Lesson 9: Symptom Doctor

Tell it when the problem happens and what the car is doing. It gives you the fixes in the order to try them, with the reason for each and what you should feel. Every answer is also in the tables below, so the page works without JavaScript.

About 15 minutes, then keep it open as a reference
Works best with Fully Customizable Suspension and Fully Customizable LSD
Settings: every suspension and LSD setting, plus Downforce and Front/Rear Balance

Skip to the Doctor All fixes, phase by phase

How to use it: phase first, then symptom

You already know most of the fixes from the earlier lessons. The hard part on track is naming the problem precisely enough to pick the right one. "It understeers" isn't a diagnosis. "It understeers on entry to slow corners, as I come off the brakes" is, and it points to a very different fix from "it understeers on exit as I add power".

The Doctor asks two questions, in this order: when does it happen, and what is the car doing? Then, if you like, which wheels drive the car.

Step 1: name the phase

Pick the phase where the problem starts. A car that pushes on turn-in usually keeps pushing to the apex, and that's an entry problem, not a mid-corner one. Fix the first phase that goes wrong and the later ones often sort themselves out.

Three phases follow the corner; two can happen anywhere. Entry, mid-corner and exit are places on the racing line. High-speed and bumps or curbs are conditions: pick them when speed or the surface, rather than your pedals, sets the problem off.

Step 2: rule out the driver

Plenty of "setup problems" are input problems. Check these before you touch a slider:

Braking too late or too hard into the turn. An overloaded front tire can't steer, and that feels exactly like entry understeer.
Too much throttle, too early. On rear drive it looks like exit oversteer. On FF and 4WD it looks like exit understeer.
Adding steering lock as the car pushes. More lock past the limit just scrubs the front tires.
Lifting mid-corner. A lift moves weight off the rear and can turn a balanced car into a spinning one.
Cold or worn tires. Judge on warm tires, and expect the car to feel looser late in a long stint.

Every row in the tables below has a "Rule out first" line with the driving cause most likely to fake that symptom.

Step 3: confirm it over three laps

One lap is noise. If the same symptom shows up in the same phase, in the same kind of corner, for three laps in a row, it's the car. Write it down as phase + symptom + where, for example "entry understeer, slow corners, off the brakes". That sentence is your diagnosis, and it's what you feed the Doctor.

In GT7

Before a race you can also reach them from Quick Menu > Settings > Car Settings > Detailed Settings, but race regulations take priority there, so some options may be locked. Use Duplicate Sheet before you start fixing, so your baseline stays one tap away.

The fixes use these exact menu names: Body Height Adjustment, Natural Frequency, Damping Ratio (Compression), Damping Ratio (Expansion), Anti-Roll Bar, Negative Camber Angle and Toe Angle, each set separately for Front and Rear. On the diff side: Initial Torque, Acceleration Sensitivity and Braking Sensitivity, plus Front/Rear Torque Distribution on 4WD cars. Every car has its own slider ranges, so the step sizes below are starting points.

Requires Fully Customizable Suspension for the suspension fixes and the Fully Customizable LSD (selected as Fully Customized under Differential Gear Selection) for the diff fixes. Front/Rear Torque Distribution needs the Torque-Vectoring Center Differential on a 4WD car. Front/Rear Balance appears once Brake Balance Selection is set to Brake Controller. Downforce only helps on cars where it is adjustable. Race cars such as Gr.3 and Gr.4 usually have the suspension and LSD settings already.

Why the fixes come in this order

Every list puts the cheapest, safest change first. "Cheap" means it acts mainly in the phase you're fixing and leaves the rest of the lap alone. "Safe" means a step too far is easy to feel and easy to undo.

The diff. Braking Sensitivity only acts off-throttle and Acceleration Sensitivity only on throttle, so each one targets a single phase. Initial Torque acts everywhere, so it comes after them.
Dampers. They change how fast weight moves, not where it ends up, so they shape the transitions on entry and exit. Less Damping Ratio (Compression) Front lets weight reach the front tires sooner under braking. More Damping Ratio (Expansion) Rear keeps the rear loaded for longer.
Springs and ride height. Natural Frequency and Body Height Adjustment change the car in every phase and on every surface, and stiffening can move your PP. They're powerful but blunt.
Anti-roll bars. GT7's own magazine calls them "a final tuning tool". They fine-tune balance once the springs are right.
Camber and toe. Small, precise trims for the last bit of balance or stability. Toe Angle moves in hundredths of a degree.

Front/Rear Balance appears in the braking rows and Downforce in the high-speed rows, because those are the only phases where they do much.

Exceptions you'll see in the tables

High-speed corners: aero and toe come first. In a long, steady fast corner the diff barely differentiates and the dampers barely move, so Downforce and Toe Angle Rear do the work.
Scraping and bottoming: ride height comes first. Clearance is the problem, and a steady downforce load is something dampers can't hold off.
FF entry rotation: the front diff can't help a front-drive car turn in, and FF baselines already run little braking lock. So the rear does the steering. Stiffen the Anti-Roll Bar Rear or lower the Damping Ratio (Expansion) Rear, and the tail helps rotate the car on entry. The front is left alone, so it keeps its grip.
RWD exit oversteer: the rear diff is the main lever. Lower Acceleration Sensitivity, then soften the Anti-Roll Bar Rear so the inside rear keeps its load. The front is untouched, so turn-in stays the same.
RWD exit understeer: GT7's official fix is a slightly lower front plus damper changes, so lower Body Height Adjustment Front comes first. Less Acceleration Sensitivity helps only when a heavily locked rear pushes on part throttle.
FF exit understeer: the opposite of RWD. A little more Acceleration Sensitivity stops the inside front spinning, but too much ties the steering wheels together and the push comes back.
4WD: Front/Rear Torque Distribution moves the whole car's character. Toward the rear it behaves more like rear drive and rotates; toward 50:50 it gets more stable and pushes more.

