Limited-slip differentials
Limited-Slip Differentials
Limited-slip differentials (LSDs) are designed to improve traction by reducing excessive wheelspin while still allowing some speed difference between wheels on the same axle. They represent a compromise between open differentials and fully locking differentials, offering improved off-road performance with minimal impact on everyday drivability.
What Is a Limited-Slip Differential?
An LSD limits the amount of torque difference between wheels by using internal mechanisms such as clutches, gears, or viscous fluids. Unlike a locker, it does not fully lock the axle but biases torque toward the wheel with more traction.
Common Types of LSDs
Several LSD designs are commonly found in overland-capable vehicles:
- Clutch-type LSD – Uses friction plates to resist wheelspin
- Gear-driven (torsen) LSD – Uses helical gears to bias torque
- Viscous LSD – Uses fluid resistance to limit speed difference
Each design varies in responsiveness, durability, and maintenance requirements.
How LSDs Improve Traction
Limited-slip differentials improve traction by:
- Reducing single-wheel spin
- Transferring torque to the wheel with better grip
- Maintaining smoother power delivery than lockers
They are particularly effective in conditions where traction is uneven but not completely lost, such as gravel, wet dirt, snow, or shallow mud.
Off-Road Use Characteristics
LSDs function automatically and require no driver input. This makes them well-suited to:
- Mixed-surface driving
- Long-distance overland travel
- Vehicles that spend significant time on-road
However, LSDs may struggle in situations where one wheel has zero traction, such as lifted wheels or deep cross-axle obstacles.
Importance for Overlanders
For many overlanders, LSDs provide an excellent balance of capability and simplicity:
- Improved traction without driver intervention
- Minimal impact on steering and handling
- Lower drivetrain stress than lockers
- Reduced maintenance complexity
They are especially valuable for solo travelers who want predictable vehicle behavior.
Limitations
Despite their advantages, LSDs have limitations:
- Cannot provide full lock when traction is extremely uneven
- Clutch-based units wear over time
- Performance varies depending on design and condition
In highly technical terrain, LSDs are often supplemented by lockers or electronic traction control.
Conclusion
Limited-slip differentials are a versatile and effective traction aid for overlanders operating across varied terrain. While not as extreme as mechanical lockers, they significantly improve vehicle control and confidence in low-traction conditions, making them a practical and widely used solution for expedition travel.