CAR DRIVETRAIN
2WD vs 4WD, diff types, drivetrain components
2WD vs 4WD
2WD
Lighter, cheaper, simpler to maintain. More driver skill required — throttle steering technique. Better for technical courses where rear traction control is a skill. Preferred for racing buggy categories. Less grip on loose surfaces.
4WD / AWD
More traction, easier to drive at speed. Heavier due to front driveshafts and diff. Better for bashing, rough terrain, and high-power applications. Front diff tuning (oil viscosity) affects handling significantly.
DIFFERENTIAL TYPES
| TYPE | BEHAVIOUR | BEST FOR | NOTES |
|---|---|---|---|
| Open diff | Power to wheel with least resistance | On-road, smooth surfaces | Simple, cheap. Spins inside wheel when cornering. |
| Ball diff | Adjustable slip via spring tension | Racing — touring/buggy | Tunable preload. Goes tight or loose. Wears over time. |
| Gear diff | Mechanical limited slip | General use | More durable than ball diff. Fixed slip characteristics. |
| Oil-filled diff | Smooth progressive slip (oil viscosity) | Bashing, crawling | Silicone oil: thicker = more locked. Tune by weight (eg. 5000cst, 10000cst). |
| Spool (locked) | Both wheels always same speed | Drag racing, oval | Maximum traction straight line. Destroys tyres in corners. |
SLIPPER CLUTCH
SLIPPER CLUTCH
Spring-loaded clutch between motor pinion and main gear. Protects drivetrain from shock loads — landing jumps, rocks, sudden traction changes. Adjust tension (tighter = more power, looser = more protection). Set by tightening until it just stops slipping under hard throttle on carpet.
DRIVESHAFTS
DOG BONES
Simple cross-pin design. Cheap and light. Limited articulation angle. Pops out under extreme flex or high power. Common on budget and mid-range cars.
CVDs (Constant Velocity Driveshafts)
Smooth power delivery at any angle. Won't pop out. More expensive. Required for high-power builds and vehicles with large suspension travel. Standard upgrade for crawlers.