Rule of thumb

One change, one step, three laps. If the symptom gets smaller and nothing new appears, keep it. If it gets smaller but the other end of the car starts to misbehave, you went a step too far: go back halfway.

What "one step" means (a sensible first try)
Setting	Unit	One step	Notes
Body Height Adjustment	mm	3–5 mm	2–3 mm for rake tweaks. Lower is generally better until the car scrapes.
Natural Frequency	Hz	0.1–0.2 Hz	The manual puts road cars around 1.1–1.5 Hz and race cars around 3–5 Hz, so the same step means more on a road car.
Damping Ratio (Compression)	%	3–5 points	About 20–40 % on most cars. Keep it below expansion.
Damping Ratio (Expansion)	%	3–5 points	About 30–50 % on most cars.
Anti-Roll Bar	level	1	1–10 on most cars. The final balance tool.
Negative Camber Angle	°	0.3°	More helps cornering grip and costs braking grip and tire wear.
Toe Angle	°	0.02–0.05°	Slider right is toe-in, left is toe-out. Change it last.
Initial Torque	value	3–5	Typically 5–60. Acts in every phase.
Acceleration Sensitivity	value	5	Typically 5–60. On throttle only.
Braking Sensitivity	value	5	Typically 5–60. Off throttle and under braking only.
Front/Rear Torque Distribution	F:R	5 (40:60 to 35:65)	4WD with the Torque-Vectoring Center Differential.
Downforce	value	One small step	Range is per car. More grip, less top speed.
Front/Rear Balance	step	1	Needs Brake Controller. Verify the direction with a quick test.

Common mistake

Fixing the phase where you notice the problem instead of the phase where it starts. Entry understeer that carries to the apex looks like a mid-corner push, so you soften the Anti-Roll Bar Front, the car gets lazy everywhere, and turn-in is still bad. Ask yourself whether it was already wrong before the apex. If so, start in the Braking / entry table.

Every fix, phase by phase

One table per phase and one row per symptom, with fixes in the order to try them. Lines tagged with a drivetrain apply only to that layout. A "Try first" tag means the fix jumps to the top of the list for that drivetrain. Where a line says "at the end that hits", pick the Front or Rear setting to match.

Braking / entry

From the brake point to turn-in, and off the brakes toward the apex.

