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LSD

Car culture term

What is LSD?

Limited-slip differential. A differential that distributes power between the left and right wheels to reduce wheel spin under acceleration.

LSD (limited-slip differential) is a differential designed to distribute power between left and right wheels more aggressively than an open differential. An open differential allows one wheel to spin freely if it loses traction, which kills acceleration. An LSD locks (or partially locks) the two wheels together when slip is detected, transferring more torque to the wheel with grip.

LSD types include clutch-pack (mechanical, common in performance cars and trucks), Torsen (mechanical, gear-based, smooth operation), helical (similar to Torsen, common in modern cars), viscous (silicone-fluid based, simpler but less aggressive), and electronic (computer-controlled clutch packs, increasingly common in modern AWD systems). Each has different characteristics suited to different applications.

Most performance cars come with an LSD as standard equipment. Honda Civic Type R, Subaru WRX STI, Nissan Z, and most BMW M cars all have LSDs. Aftermarket LSDs are common upgrades on cars without one (Mazda Miata, older RWD cars), and LSD upgrades for cars that already have factory LSDs are popular in racing applications.

Related terms

LockerTorsenRWD

Frequently asked questions

What is the difference between LSD and locker?
LSDs partially lock under load, allowing some differential action. Lockers fully lock both wheels together (either mechanically or electronically when engaged). LSDs are smoother for street use; lockers provide maximum traction for off-road or drag racing applications.
Do all sports cars have LSDs?
Most modern performance cars do, but not all. The Mazda Miata base trim has an open differential; the Sport and higher trims have a Torsen LSD. Many modern hot hatches have factory LSDs (Civic Type R, Megane RS). Some entry-level sport coupes use brake-based traction control instead of a mechanical LSD.
Is a Torsen LSD better than a clutch-pack?
Torsen offers smoother engagement and minimal maintenance (no clutch wear). Clutch-pack offers more aggressive lockup characteristics, often preferred for drift or drag applications. The choice depends on use case. Torsen is more common in factory applications; clutch-pack is more common in racing applications.
Can I add an LSD to a car without one?
Yes. Aftermarket LSD units (OS Giken, Cusco, Wavetrac, Quaife) are available for most popular performance platforms. Installation typically costs $1,500-$3,000 plus labor. The benefit is improved traction under acceleration and better cornering exit performance.
Do LSDs need maintenance?
Mechanical LSDs need fluid changes (specialty differential fluid, typically every 30,000-50,000 miles). Clutch-pack LSDs may need clutch replacement or rebuilding after extensive use (50,000-100,000 miles depending on use). Torsen and helical LSDs are nearly maintenance-free except for fluid changes.
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