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Circuit Tuning Guide

Technical Circuits — Tight Corners, Short Straights — Tune for Cornering Grip & Maximum Downforce

Tires
CompoundBest ForClassWidth FWidth RPSI FPSI RNotes
StreetROAD — CasualD – B205–225215–2353029Low grip, saves PI
SportROAD — CircuitC – A225–245235–2652928Good all-round road tire
Semi-SlickROAD — CircuitA – S1245–265255–2852827Track-focused, road legal
Slick RaceROAD — CircuitS1 – X265–295275–3152726Max tarmac grip, no offroad
RallyMIXED — Road + dirtAny245–265255–2852524Compromise on both surfaces
SnowSNOW — Winter eventsAny215–235225–2552726Required for snow/ice surfaces
Losing traction mid-corner → drop PSI 1–2 · Not enough grip → match compound to surface first
Tire Width
PowerRWD FrontRWD RearAWD FrontAWD Rear
Under 300 hp215–235245–265225–245235–255
300–500 hp225–245255–280235–255245–270
500–700 hp235–255270–295245–265260–285
700–1000 hp245–265285–315255–275275–300
1000+ hp260–280305–345265–285290–315
Losing corner grip → widen rear 5–10mm · FWD understeer → widen front 5–10mm vs RWD
Gearing
Under 160 mph4.20 – 4.50
160 – 180 mph3.80 – 4.20
180 – 210 mph3.40 – 3.80
210 – 240 mph3.00 – 3.40
240 mph+2.60 – 3.00
Hitting rev limiter before straight ends → lower Final Drive · Bogging out of corners → tighten gears 2–3
6-Speed
Under 180 mph
~200–500 hp
Mult.0.76
Final Drive4.00
1st3.10
2nd2.36
3rd1.79
4th1.37
5th1.04
6th0.79
7-Speed
180–200 mph
~400–700 hp
Mult.0.78
Final Drive3.60
1st3.20
2nd2.50
3rd1.95
4th1.52
5th1.19
6th0.93
7th0.72
8-Speed
200–220 mph
~600–900 hp
Mult.0.80
Final Drive3.50
1st3.20
2nd2.56
3rd2.05
4th1.64
5th1.31
6th1.05
7th0.84
8th0.67
9-Speed
220–240 mph
~800–1100 hp
Mult.0.82
Final Drive3.20
1st3.30
2nd2.71
3rd2.22
4th1.82
5th1.49
6th1.22
7th1.00
8th0.82
9th0.67
10-Speed
240+ mph
~1000+ hp
Mult.0.84
Final Drive2.80
1st3.40
2nd2.86
3rd2.40
4th2.02
5th1.70
6th1.43
7th1.20
8th1.01
9th0.85
10th0.71
Gearing Quick Adjustments
Alignment
Camber
Front-1.5° to -2.5°
Rear-1.0° to -1.5°
Understeer mid-corner → more negative front camber · Rear instability → reduce rear camber
Toe
Negative = in · Positive = out
Front0° to +0.2°
Rear-0.2° to -0.4°
Sluggish turn-in → add front toe-out · Snap oversteer → add rear toe-in
Caster
Angle5.5° to 7.0°
Car unstable on straights → raise caster · Slow steering return after corners → raise caster
Antiroll Bars — RWD
Stiffer front = less oversteer · Stiffer rear = less understeer · The gap matters more than the values
Front25 – 35
Rear15 – 25
GoalStiffer front reduces oversteer
Oversteer → stiffen front ARB or soften rear · Understeer → stiffen rear ARB or soften front
Antiroll Bars — AWD/FWD
Stiffer rear reduces AWD/FWD understeer · FWD: very soft rear allows rotation
AWD Front20 – 28
AWD Rear28 – 38
FWD Front15 – 25
FWD Rear25 – 38
AWD/FWD understeer → stiffen rear ARB · Traction loss over bumps → soften rear ARB slightly
Springs
lbs/in — Ride Height: minimum available
Rear = Front + 20–30 lbs/in · Pick front by weight, add ~25 for rear
Light (<2,600 lbs)F 250–425
R 275–450
Sport (2,600–3,400)F 400–600
R 425–625
Muscle (3,400–4,200)F 550–800
R 575–825
Heavy (4,200+ lbs)F 700–1000
R 725–1025
Traction loss over bumps → soften springs · Too much body roll → stiffen springs within weight range
Springs — Notes
Rear heavy carRear springs stiffer
Front heavy carFront springs stiffer
Stiff platformMin may exceed lower bound — use min
RuleMatch stiffness to axle weight class
Rebound
Controls extension speed · Stiffer front = resists dive · Stiffer rear = resists squat
Front7.0 – 9.0
Rear6.0 – 8.0
Car wallowy → raise rebound · Bouncing over bumps → rebound too low
Bump
Controls compression speed · Set bump first · Rebound = bump × 2
Front4.0 – 6.0
Rear3.5 – 5.5
Skipping over bumps → lower bump · Diving hard on entry → raise front bump
Aero
FrontMaximum available
RearMaximum available
Balance target0.45 – 0.50
Losing top speed on long straights → reduce rear aero 2–4 units · Corner instability → raise rear aero back up
Aero Balance Guide
Under 0.40Too rear — oversteer
0.40 – 0.45Slight rear — RWD friendly
0.45 – 0.50Neutral — ideal
Over 0.50Front bias — less oversteer
Brake — RWD
Balance55 – 60% front
Pressure90 – 100%
Rear locking under braking → raise front balance % · Front locking into corners → lower front balance %
Brake — AWD / FWD
AWD Balance52 – 56% front
FWD Balance58 – 65% front
Pressure90 – 100%
Rear locking (AWD) → lower front balance slightly · Rear stepping out (FWD) → raise front balance %
Differential Types
StockLow class / saves PI — limited or no tuning available
RaceCircuit & road racing — full accel/decel tuning range
DriftRoad drift — high lock bias, tuned for sustained slides
OffroadCross country / offroad drift — loose surface compliance
RallyMixed events — road & dirt compromise
DragStraight line only — maximum lock, launch focused
Unexpected handling → confirm Race diff is equipped before adjusting accel/decel
Differential — RWD
Acceleration35 – 55%
Deceleration15 – 30%
High power RWDAccel 50–60%
Wheelspin on exit → raise accel · Car snapping under trail braking → raise decel
Differential — AWD
Front
Acceleration15 – 25%
Deceleration5 – 10%
Rear
Acceleration40 – 55%
Deceleration20 – 30%
Center
Balance50 – 60% rear
AWD understeer → lower front accel · Exit wheelspin → raise rear accel · More rotation → shift center rearward
Handling Adjustments
  • Oversteer on exit (RWD)Lower diff accel / soften rear ARB
  • Understeer (AWD/FWD)Soften front ARB / stiffen rear ARB
  • Loose under brakingRaise diff decel / move brake bias forward
  • Poor turn-inMore front camber / increase front toe out
  • Rear sliding at speedIncrease rear downforce / stiffen rear ARB
  • Bouncy over bumpsLower bump damping on affected axle
Aero Balance Fix
  • Balance too low (<0.40)Raise front downforce to max first
  • Still too low after max frontLower rear downforce slightly
  • Understeer at speedReduce front downforce slightly
  • Oversteer at speedIncrease rear downforce
  • No aero optionsUse ARB & diff to compensate
Made by Caspeyy
Last updated: May 25, 2026