside wheel, because the inside wheel is making a tighter turn than the outside one (in other words, the inside wheel is traveling a shorter distance than the outside wheel). Without any differential, the vehicle would probably fishtail because the inside wheel would be locked to the outside wheel’s speed, causing it to skid and create massive tire wear.
A differential allows those wheels to make a turn by letting them spin at different speeds, but the limited slip differential takes things a step further by giving the wheel with greater traction more power.
This is especially beneficial if one tire is on a low traction surface while another is on a higher traction surface (like dry ground vs. mud). In that scenario, going without a limited slip differential can leave you stuck in the mud (literally).
Limited Slip Differential Benefits
We’ve covered a lot of these already, but limited slip differentials are beneficial for a number of reasons.
Limited Slip Differentials…
- Give more power to the wheel with more traction
- Reduce steering wheel shake
- Let your wheels move in the same direction
- Slow down the wear on your tires
- Gets you out of a tight spot fast
- Gives you confidence and peace-of-mind
Types of Limited Slip Differentials (LSDs)
Categorizing limited slip differentials is complex. Even limited slip differential types have types. One way of categorizing a differential type is by when it limits slip, or distributes power to prevent a significant difference in wheel speed between tires.
One-way, two-way, and 1.5 way LSDs
One-way: 1-way limited slip differentials are made to limit slip during either acceleration or deceleration. These are most popular with front-wheel drive vehicles (FWD) because vehicles with a 1-way LSD can turn when the throttle is released.
1.5 way and Two-way: Both 1.5 and Two-way differentials limit slip during acceleration and deceleration, but 2-way differentials lock fully when speeding up and slowing down while the 1.5 will lock fully in one direction and partially on the other. Drifters tend to prefer 2-ways while most racers choose a 1.5.
Clutch, Gear, and Cone Type Limited Slip Diffs
Another method of categorizing limited slip differentials is by how they lock and limit the slip. There are many types of limited slip differentials, but for simplicity’s sake we’ll focus on the popular clutch type, gear type, and our unique cone-type differentials.
Popular in muscle cars from the 60s and 70s, clutch LSDs use clutch discs or plates (called clutch packs) and springs to get the friction necessary to lock.
A viscous lsd uses viscous couplings and liquid to create friction if the drive shaft rotates faster or slower than the differential housing (again, if one tire is on a surface with less traction than another).
Cone type limited slip differentials are similar to clutch LSDs, using friction lined cones and springs to lock when needed. Most Auburn Gear differentials use a unique cone clutch design to shift torque to the wheel with the most traction.
Getting Your Limited Slip Differential
While limited slip differentials are highly superior to open differentials, most vehicles that come from the manufacturer still come with open differentials. Auburn Gear is an American manufacturer of aftermarket differentials to distributors across the U.S.
Learn about our performance differentials to explore different limited slip differentials designed for racing, off-roading, overlanding, work trucks and more.