Lesson 4: Anti-roll bars

The quickest balance knob in the garage. Learn what a stiffer or softer bar does at each end of the car, why the stiffer end slides first, how the bars share the work with your springs, and why GT7's own tuning guide saves them for the final tweak.

About 12 minutes
Requires Fully Customizable Suspension
Settings: Anti-Roll Bar, Natural Frequency

What the bar actually does

An anti-roll bar is a torsion spring: a steel bar that runs across the car and links the left and right wheels on one axle. Each car has two, one at the front and one at the rear, and GT7 lets you set them separately.

Here's the key idea. When both wheels on an axle move up together, say over a crest or a bump that spans the whole track, both ends of the bar move the same amount. The bar just rotates in its mounts. It doesn't twist, so it does nothing. That job belongs to the springs (Natural Frequency, Lesson 2) and the dampers (Lesson 3).

In a corner, the body leans toward the outside. The outside wheel compresses, the inside wheel extends, and the bar gets twisted. It fights back by pushing the body up over the outside wheel and pulling the inside wheel's side down. The car rolls less. So an anti-roll bar is a spring that only exists in corners, and anywhere else the two sides move differently: a curb under one wheel is the classic example.

Rear view of the rear axle. The bar (amber, because it's the rear) only twists when the two wheels move by different amounts. In the left-hand corner the body leans to the right, toward the outside of the turn, and the twisted bar resists that lean.

Why the stiffer end slides first

In every corner, load moves from the inside tires to the outside tires. How much load moves in total depends on the car's weight, its center-of-gravity height, its width and how hard you're cornering. The anti-roll bars barely change that total. What they change is which axle carries more of it.

The stiffer end of the car resists roll harder, so it takes a bigger share of the load transfer. Its outside tire ends up heavily loaded and its inside tire goes light. That sounds fine until you remember the rule from Lesson 1: tire grip grows with load, but less than in proportion. Two tires sharing the load evenly grip more than one tire doing most of the work. So the more unevenly loaded axle has less total grip, and that end reaches the limit first.

Stiffer at the front: the front tires give up first, and you get understeer.
Stiffer at the rear: the rear tires give up first, and you get oversteer.

This is exactly what GT7's own manual says: a stiffer front bar makes the car "easier to understeer", and a stiffer rear bar makes it "easier to oversteer".

Same corner, same total load transfer, different split. The thick line marks the stiffer bar. Its axle has one heavily loaded outside tire and one light inside tire, so it has less total grip and lets go first. Front loads are blue, rear loads amber.

Front axle
Rear axle

Notice the trade. Stiffening one bar doesn't just hurt that end; it also helps the other end, because it takes load transfer away from it. That's why bars are such a quick balance knob: one click moves the limit from one axle toward the other.

Front bar and rear bar, phase by phase

Bars work hardest once the car has taken its set in a corner, so their biggest effect is Mid-corner. But they color turn-in and exit too.

Front bar

Stiffen Anti-Roll Bar Front and the nose takes its set faster. Turn-in feels sharper and the steering more direct, because the front isn't busy leaning first. Then, as you hold the steering through the middle of the corner, the overloaded outside front tire runs out and the nose starts to push wide: mid-corner understeer.

Soften it and turn-in gets a little lazier, with more lean before the car responds. In exchange, the two front tires share the load more evenly, so the nose holds the line through the apex. On a car that pushes in long corners, a softer front bar is often the single most effective click.

Rear bar

Stiffen Anti-Roll Bar Rear and the car rotates more around the apex: the rear lets go a little earlier and helps point the nose, which reads as more oversteer. The price comes on exit. The stiffer rear bar lifts load off the inside rear tire, so on a rear-drive car that tire spins up as you add throttle. With an open diff you lose drive; with a locked diff the whole rear can step out in a snap.

Soften it and the inside rear keeps more load. You feel a calmer, more planted rear and better traction on exit, at the cost of some rotation, so the car may push a little more mid-corner.

By drivetrain

FF. The rear wheels don't drive, so exit traction at the rear isn't your problem. A stiffer rear bar is a classic way to help a front-driver rotate, and it's common for FF cars to run the rear bar at or above the front.
FR, MR and RR. Exit traction comes from the rear tires, so keep the rear bar on the softer side. Powerful MR and RR cars, which already carry weight at the back, often want it softer still.
4WD. Start in the middle of the range. If the car pushes mid-corner, one step stiffer at the rear is a reasonable first try; for push on power, look at the diff and torque split first (Lessons 6 and 7).

Rule of thumb

The stiffer end slides first. For mid-corner push, soften the Front bar or stiffen the Rear bar. For a loose mid-corner, do the opposite. Pick the end that doesn't hurt you elsewhere: on rear-drive cars, softening the front protects exit traction; on FF, stiffening the rear costs almost nothing.