Braking / entry: every fix, in the order to try it
Symptom	Try, in this order
Understeer The nose won't turn in as you come off the brakes. Rule out first: Braking too late, or still braking hard while you add steering. Brake a little earlier and ease off the pedal as you turn.	RWD and FF only Lower Braking Sensitivity by 5. Why: Off-throttle lock ties the driven wheels together, and an axle that can't differentiate resists turning. You'll feel: The nose bites as you release the brake. The car feels a little livelier on turn-in. 4WD only, try first Lower Braking Sensitivity Front by 5. Why: On 4WD the front diff decides turn-in. Milder front locking is the standard approach. You'll feel: Freer steering on entry while the rear diff still steadies the car. RWD only On Two-Way LSD: switch Differential Gear Selection to One-Way LSD. Why: A one-way diff doesn't lock off-throttle at all, which is the official cure for RWD entry understeer. You'll feel: Easier turn-in. Slightly less stability under very hard braking. Lower Damping Ratio (Compression) Front by 3–5. Why: The nose dips faster under braking, so weight reaches the front tires sooner. You'll feel: Quicker front bite at turn-in, with a little more dive. Try first on FF Stiffen Anti-Roll Bar Rear by 1. Why: Moves grip away from the rear so the car rotates. On FF it's the main entry lever, because the front diff can't help the car turn. You'll feel: The tail helps steer the car into the corner. Too much and it steps out on the brakes. FF only, try first Lower Damping Ratio (Expansion) Rear by 3–5. Why: The rear rises faster as weight moves forward, so it unloads and lets the car rotate. You'll feel: The rear follows the nose round on brake release. Lower Initial Torque by 3–5. Why: Less preload means less lock everywhere. It helps turning, but it also changes exit, so recheck that. You'll feel: Freer rotation into the corner, with slightly less drive out of it. Move Front/Rear Balance toward the rear by 1 step. Why: A little more rear braking helps the car rotate as you turn in. The menu's own wording on this is confusing, so verify with a quick test. You'll feel: The car rotates on the brakes. Go too far and the Rear gets light. Soften Natural Frequency Front by 0.1–0.2 Hz. Why: A softer front takes the weight transfer more gently and grips more on entry. You'll feel: Softer, more progressive turn-in, with a bit more body movement.
Oversteer The rear steps out under braking or as you turn in. Rule out first: Trail-braking too deep, turning at full brake pressure, or downshifting so early that engine braking upsets the rear.	RWD and 4WD only Raise Braking Sensitivity by 5 (on 4WD, the Rear diff). On One-Way LSD, Two-Way LSD does the same job. Why: Off-throttle lock holds the rear wheels together, which steadies the car on the brakes and on entry. You'll feel: A calmer Rear on entry. The car turns in a little less eagerly. RWD and 4WD only If it happens the instant you lift off the throttle: Lower Acceleration Sensitivity by 5. Why: GT7's manual warns that high Acceleration Sensitivity can make the car unstable when you release the throttle. You'll feel: A smoother lift with the rear staying put. Try first on FF Raise Damping Ratio (Expansion) Rear by 3–5. Why: The rear rises more slowly as weight goes forward, so the rear tires keep their load longer. You'll feel: A planted Rear on brake release, with slightly lazier rotation. Move Front/Rear Balance toward the front by 1 step. Why: More front braking leaves the rear tires grip to spare for cornering. The menu's own wording on this is confusing, so verify with a quick test. You'll feel: Steadier braking, with a touch more understeer at turn-in. Try first on FF Soften Anti-Roll Bar Rear by 1. Why: A softer rear bar shares the rear load across both rear tires. You'll feel: The rear takes a set instead of snapping round. Move Toe Angle Rear toward toe-in by 0.02–0.05°. Why: Rear toe-in is the stability setting. Change it last, in tiny steps. You'll feel: A steadier rear, with slightly slower rotation everywhere.
Unstable / nervous The car squirms, wanders or darts under hard braking, even in a straight line. Rule out first: Braking over bumps, or braking with the wheel still turned. Brake in a straight line with the wheel straight, then test again.	RWD and 4WD only Raise Braking Sensitivity by 5. Why: Locks the rear axle together so one rear wheel can't slow more than the other. You'll feel: The car tracks straight while you brake. Move Front/Rear Balance toward the front by 1 step. Why: Rear tires that brake less have more grip left for keeping the car straight. The menu's own wording on this is confusing, so verify with a quick test. You'll feel: Calmer braking, with a little more understeer at turn-in. Raise Damping Ratio (Compression) Front by 3–5. Why: Slows the dive, so the car pitches less and the rear stays loaded. It costs some front bite, the opposite of the entry understeer fix. You'll feel: Less nose dive and a flatter, calmer car under braking. Move Toe Angle Rear toward toe-in by 0.02–0.05°. Why: Rear toe-in adds straight-line stability. You'll feel: The rear stops wriggling under heavy braking. If you run front toe-out: Move Toe Angle Front toward toe-in by 0.02° (toward zero). Why: Front toe-out sharpens turn-in but makes the car darty in a straight line. You'll feel: Calmer steering on the brakes, with slightly lazier turn-in. If the nose sits well below the tail: Raise Body Height Adjustment Front by 2–3 mm. Why: Lowering the front unloads the rear and adds an oversteer tendency, so less rake calms the rear. You'll feel: A more settled Rear when you brake hard.
Wheelspin Under braking this is almost always a wheel locking, not spinning: smoke, a judder, or a car that won't steer. Rule out first: Braking too hard for the grip, or not releasing as you turn. A locked tire can't steer. Brake earlier and bleed off pressure as you add steering.	If the fronts lock: Move Front/Rear Balance toward the rear by 1 step. Why: Moves braking work to the end that has grip to spare. The menu's own wording on this is confusing, so verify with a quick test. You'll feel: No more front lock-ups. The car may rotate more on entry. If the rears lock: Move Front/Rear Balance toward the front by 1 step. Why: Takes braking work away from the rear tires before they lock. The menu's own wording on this is confusing, so verify with a quick test. You'll feel: No rear lock-ups, and a more stable but slightly pushier entry. If it locks over bumps: Lower Damping Ratio (Compression) by 3–5 at the end that locks (Front or Rear). Why: A tire skipping over a bump carries no load and locks instantly. Softer compression keeps it on the road. You'll feel: Fewer lock-ups in bumpy braking zones. RWD and 4WD only If only the inside rear chatters or locks on turn-in: Raise Braking Sensitivity by 5. Why: Off-throttle lock ties the light inside rear to the loaded outside rear, so engine braking can't stop it on its own. You'll feel: A smoother entry with no rear chatter.
Bouncing / bottoming The nose hits the ground, scrapes, or pitches hard under braking. Rule out first: One braking zone with a dip or bump in it? That may be the track, not the car. Check it happens in more than one place.	Raise Damping Ratio (Compression) Front by 3–5. Why: Slows the dive so the nose uses less travel. You'll feel: Flatter braking, with slightly less front bite at turn-in. If the nose keeps bobbing after you release the brake: Raise Damping Ratio (Expansion) Front by 3–5. Why: Slower rebound lets the front settle in one motion. You'll feel: The nose settles once instead of bouncing. Raise Body Height Adjustment Front by 3–5 mm. Why: More clearance before the nose touches down. Raising the front also adds a little understeer. You'll feel: No scraping. Turn-in may be slightly lazier. Stiffen Natural Frequency Front by 0.1–0.2 Hz. Why: A stiffer front uses less travel for the same load, but grips a little less. You'll feel: A firmer nose, with a touch more understeer.

Mid-corner

Around the apex, on a steady or light throttle.

