RC drift car won't turn in? How to fix understeer
If the car pushes wide instead of turning in, the front doesn't have enough grip or the steering isn't doing what you ask. Fix tyres and camber first, then caster, then check the servo and steering for binding.
Why it happens
Turn-in needs front grip and quick, free steering. A hard front tyre, too little negative camber, a weak servo or a linkage that binds all show up as the same thing: the car goes straight on.
Check in this order
- Front tyres. Run a softer or grippier front compound than the rear.
- Front camber. Add negative camber, 1° to 2°, so the outside tyre stays flat in the slide.
- Caster. More caster helps the front dig in on turn-in; try the next caster block or shim.
- Steering. With the car on a stand, turn full lock both ways: it should move freely with no catch. Check the servo saver isn't too soft and the endpoints aren't limited in the transmitter.
- Rear grip. If the rear is very planted, the car can't rotate. A harder rear tyre lets the car turn.
Parts that fix it
- Front compounds: Drift Tyres
- Camber and caster adjustment: Turnbuckles, Steering block
- Faster, stronger servo: Servo
FAQ
How much front camber should an RC drift car run? Most RWD drift cars run 1° to 3° negative camber at the front. Start at 1.5° and adjust from there.
Can a weak servo cause understeer? Yes. If the servo can't move the wheels quickly under load, the car won't turn in and the gyro can't correct properly.
Why does my drift car turn in one way but not the other? Check steering trim, equal toe on both sides and that nothing is bent. An uneven servo saver or a bent arm shows up exactly like this.