Lockers, or locking differentials, are essential components in off-road and 4×4 vehicles that significantly improve traction by ensuring both wheels on an axle rotate at the same speed. Unlike an open differential, which allows wheels to spin at different speeds, a locker forces equal power distribution, preventing one wheel from spinning freely while the other remains stationary.
Types of Lockers
There are several types of lockers, each with unique characteristics:
1. Automatic Lockers
- Engage without driver input and lock the differential when needed.
- Examples: Detroit Locker, Aussie Locker.
- Best for off-road use, but can be unpredictable on pavement.
2. Selectable Lockers
- Allow the driver to manually engage or disengage the locker.
- Operate via air (ARB Air Locker), electric (E-locker), or cable mechanisms.
- Ideal for off-road driving, providing control over traction.
3. Limited-Slip Differentials (LSD)
- Not true lockers but help distribute power when one wheel loses traction.
- Examples: Torsen, clutch-based LSDs.
- Suitable for mixed terrain where full locking isn’t necessary.
4. Spool Lockers
- Permanently lock both wheels together.
- Used in extreme off-road racing but impractical for daily driving.
When to Use Lockers
Lockers are beneficial in challenging terrains where traction is uneven:
- Rock crawling: Prevents wheel spin when navigating obstacles.
- Deep mud or snow: Ensures both wheels push forward.
- Steep inclines: Provides equal power to climb efficiently.
- Rutted trails: Helps maintain momentum when one wheel is airborne.
However, lockers should not be used on dry pavement, as they can make turning difficult and cause excessive tire wear.