Mid-corner: every fix, in the order to try it
Symptom	Try, in this order
Understeer The car pushes wide at the apex on a steady or light throttle. Rule out first: Too much entry speed, or adding steering lock as it pushes (that just scrubs the front tires). Slow in, then judge.	Lower Initial Torque by 3–5 (on 4WD, start with the Front diff). Why: At a steady throttle, preload is the only lock working, and the manual says it can hinder turning. You'll feel: The car turns more freely at the apex, with slightly less drive out. 4WD only, try first Shift Front/Rear Torque Distribution toward the rear by 5 (for example 40:60 to 35:65). Why: More rear torque moves a 4WD car toward rear-drive behavior. Toward 50:50 does the opposite. You'll feel: The car rotates on light throttle instead of pushing. Raise Negative Camber Angle Front by 0.3°. Why: Keeps the loaded outside front tire flatter as the car rolls, which is the official apex fix. You'll feel: More front grip held through the apex. Braking may get slightly longer. Soften Natural Frequency Front by 0.1–0.2 Hz. Why: A stiffer front slides first, so softening it shifts the balance rearward. You'll feel: The nose holds the line, with a bit more roll. Soften Anti-Roll Bar Front by 1. Why: The stiffer end of the car runs out of grip first. This is the final balance tweak. You'll feel: Slightly lazier first turn-in, then the nose holds the line. FF only, try first Stiffen Anti-Roll Bar Rear by 1. Why: On FF the front tires already steer and drive. Freeing up the rear rotates the car without taking anything from the front. You'll feel: The tail helps the car around the apex. Move Toe Angle Rear toward toe-out by 0.02° (less toe-in). Why: Less rear toe-in gives more rotation. Keep some, because it is your high-speed stability. You'll feel: The car rotates more. Watch for a lighter rear in fast corners.
Oversteer The rear slides at the apex on a steady throttle. Rule out first: Lifting mid-corner, or adding more steering. Hold a steady throttle and smooth steering for a full lap, then judge.	RWD and 4WD only Lower Initial Torque by 3–5 (on 4WD, the Rear diff). Why: Preload accentuates a layout's natural tendency, and on a driven rear axle that tendency is oversteer. You'll feel: A calmer Rear at the apex. 4WD only, try first Shift Front/Rear Torque Distribution toward 50:50 by 5 (for example 35:65 to 40:60). Why: More front torque pulls a 4WD car toward stable understeer. You'll feel: The car stays straighter on throttle and pushes a little more. Soften Anti-Roll Bar Rear by 1. Why: A softer rear bar shares load across both rear tires, so the rear grips longer. You'll feel: The rear takes a set and stays there. Soften Natural Frequency Rear by 0.1–0.2 Hz. Why: A stiffer rear slides first. Softening it moves the balance forward. You'll feel: A more forgiving rear, with slightly more squat and roll. Move Toe Angle Rear toward toe-in by 0.02–0.05°. Why: Rear toe-in steadies the rear axle. You'll feel: The rear feels planted. Rotation slows a touch. Only if the front is much softer than the rear: Stiffen Natural Frequency Front by 0.1 Hz. Why: A very soft front lets the car roll onto its rear. Bringing the ends closer evens it out. You'll feel: A flatter car with a slightly less eager nose.
Unstable / nervous The balance flicks between push and slide, and small inputs upset the car. Rule out first: Sawing at the wheel or feathering the throttle. Hold steady inputs for a lap before blaming the setup.	If it twitches as you ease off the throttle: Lower Acceleration Sensitivity by 5. Why: High Acceleration Sensitivity can make the car unstable when you release the throttle (GT7 manual). You'll feel: Small throttle changes stop upsetting the car. Raise Damping Ratio (Expansion) Rear by 3–5. Why: More rebound damping settles the car after a weight shift and gives a stable tendency. You'll feel: The car settles into one attitude instead of rocking between two. Move Toe Angle Rear toward toe-in by 0.02–0.05°. Why: Rear toe-in calms the rear axle's response to small inputs. You'll feel: Less twitch. Slightly slower rotation. Bring Natural Frequency Front and Rear closer together (within about 0.2 Hz) by moving the higher one down. Why: The manual says matched front and rear frequencies give a smoother ride, so the ends don't pitch out of step. You'll feel: A calmer car over undulations, with a more predictable balance. Soften Anti-Roll Bar Rear by 1. Why: A rear bar much stiffer than the springs makes the rear react sharply to every load change. You'll feel: A more progressive rear.
Wheelspin The inside driven wheel spins at the apex on part throttle. Revs flare and drive drops. Rule out first: Adding throttle before the car has turned. Wait until you can start unwinding the wheel.	If Differential Gear Selection reads Normal: fit the Fully Customizable LSD and select Fully Customized. Why: An open diff gives both wheels the same torque, so the light inside wheel caps the drive. Many cars' standard diff behaves close to open. You'll feel: Drive that keeps pulling through the apex instead of flaring revs. Raise Initial Torque by 3–5. Why: Preload engages the lock sooner, so torque reaches the loaded outside wheel. It also accentuates the layout's tendency. You'll feel: Steady drive at the apex. A little more push on FF, a little more rotation on RWD. Raise Acceleration Sensitivity by 5. Why: More lock under throttle stops the inside wheel spinning away. You'll feel: Cleaner drive as you squeeze the throttle. The car is harder to place on exit. RWD only Soften Anti-Roll Bar Rear by 1. Why: A bar much stiffer than the springs lifts the inside rear wheel off the road. You'll feel: The inside rear stays down and keeps driving. FF only Soften Anti-Roll Bar Front by 1. Why: A stiff front bar lifts the inside front, the wheel that's trying to drive. You'll feel: Less inside-front spin, and a little more front grip. 4WD only Soften Anti-Roll Bar by 1 at the end whose inside wheel spins (Front or Rear). Why: A bar much stiffer than the springs lifts the inside wheel. You'll feel: The spinning wheel stays planted.
Bouncing / bottoming The car scrapes or bottoms out in long corners, or hops across the surface. Rule out first: One corner with a bump in it? Check the Bumps / curbs table too.	If it scrapes or bottoms: Raise Body Height Adjustment by 3–5 mm at the end that hits (Front if the nose, Rear if the tail). Why: More clearance under roll. Raising one end shifts balance a little: a higher front adds understeer, a higher rear adds rotation. You'll feel: No more scraping in long corners. If it scrapes: Raise Damping Ratio (Compression) by 3–5 at the end that hits. Why: Slows the body rolling onto that end and cuts the overshoot past its settled position. It can't help once the car has settled; that needs height or springs. You'll feel: A firmer, flatter entry into long corners. If it hops or skips across the surface: Soften Anti-Roll Bar by 1 at the end that hops. Why: Bars much stiffer than the springs unload the inside wheel and make the car skip. You'll feel: The car stays in contact and stops skating. If it scrapes and the car runs downforce: Stiffen Natural Frequency by 0.1–0.2 Hz at the end that hits. Why: Downforce compresses the springs. The official advice is to raise Natural Frequency for downforce cars. You'll feel: Steady ride height at speed. The ride gets a little firmer.

