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Tuning reference /springs

Springs (Rate)

Front vs rear spring rate sets the corner-balance floor. Softer end is the one that loses grip.

Your dataCar #3650· last 3 laps
Front travel avg63.7%
Front travel p9583.4%
Rear travel avg57.8%
Rear travel p9581.6%
Frames > 95% compressed0.49%

What it does

Springs support the car against weight transfer. The stiffer end of the car has less mechanical grip because the contact patch is loaded harder and unloaded faster. Counter-intuitive but consistent: the soft end keeps grip, the stiff end gives it up.

Forza shows spring rate in lb/in (or kg/mm). The numbers are car-specific — what matters is the front-to-rear ratio relative to weight distribution. A nose-heavy car can take stiffer rears than its weight split suggests, because the front already has plenty of static load.

Going too soft on both ends gives a wallowy car that bottoms out; going too stiff gives a skittish car that skips over bumps and lights up its tires.

In-game controls

Front springs
Range: Lower 1/3 of slider for road, mid for track, upper for stiff race cars
Raise →
less front grip (more understeer), faster response, more bottoming resistance
← Lower
more front grip (less understeer), slower response, risk of front bottoming
Rear springs
Range: Usually within 10–20% of front rate; closer to equal for RWD, stiffer-rear for FWD
Raise →
less rear grip (more oversteer), better rear bottoming resistance
← Lower
more rear grip (less oversteer), more squat under power

Watch these telemetry signals

  • Suspension travelsuspension
    Where: Corner panels, suspension bar (0..1, flashes red at >0.95)
    Hits >0.95 on bumps or compressions → too soft; barely moves over rough surfaces → too stiff
  • Tire slip angle (lateral)slipAngle
    Where: Corner panels, "slip A" — compare front vs rear
    Front >> rear in steady mid-corner = understeer (soften front or stiffen rear). Rear >> front = oversteer (the reverse).
  • Tire temperaturetireTempC
    Where: Corner panels, tire temp heatmap (cold blue → optimal green → hot red)
    Cold tires on one axle vs the other = that axle isn't loading its contact patch — likely too stiff for the surface

Symptom → fix

What you feel Likely cause Try this
Bottoms out over kerbs / crestsSpring rate too low for the suspension travel availableStiffen the axle that bottoms; if both, raise overall rate or raise ride height
Car feels wallowy and slow to respondBoth springs too softRaise both rates ~10% and re-test; pair with damper bump bump-up
Mid-corner push (steady understeer)Front too stiff relative to rearSoften fronts a touch OR stiffen rears (latter helps if front bottoms)
Mid-corner loose (steady oversteer)Rear too stiff relative to frontSoften rears a touch; check rear ARB first (cheaper change)

Symptoms that point here

Related

Anti-Roll Bars (ARBs)Dampers (Bump & Rebound)Ride Height