Bars and springs share the job

Your springs resist roll too. The total roll stiffness at each end is springs plus bar. The difference is that springs also handle pitch under braking and acceleration, and every bump that hits both wheels. Bars only handle roll.

That gives you two ways to reach the same amount of roll control. GT7's tuning guide, in the official Beyond the Apex magazine, puts it plainly for high-speed tracks: stiffer springs pair with slightly softer bars, and softer springs pair with stiffer bars. Soft springs with firmer bars ride bumps well and still corner flat. Stiff springs with softer bars give a firm platform while keeping the left and right sides somewhat independent over curbs.

Pick one stiff partner, not two. The first two setups reach the same total roll stiffness by different routes. Stacking stiff springs on stiff bars overshoots: the car corners flat but skips over curbs and lifts its inside wheels.

The same guide warns about going too far: when the bars get too stiff relative to the springs, the inside wheel unloads or even lifts off the road. A lifted wheel has zero grip, and on a driven axle it spins freely. That's also why the guide calls anti-roll bars "best treated as a final tuning tool": set the springs and dampers first, then use the bars to fine-tune the balance.

There's a second reason bars are the natural balance knob in GT7. The tuning guide recommends running Natural Frequency the same front and rear in most cases. If your springs are matched, the difference between the Front and Rear bars is what sets the roll balance between the two ends.

One practical consequence: if you raise Natural Frequency for racing tires or downforce, the springs now carry more of the roll job. Keep the bars where they were or soften them a step, rather than stiffening everything at once.

Common mistake

Maxing both bars "for less roll". The car feels sharp for a lap, then skates over curbs and gets nervous over bumps, because a curb under one wheel is exactly the one-sided movement a bar transfers across the car. It also hides the real balance problem instead of fixing it. Set the springs first; the bars come last, one step at a time.

Balance and roll explorer

Anti-Roll Bar Front: 5

Anti-Roll Bar Rear: 5

Springs (Natural Frequency)

Drivetrain

Illustrative, not a simulation. The lean is exaggerated so you can see it change.

Where to find it and where to start

In GT7

Anti-Roll Bar, set separately for Front and Rear. It's a unitless level; on most cars the slider runs 1 to 10. Higher means stiffer and less roll. Natural Frequency (Hz) sits on the same screen. Before a race you can also reach both through Quick Menu > Settings > Car Settings > Detailed Settings, where race regulations may lock some options.

Requires Fully Customizable Suspension from the Tuning Shop. Race cars such as Gr.3 and Gr.4 usually have it fitted already.

Anti-Roll Bar at a glance
Setting	Unit	Range on most cars	Stiffer (raise) does	Softer (lower) does
Anti-Roll Bar Front	level	1–10	Sharper turn-in, then more understeer mid-corner	Lazier turn-in, more front grip mid-corner
Anti-Roll Bar Rear	level	1–10	More rotation, more oversteer; weaker exit traction on rear-drive cars	Calmer rear and better exit traction, a little more push

The table below gives the course's starting points by class. These are coaching numbers, not values from the game: a sensible first try that you then adjust by feel. The reasoning is simple. Grippier tires and stiffer springs mean bigger cornering loads, so race cars sit a step or two higher. The front usually starts a step above the rear, because a slightly stable, mildly understeering car is the safe place to begin tuning from.

A sensible first try, by class (course starting points, not game values)
Car	Front bar	Rear bar	Why
Road car / N, comfort or sports tires	4–5	3–5	Soft springs roll a lot; moderate bars control it without lifting a wheel.
Road car on racing tires	5–6	4–6	More grip means more roll to control.
Gr.4	5–7	4–6	Stiffer springs and smooth tracks; bars fine-tune the balance.
Gr.3	5–7	4–6	Same idea; downforce and stiff springs carry much of the load.
Any class in the wet	1–2 softer	2–3 softer	Less grip, so let the tires share load; the rear especially.

Then adjust for the drivetrain. On FF, a sensible first try is one or two steps stiffer at the Rear than the table says. On powerful FR, MR and RR cars, start the Rear at the low end of its range.

In the wet, GT7's tuning guide says to soften the springs, damping and anti-roll bars, the rear bar possibly by a lot. With little grip, an unevenly loaded rear axle lets go suddenly, and a soft rear bar is your best insurance against a snap on exit.

Note

Every car has its own slider ranges. If a number here doesn't fit your car, place it at the same spot within your car's range. Suspension changes can also move your PP, so check it before a PP-limited event; if it shows "!", press Triangle in Car Settings to recalculate.

Symptom to fix

Use this when you can name the phase. Bars are strongest in the steady middle of a corner; for problems on the brakes or the first moment of turn-in, dampers and the diff usually come first.