Exit / throttle

From the moment you add throttle until the car is straight.

Exit / throttle: every fix, in the order to try it
Symptom	Try, in this order
Understeer The car runs wide as you add throttle. Rule out first: Flooring it before the apex, or not unwinding the wheel. Squeeze the throttle as you open the steering.	Try first on RWD Lower Body Height Adjustment Front by 2–3 mm. Why: Official advice for RWD exit understeer. On FF it also counters the nose lifting under acceleration. You'll feel: Better front grip on exit. Check that the Rear is still calm on entry. FF only, try first Raise Acceleration Sensitivity by 5, but stop when the steering goes heavy and the car pulls straight. Why: On FF, more lock stops the inside front spinning so the front can pull you round. Too much worsens the push (official advice). You'll feel: The inside front stops spinning and the car drives out on its line. 4WD only, try first Shift Front/Rear Torque Distribution toward the rear by 5. Why: Less torque through the steering wheels frees the front, and more rear torque helps the car rotate on power. You'll feel: The car turns on throttle instead of washing wide. 4WD only Lower Acceleration Sensitivity Front by 5. Why: Milder front locking keeps the front wheels free to steer under power. You'll feel: Lighter, more accurate steering on exit. Raise Damping Ratio (Expansion) Front by 3–5. Why: The nose rises more slowly as weight moves back, so the front tires keep load longer as you accelerate. You'll feel: The front holds its line for the first part of the throttle. RWD only If it pushes on part throttle and the rear never steps out: Lower Acceleration Sensitivity by 5. Why: Before the rear tires reach their limit, a heavily locked rear axle drives both wheels at one speed and resists rotation. Past the limit the same lock gives power oversteer instead (Lesson 6), so change it one step at a time. You'll feel: The car turns more willingly on part throttle. The inside rear may spin a little more. Soften Anti-Roll Bar Front by 1. Why: The final balance tweak: the stiffer end slides first. You'll feel: The nose holds a tighter line out of the corner.
Oversteer The rear steps out as you add throttle. Rule out first: Adding throttle with lots of steering still on, or stabbing the pedal. Squeeze it in as you unwind.	RWD only, try first Lower Acceleration Sensitivity by 5. Why: On rear drive, heavy lock under power drives both rear tires to the limit together, which accentuates oversteer. You'll feel: The rear stays behind you. The inside rear may chirp a little instead. Try first on RWD Soften Anti-Roll Bar Rear by 1. Why: The inside rear keeps more load, so the axle has more grip to put power down. You'll feel: The rear squats and drives instead of stepping out. 4WD only, try first Shift Front/Rear Torque Distribution toward 50:50 by 5. Why: More front torque pulls the car out of the corner instead of pushing it from behind. You'll feel: A stable, slightly pushier exit. 4WD only Lower Acceleration Sensitivity Rear by 5. Why: Less rear lock under power, for the same reason as on RWD. You'll feel: A calmer rear on throttle. RWD and 4WD only Lower Initial Torque by 3–5. Why: Preload accentuates a rear-drive car's oversteer tendency. You'll feel: A gentler rear as the lock comes in. Lower Damping Ratio (Compression) Rear by 3–5. Why: The rear squats onto its tires faster as you accelerate, building traction sooner. You'll feel: An earlier, smoother bite out of slow corners. Soften Natural Frequency Rear by 0.1–0.2 Hz. Why: A softer rear grips longer when weight comes onto it. You'll feel: More rear traction. The car feels slightly softer under acceleration.
Unstable / nervous The car snaps between push and slide as you modulate the throttle, or twitches on the way out. Rule out first: On and off the throttle. Commit to one smooth squeeze for three laps.	Lower Acceleration Sensitivity by 5. Why: The manual warns that high Acceleration Sensitivity makes the car unstable when you release the throttle. You'll feel: Small lifts on exit stop upsetting the car. RWD and 4WD only Lower Initial Torque by 3–5. Why: Less preload makes the lock come in more gradually instead of all at once. You'll feel: A smoother transition from coasting to drive. Move Toe Angle Rear toward toe-in by 0.02–0.05°. Why: Rear toe-in steadies the rear axle. You'll feel: Less twitch as the power goes down. Soften Anti-Roll Bar Rear by 1. Why: A softer rear bar makes the rear react more progressively to throttle changes. You'll feel: A rear that warns you before it slides.
Wheelspin The driven wheels spin as you power out: one wheel (the inside) or both. Rule out first: Flooring it in a low gear before the car is straight. Roll the throttle in.	If Differential Gear Selection reads Normal: fit the Fully Customizable LSD and select Fully Customized. Why: An open diff gives both wheels the same torque, so the wheel with the least grip sets the limit. You'll feel: The car finally drives out instead of spinning one wheel. If only the inside wheel spins: Raise Acceleration Sensitivity by 5. Why: More lock under throttle sends torque to the loaded outside wheel. This is the official exit-traction fix. You'll feel: Strong, straight drive out of slow corners. If only the inside wheel spins: Raise Initial Torque by 3–5. Why: Preload engages the lock sooner, so less torque escapes through the inside wheel. You'll feel: Drive from the first touch of throttle. RWD only Soften Anti-Roll Bar Rear by 1. Why: A stiff rear bar lifts the inside rear, so it spins. You'll feel: Both rear tires stay planted. RWD only If both rears spin: Lower Damping Ratio (Compression) Rear by 3–5. Why: Weight settles onto the rear tires faster as you accelerate. You'll feel: The rear squats and hooks up sooner. RWD only If both rears spin: Soften Natural Frequency Rear by 0.1–0.2 Hz. Why: A softer rear lets the tires take the weight transfer and grip. You'll feel: More traction, slightly more squat. FF only Soften Anti-Roll Bar Front by 1. Why: A stiff front bar lifts the inside front, the wheel trying to drive. You'll feel: Less inside-front spin out of hairpins. FF only Lower Body Height Adjustment Front by 2–3 mm. Why: A slightly lower nose counters the front lifting under acceleration (official advice for FF). You'll feel: The front stays loaded as you accelerate. 4WD only, try first If the rears spin: Shift Front/Rear Torque Distribution toward 50:50 by 5. Why: Sends more torque to the front tires, which have grip to spare. You'll feel: Cleaner launches out of slow corners, with a little more push.
Bouncing / bottoming The tail squats and scrapes under power, or the car hops as you accelerate over bumps. Rule out first: Full throttle over a rough exit? Some hop on one bad patch is the track. Look for it in several corners.	If the tail scrapes: Raise Damping Ratio (Compression) Rear by 3–5. Why: Slows the squat, so the rear uses less travel. You'll feel: Flatter acceleration, with slightly less rear bite at first. If it hops over bumps under power: Raise Damping Ratio (Expansion) by 3–5 on the driven axle (Rear on RWD, Front on FF, both on 4WD). Why: More rebound damping stops the driven axle oscillating after each bump. You'll feel: The car settles after one bump instead of hopping. If the tail scrapes: Raise Body Height Adjustment Rear by 3–5 mm. Why: More clearance at the back. Raising the rear moves balance slightly toward rotation. You'll feel: No scraping. The car may rotate a touch more. If it still bottoms: Stiffen Natural Frequency Rear by 0.1–0.2 Hz. Why: A stiffer rear uses less travel under squat, at some cost to traction. You'll feel: A firmer rear with less squat.

