Differentials Explained

The differential is the single biggest handling lever most people never touch. Get it right and the car turns in, puts the power down and stops fighting you.

In Forza Horizon 6 the differential controls how the driven wheels share torque. Two numbers matter: acceleration lock, which works on the throttle, and deceleration lock, which works on lift-off. For rear-wheel drive road racing, run a moderate acceleration lock of around 40 to 55 percent so the car rotates and drives cleanly off the corner rather than pushing wide, and a low deceleration lock of 10 to 20 percent so it turns in. Too much acceleration lock is the most common cause of corner-exit understeer.

By Alexander Royle. Ten years sim racing, published gaming journalist, top-50 FH6 Rivals player. Updated 2026-08-03

What the differential actually does

A locking differential decides how much the two driven wheels are tied together. Fully open, each wheel spins freely and the inside one lights up out of corners. Fully locked, they turn as one and the car pushes wide. The sliders let you set that lock separately for on-throttle and off-throttle.

Acceleration lock

Acceleration lock applies when you are on the power. It ties the driven wheels together: a little helps the torque land cleanly, but too much forces both wheels to turn at the same speed, which stops the car rotating and pushes the nose wide as you feed in throttle. That is corner-exit understeer, and an over-locked diff is the usual cause.

RWD road racing: keep it moderate, around 40 to 55 percent. Enough to put the power down, low enough that the car still rotates off the corner.
FWD: 45 to 60 percent. Too much and you get power understeer and torque steer.
Reading it: nose washing wide on exit means it is too high, an inside wheel spinning up under power means it is too low. Adjust a few percent at a time.

Deceleration lock, the one everyone sets wrong

Deceleration lock applies when you lift off the throttle. This is the setting that quietly ruins handling. A high decel lock steadies the rear as you brake, which sounds reassuring but actually stops the car rotating and gives you understeer on the way into a corner.

Road racing: keep it low, 10 to 20 percent, so the car turns in.
If it will not rotate on entry, lower decel further before touching anything else.
Loose surfaces: a little more decel (25 to 40 percent) helps stability on lift-off over bumps and descents.

All-wheel drive differentials

AWD has front, rear and centre settings. The meta keeps the front accel lock low so the front wheels can steer, runs a moderate rear lock so the rear still rotates on power, keeps rear decel low, and pushes the centre balance as far rearward as the car will take.

Front accel: low, around 20 to 25 percent. Front decel: 0.
Rear accel: moderate, 50 to 60 percent. A fully locked 100 percent rear is a common cause of corner-exit understeer. Rear decel: 15 to 25 percent.
Centre balance: 75 to 90 percent rear. The most aggressive tunes sit near 90 for a rear-drive feel with AWD traction.

Drift differentials

Drift wants both rears locked together so the car slides predictably. Run high acceleration lock, 75 percent upward, and full 100 percent on lower-power builds. Add strong deceleration lock so the car rotates freely on entry. With very high power, sit at the lower end of both to keep the car catchable.

Frequently asked questions

What does acceleration lock do in Forza Horizon 6?

It ties the driven wheels together on the throttle. A moderate amount puts the power down cleanly, but too much stops the car rotating and pushes the nose wide on exit. For RWD road racing, around 40 to 55 percent is the sweet spot.

How do I fix corner-exit understeer in Forza Horizon 6?

Lower the acceleration lock. A high or fully locked accel setting forces the driven wheels to turn at the same speed, which stops the car rotating under power and pushes the nose wide off the corner. Drop it a few percent at a time until the car drives cleanly off the corner, around 40 to 55 percent for RWD.

How do I fix corner-entry understeer with the differential?

Lower the deceleration lock. High decel lock steadies the rear on lift-off and stops the car rotating, which is the most common hidden cause of entry understeer. For road racing, keep decel at 10 to 20 percent.

What is the best RWD road racing differential in FH6?

A moderate acceleration lock of around 40 to 55 percent, enough to put the power down while still letting the car rotate off the corner, and a low deceleration lock of 10 to 20 percent so it turns in. Too much acceleration lock is the main cause of corner-exit understeer.

What centre balance should I run on an AWD car?

As far rearward as the car will take, usually 75 to 90 percent rear, with low front acceleration lock so the front can steer. This gives a rear-drive feel with AWD traction.

Put this into practice: the FH6 tuning calculator builds a full setup for any of 630 cars, and the meta cars list shows what to build first.