Symptom	Phase	Try, in this order	Why it works
Nose pushes wide as you hold steering	Mid-corner	Soften Anti-Roll Bar Front by 1 Stiffen Anti-Roll Bar Rear by 1 (try this first on FF)	Shares front load across both front tires, or moves load transfer to the rear.
Rear feels loose, car over-rotates	Mid-corner	Soften Anti-Roll Bar Rear by 1 Stiffen Anti-Roll Bar Front by 1	Evens out the rear tire loads, so the rear axle grips more.
Inside rear spins up, or rear snaps out on throttle (rear-drive)	Exit	Soften Anti-Roll Bar Rear by 1 Then check the LSD's Acceleration Sensitivity (Lesson 6)	The inside rear keeps more load, so it can put power down.
FF car pushes from the apex out, before you're on full power	Exit	Stiffen Anti-Roll Bar Rear by 1 If the push only starts as you add throttle, go to the LSD first: a step more Acceleration Sensitivity (Lesson 6)	Helps the car rotate; the undriven rear has no traction to lose. Power-on push is a diff job.
Turn-in feels slow and vague, the car leans before it responds	Entry	Stiffen Anti-Roll Bar Front by 1, then watch for mid-corner push	Less front roll means the nose takes its set sooner.
Hops over curbs, inside wheel goes light or lifts	Mid-corner	Soften the bar at the end that hops by 1–2 Check that Natural Frequency isn't also high	Bars too stiff for the springs unload the inside wheel and pass one-sided hits across the car.
Slides at both ends in the wet	All phases	Soften Anti-Roll Bar Rear by 2–3 Soften Anti-Roll Bar Front by 1–2	On low grip, even tire loads matter more than a flat body.

Try it on track

An FR road car on sports tires with Fully Customizable Suspension. Pick a track with one long, steady-throttle corner, ideally a sweeper where you hold the same steering angle for a couple of seconds, and use it as your test corner every lap.

Run three clean laps on your current settings. In the test corner, note how much the nose drifts wide while you hold steering.
Soften Anti-Roll Bar Front by one step. Change nothing else.
Run three more laps, at the same speed and line, and focus only on the middle of the test corner.

What you should feel: a touch more lean and a slightly lazier first moment of turn-in, then the nose holds its line instead of running wide, so you need less steering mid-corner. Exit should feel no different. If you can't feel anything, go one more step and compare again.

Key takeaways

A bar only works when the left and right wheels move differently: in corners and over one-sided curbs, not over symmetric bumps.
The stiffer end takes more load transfer and slides first. Stiffer front: more understeer. Stiffer rear: more oversteer.
A stiffer front bar sharpens turn-in but pushes mid-corner; a stiffer rear bar rotates the car but costs exit traction on rear-drive cars.
Springs and bars share the roll job. Pair stiff springs with softer bars, or soft springs with stiffer bars, never both stiff.
Treat the bars as the final tweak after Natural Frequency and dampers, change one step at a time, and go softer in the wet, the rear especially.

Check yourself

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

Your FR car understeers through the middle of long corners but puts its power down cleanly on exit. Which single bar change do you try first?Open to see the answer

Soften the Anti-Roll Bar Front by one step. It adds front grip mid-corner without touching the rear. Stiffening the rear bar would also reduce the push, but it would take load off the inside rear and risk the clean exits you already have.

Your FF hatchback pushes wide from mid-corner to exit. Which bar do you change, and which way?Open to see the answer

Stiffen the Anti-Roll Bar Rear by one step. The rear takes a bigger share of the load transfer, so it lets go a little earlier and helps the car rotate. On FF the rear wheels don't drive, so you lose no exit traction. If it still pushes on power, look at the LSD next.

Your MR car spins its inside rear wheel out of slow corners and sometimes snaps sideways. What do you change on the bars?Open to see the answer

Soften the Anti-Roll Bar Rear by one step. The inside rear tire keeps more load, so it can transmit drive instead of spinning. The car will rotate a little less mid-corner; that's the trade.

Your Gr.4 setup is dialed for the dry, and the next race is wet. What happens to the bars?Open to see the answer

Soften both, the rear more. A sensible first try is one or two steps off the front and two or three off the rear, alongside softer springs and dampers. GT7's tuning guide says the rear bar may need to come down by a lot, because on low grip an unevenly loaded rear lets go suddenly.

You raised Natural Frequency at both ends for racing tires, and now the car hops over curbs with the inside wheel going light. What's the likely cause?Open to see the answer

Stiff springs stacked on stiff bars. The springs now carry more of the roll job, so the bars are too stiff for this setup. Soften the bar at the end that hops by a step or two. Stiff springs pair with softer bars.