High-speed

Fast sweepers, kinks and straights, where aero does much of the work. No adjustable aero on your car? Skip the Downforce lines.

High-speed: every fix, in the order to try it
Symptom	Try, in this order
Understeer The car pushes in fast sweepers and kinks. Rule out first: Turning in early in fast corners, or lifting so the nose goes light. Commit to a steady throttle through the corner.	Add Downforce Front by one small step (or take one off the Rear). Why: Aero is the main lever at speed. More front downforce means more front grip (official advice). You'll feel: A sharper nose in fast corners, and a little less top speed. Lower Body Height Adjustment Front by 2–3 mm. Why: A slightly lower front gives more front grip and sharper turn-in, and it also shifts the aero balance. You'll feel: The nose bites in fast corners. Check that the rear is still calm under braking. Soften Anti-Roll Bar Front by 1. Why: The stiffer end slides first. It helps in fast corners, and in slow ones too. You'll feel: The nose holds a tighter line in long fast corners. Raise Negative Camber Angle Front by 0.3°. Why: Keeps the outside front flatter under sustained load. You'll feel: More front grip in long corners. Braking may get slightly longer.
Oversteer The rear feels light or slides in fast corners. Rule out first: Lifting mid-corner at speed. A lift shifts weight off the rear. Stay on a steady throttle.	Add Downforce Rear by one small step. Why: More rear downforce means more rear grip at speed (official advice). You'll feel: A planted rear through fast corners, and a little less top speed. Move Toe Angle Rear toward toe-in by 0.02–0.05°. Why: Rear toe-in is the official high-speed stability setting. You'll feel: The rear stops floating. Slightly slower rotation in slow corners. Lower Body Height Adjustment Rear by 2–3 mm (less rake). Why: Lowering the rear gives an understeer tendency and shifts the aero balance. You'll feel: A more planted rear at speed, with slightly lazier turn-in. Soften Anti-Roll Bar Rear by 1. Why: A softer rear bar shares the load across both rear tires. You'll feel: The rear takes a set instead of stepping out.
Unstable / nervous The car wanders or darts on straights and kinks. Small steering inputs feel big. Rule out first: Over-correcting. Hold the wheel lightly on the straight first and see if it settles.	Move Toe Angle Rear toward toe-in by 0.02–0.05°. Why: Rear toe-in gives straight-line and high-speed stability. You'll feel: The car tracks straight with less steering correction. If you run front toe-out: Move Toe Angle Front toward toe-in by 0.02° (toward zero). Why: Front toe-out sharpens turn-in but makes the car darty at speed. You'll feel: Calmer steering on the straights. Add Downforce Rear by one small step. Why: More rear grip at speed steadies the car. You'll feel: A planted rear, and a little less top speed. If the nose sits well below the tail: Raise Body Height Adjustment Front by 2–3 mm. Why: Big rake unloads the rear and moves aero balance forward, which makes the car nervous at speed. You'll feel: A calmer car on fast straights and kinks.
Wheelspin The driven wheels spin in higher gears: over crests, on fast exits, or in the wet. Rule out first: Rain, or cold or worn tires. Check the conditions before touching the setup.	If one wheel spins on a fast exit: Raise Acceleration Sensitivity by 5. Why: More lock under throttle sends drive to the loaded wheel. You'll feel: Clean drive out of fast corners. If it spins over crests: Lower Damping Ratio (Expansion) by 3–5 on the driven axle (Rear on RWD, Front on FF, both on 4WD). Why: Less rebound damping lets the wheel drop back onto the road faster as the car goes light. You'll feel: Less spin as you crest a rise. The car moves around a little more. RWD and 4WD only Add Downforce Rear by one small step. Why: More rear load at speed means more rear traction. You'll feel: The rear hooks up in fast exits, with a little less top speed. Soften Natural Frequency by 0.1–0.2 Hz on the driven axle (Rear on RWD, Front on FF, both on 4WD). Why: A softer driven axle keeps its tires in contact over undulations. You'll feel: Smoother traction over crests, with slightly more body movement. 4WD only If the rears spin: Shift Front/Rear Torque Distribution toward 50:50 by 5. Why: Shares more torque with the front tires. You'll feel: Steadier traction, with a little more push.
Bouncing / bottoming The car scrapes or bottoms at top speed, or keeps bouncing after a crest. Rule out first: One compression or dip on one track? A single scrape there may be fine. Repeated bottoming isn't.	Raise Body Height Adjustment by 3–5 mm at the end that scrapes (Front or Rear). Why: Downforce is a steady load that dampers can't resist. Only clearance or stiffer springs fix it, so here height comes first. You'll feel: No more scraping at speed. Raising one end shifts the aero balance a little. Stiffen Natural Frequency by 0.1–0.2 Hz at the end that scrapes. Why: The official advice is to raise Natural Frequency for downforce cars. You'll feel: Steady ride height at speed. Firmer over bumps. Raise Damping Ratio (Compression) by 3–5 at the end that scrapes. Why: Slows the body diving onto that end over dips and compressions. You'll feel: Less crashing through compressions. If it keeps bouncing after a crest: Raise Damping Ratio (Expansion) Front and Rear by 3–5. Why: More rebound damping stops the body oscillating. You'll feel: One clean landing instead of several bounces.

