Forza Horizon tuning basics: drivetrain, gearing and setup

A car's drivetrain decides which wheels receive the engine's power, and it shapes the whole character of the car. You can keep the factory layout or swap to another, and each choice has a personality.

All-wheel drive (AWD) sends power to all four wheels. It launches hard, puts power down cleanly out of corners and feels the most stable and forgiving, which is why it is popular for rally, dirt and high-power builds — at the cost of a little weight and liveliness.

Rear-wheel drive (RWD) drives only the back wheels. It rotates eagerly and can be coaxed into slides, but that same eagerness makes it prone to oversteer — the back stepping out — if you are heavy with the throttle.

Front-wheel drive (FWD) pulls from the front. It tends toward understeer, where the nose washes wide and resists turning under power; it is the least common competitive choice but can be light and efficient.

A drivetrain swap is a real mechanical change, so it also affects the car's Performance Index (PI) and can push it into a higher class — worth remembering when you build to a class cap.

Tyres are the only part of the car touching the road, so tyre pressure is one of the most influential settings you can change — and it is a balancing act. Lower pressure generally increases the contact patch and gives more mechanical grip, but softer tyres flex more and build heat faster, and a tyre that runs too hot loses grip and consistency over a long race.

Higher pressure runs cooler and can feel sharper, but pushed too far it shrinks the contact patch and the car starts to slide. The aim is a pressure that settles into a healthy range once the tyres are warm, not simply the lowest number.

Gearing controls how the engine's power becomes wheel speed — a direct trade between punch and outright pace. Shorter gears (and a shorter final drive) keep the engine in its strong rev range for quicker acceleration, but the car runs out of revs sooner and tops out lower. Longer gears stretch each ratio for a higher top speed at the cost of a lazier launch.

So tight, technical routes favour short, punchy gearing where top speed rarely matters, while long straights and highway runs reward taller gearing. Tunes also space the individual gears to keep the engine pulling smoothly where it counts.

Alignment is the geometry of how the wheels sit relative to the road, and its three values each nudge grip and steering feel differently. Camber is how far the tops of the wheels lean in or out: a little negative camber (leaning inward) helps the tyre stay flat and gripping through a corner, but too much reduces straight-line grip because less of the tyre touches the road.

Toe is whether the wheels point slightly inward or outward seen from above, trading straight-line stability against sharpness of turn-in. Caster is the tilt of the steering axis; more caster generally improves stability and gives a planted, self-centring feel with little downside, which is why tunes often run it fairly high.

These settings govern how the car's body moves over bumps and through corners. Stiffer springs and firmer damping keep the body flat and responsive, which suits smooth tarmac and quick direction changes. Softer settings soak up bumps and keep the tyres planted on rough surfaces, at the cost of more body roll — which is why dirt and rally tunes run softer than a track build.

Anti-roll bars fight body roll in corners, and their front-to-rear balance is a handling tool in itself: stiffening the front tends to add understeer, stiffening the rear tends to add oversteer. Adjusting that balance is one of the cleaner ways to dial out a handling problem.

The differential decides how power and braking force are shared between the driven wheels, split into acceleration and deceleration sides. A higher acceleration setting locks the wheels together more under power, improving traction out of a corner but making the car push wide; a looser one lets it rotate more freely. The deceleration side does the same as you lift and brake.

Aero, on cars with adjustable wings, trades top speed for grip: more downforce means better high-speed cornering but more drag and a lower top speed. Braking covers balance and pressure — balance shifts bias front or rear (more front is stable but pushes the nose wide, more rear helps rotation but risks locking the back), while pressure sets how hard a full press bites.

The thread through every setting is that there is no free lunch: more grip here means more heat there, more acceleration means less top speed. Tuning is the craft of choosing which compromises suit your car and event — which is why a proven shared tune is such a good shortcut while you learn. It hands you a balanced starting point in one share code; drive it as-is, or use it as a baseline and nudge a value now that you know what it does.