Bumps / curbs

Whenever the road surface, not your inputs, sets the problem off.

Bumps / curbs: every fix, in the order to try it
Symptom	Try, in this order
Understeer The front skips or washes wide over bumps, or when you clip a curb. Rule out first: Taking more curb than the car can swallow. Try a lap with less curb first.	Lower Damping Ratio (Compression) Front by 3–5. Why: The front wheels can rise over a bump without throwing the tire off the road. You'll feel: The nose rides the curb instead of skipping off it. Soften Anti-Roll Bar Front by 1. Why: A curb hits one side. The bar is what carries that hit across to the other wheel. You'll feel: One-wheel hits upset the front less. Soften Natural Frequency Front by 0.1–0.2 Hz. Why: A softer spring keeps the front tire pressed on the road over rough ground. You'll feel: A more compliant front, with a bit more roll. If the nose also bottoms: Raise Body Height Adjustment Front by 3–5 mm. Why: More travel before the body hits the ground. You'll feel: No more front scraping over bumps.
Oversteer The rear kicks out over bumps, or when the rear wheels hit a curb. Rule out first: Full throttle on the exit curb. Ease in until the rear wheels are off it.	Lower Damping Ratio (Compression) Rear by 3–5. Why: The rear wheels can rise over the bump while the tires keep their grip. You'll feel: The rear rides over curbs instead of being kicked sideways. If the rear stays light after the bump: Lower Damping Ratio (Expansion) Rear by 3–5. Why: Too much rebound damping stops the wheel dropping back down, so the tire hangs in the air. Note that less rear rebound also adds rotation elsewhere. You'll feel: The rear lands and grips again sooner. Soften Anti-Roll Bar Rear by 1. Why: A one-side hit on a stiff bar unloads the other rear wheel too. You'll feel: Curbs upset the rear less. Soften Natural Frequency Rear by 0.1–0.2 Hz. Why: A softer rear keeps its tires in contact over rough ground. You'll feel: A calmer, more forgiving rear.
Unstable / nervous The car crashes, skips sideways or gets knocked off line over bumpy sections. Rule out first: Hitting the same bump every lap? Moving your line by a car width may cure it.	Lower Damping Ratio (Compression) Front and Rear by 3–5. Why: Lets the wheels follow the road instead of launching the body. Change both ends by the same amount to keep the balance. You'll feel: Bumps feel rounded off, and the car stays on its line. Soften Anti-Roll Bar Front and Rear by 1. Why: Softer bars stop one-wheel hits spreading across each axle. You'll feel: Less side-to-side kick over bumps. Soften Natural Frequency Front and Rear by 0.1–0.2 Hz. Why: Stiffer isn't always better: the official magazine warns that tires lose contact over bumps. You'll feel: A more compliant car with more body movement. Raise Body Height Adjustment Front and Rear by 3–5 mm. Why: More travel before anything hits the ground. You'll feel: No more crashing over the worst bumps, at a small cost to center-of-gravity height.
Wheelspin A driven wheel goes light over a bump or curb and spins up. Rule out first: Full throttle over the curb. Wait until you're off it, or short-shift.	Raise Initial Torque by 3–5. Why: Preload keeps sending drive to the wheel that's still on the ground. You'll feel: Steady drive when one wheel goes light. Lower Damping Ratio (Compression) by 3–5 on the driven axle (Rear on RWD, Front on FF, both on 4WD). Why: The driven wheel follows the bump instead of bouncing off it. You'll feel: Fewer flare-ups over curbs. Soften Anti-Roll Bar by 1 on the driven axle (Rear on RWD, Front on FF, both on 4WD). Why: A one-side curb hit on a stiff bar lifts the other driven wheel. You'll feel: Both driven wheels stay down over curbs. Soften Natural Frequency by 0.1–0.2 Hz on the driven axle (Rear on RWD, Front on FF, both on 4WD). Why: Softer springs keep the driven tires in contact. You'll feel: Smoother traction over rough exits.
Bouncing / bottoming The car bottoms out over bumps, or keeps bouncing after them. Rule out first: Running a lot of curb, or one bad bump? Check it happens in several places.	If it keeps bouncing after the bump: Raise Damping Ratio (Expansion) by 3–5 at that end (Front or Rear). Why: Rebound damping is what stops the oscillation after the hit. You'll feel: One clean movement over the bump, then calm. If it bottoms: Raise Body Height Adjustment by 3–5 mm at the end that hits. Why: Clearance is the direct fix for bottoming. You'll feel: No more scraping. If it bottoms: Raise Damping Ratio (Compression) by 3–5 at the end that hits. Why: Slows the suspension on the way in, so it uses less travel. You'll feel: Firmer over big bumps, without changing the springs. If height alone doesn't fix it: Stiffen Natural Frequency by 0.1–0.2 Hz at the end that hits. Why: A stiffer spring uses less travel, at some cost to grip over small bumps. You'll feel: A firmer ride and steadier ride height.

When to stop

Tuning goes wrong when changes pile up. Each one shifts the balance a little, and after five or six you can't tell which change caused what. So give yourself a limit: three changes for one symptom. If none of them helped, the problem isn't where you think it is.

Three strikes, back to baseline. Undo a change that didn't help before you try the next one, so you only ever test one thing against the baseline.

What to do when you hit the limit

Reload the baseline sheet. Go back to the copy you made with Duplicate Sheet. Don't try to unpick three changes from memory.
Re-diagnose from scratch. Drive three laps and ask the phase question again. The most common miss is an entry problem being treated as a mid-corner or exit one.
Check the things that aren't suspension. Front and rear tires are chosen separately: a softer compound at one end changes the balance more than any slider. Cold tires, a heavy fuel load and track rubber all change the feel too.
Check the baseline itself. If the car is far off before you start, for example Natural Frequency wildly mismatched between Front and Rear, or race-car stiffness on comfort tires, go back to Lesson 8 and rebuild it.

Note

Suspension changes, stiffening in particular, can move the car's PP. If PP shows a "!" after your edits, press Triangle in Car Settings to recalculate it before you enter a PP-limited event.

Common mistake

Fixing both ends at once. You soften the Front bar and stiffen the Rear bar for mid-corner understeer, and now the car oversteers. You can't tell which change was too much. Move one end, test, then decide on the other.

Try it on track

Any car you've tuned to a baseline, with Fully Customizable Suspension and the Fully Customizable LSD. Pick a technical track with at least two slow corners and one fast one, and duplicate your settings sheet first.

Drive three clean laps on the baseline. Note your worst problem as phase + symptom + where.
Enter it in the Doctor (or find its row in the tables) with your drivetrain. Make fix 1 only, by exactly the step it lists. Change nothing else.
Drive three more laps and focus on the same corners and the same phase.

What you should feel: the symptom gets smaller in that one phase while the other phases feel the same. If the problem moves to the other end of the car, for example entry understeer becomes a loose Rear on the brakes, the fix works but the step was too big: go back halfway.

Key takeaways

Diagnose the phase first, and pick the phase where the problem starts, not where you notice it.
Rule out driving causes, then confirm the symptom over three laps before changing anything.
Try the cheapest, most targeted fix first: diff and dampers before springs, with bars and toe as fine-tuning.
Drivetrain changes the order: FF cars rotate on entry with the rear, RWD exit oversteer starts with Acceleration Sensitivity, and 4WD has the torque split.
One change, one step, three laps. After three changes with no progress, go back to the baseline.

Check yourself

Answer in your head, then open each question to check.

Your FF hatchback won't turn in on corner entry. You've checked you're not braking too late. What do you change first?Open to see the answer

Stiffen the Anti-Roll Bar Rear by 1, or lower the Damping Ratio (Expansion) Rear by 3–5. On FF the front diff can't help the car turn, and an FF baseline already runs little Braking Sensitivity, so you rotate the car with the rear. The front keeps its grip, and the tail helps steer the car in.

Your FR car steps out as you squeeze the throttle out of a hairpin, and you're already unwinding the wheel. What's fix 1?Open to see the answer

Lower Acceleration Sensitivity by 5. On rear drive, heavy lock under power drives both rear tires to the limit together and accentuates oversteer. If that's not enough, soften the Anti-Roll Bar Rear by 1 next.

Your Gr.3 car scrapes through a fast compression at top speed every lap. Why does the Doctor put ride height ahead of the dampers here?Open to see the answer

Downforce is a steady load that pushes the car down for as long as you're fast. Dampers only resist movement while it's happening, so they can't hold the car up. Raise Body Height Adjustment by 3–5 mm at the end that scrapes, then stiffen Natural Frequency there by 0.1–0.2 Hz if it still hits.

You've made three changes for mid-corner understeer and none of them helped. What now?Open to see the answer

Stop and reload the baseline sheet. Then re-diagnose: the push most likely starts on entry, or comes from too much entry speed. Check tires and the baseline before you try again, and start from the phase where the problem first appears.

The inside rear of your MR car spins at the apex of slow corners on part throttle. Do you start with the diff or the springs?Open to see the answer

The diff. Raise Initial Torque by 3–5, or raise Acceleration Sensitivity by 5, so torque reaches the loaded outside wheel. If the bar is much stiffer than the springs, soften the Anti-Roll Bar Rear by 1 afterward to keep the inside rear on the road.