Anti Roll Bars & Anti Roll Bar Kits with Fitting Position Rear Axle

An anti roll bar is a steel bar running across the car, connected to the suspension at each end and mounted to the chassis in the middle. When one wheel rises relative to the other, the bar twists, and the resistance it generates transfers load across to the other side. That is what stops the body leaning over in a corner.

You will also see it called a swaybar, an anti roll bar, an anti sway bar or a stabiliser bar. Same part, same job, different catalogue.

What is an anti roll bar doing in practical terms? It is the single component deciding how much your car leans when you turn, and on most vehicles it is the cheapest handling change available.

What Does an Anti Roll Bar Do, and What Does It Not Do

The easiest way to understand what an anti roll bar does on a car is to picture what happens without one.

Turn in and weight transfers to the outside wheels, compressing that side and letting the inside extend. The body rolls, the inside tyre unloads and stops contributing much grip, and the outside tyre ends up carrying nearly everything on that axle while sitting at a worse camber angle than it should.

An anti roll bar limits how far that goes. Because it connects both sides, the outside wheel compressing forces the bar to twist, and the bar pushes back, resisting the roll and pulling some load back onto the inside tyre. You get a flatter car, tyres closer to their intended angle, and a response to the wheel that arrives immediately rather than after a lean.

What it does not do is affect ride quality over bumps that hit both wheels at once. Go over a speed hump squarely and the bar barely notices, because both ends move the same amount and there is nothing to twist. That is the whole reason the part exists. You get the cornering improvement without the harshness a stiffer spring would bring.

Not the Same as a Caravan Sway Bar

Worth clearing up early, because the terms collide.

Caravan sway bars and anti sway bars for towing are a completely different product. They control a trailer moving around behind the vehicle and they attach to the towing setup rather than the suspension.

What is on this page is suspension anti roll bars, sometimes listed as anti roll bar parts, which bolt to the car itself and control how much the body rolls in a corner. If you are towing and chasing stability, a rear suspension anti roll bar genuinely helps, but it is not a substitute for proper weight distribution and trailer sway control.

Stiffen the Front to Push, Stiffen the Rear to Rotate

This is where most people upgrading an anti roll bar are actually headed, because the bar is a tuning tool as much as a component.

A stiffer front anti roll bar resists front roll more, which loads the outside front tyre harder and moves the car toward understeer, where the nose pushes wide. A stiffer rear anti roll bar does the same at the back, which frees up the front and moves the car toward oversteer, where the rear rotates more readily.

That gives you a dial. Most road cars leave the factory tuned toward understeer because it is safer and more predictable for the average driver, which is why fitting or upgrading a rear anti roll bar is the most common handling change people make. It neutralises a nose heavy chassis without touching springs or dampers.

Pick-ups, wagons and 4WDs respond particularly well to a rear bar, since they usually have very little rear roll resistance from the factory and gain real stability under load or while towing.

Adjustable Bars and Why the Settings Matter

An adjustable bar has multiple mounting holes at each end, and moving the link between them changes the leverage acting on the bar rather than the bar itself.

Shifting the link inboard shortens the effective lever and stiffens the bar, moving it outboard softens it, and across the positions a well designed adjustable bar covers a substantial spread of rate. That turns one part into a range, so you can set it softer for daily driving and firmer for a track day, or dial in front to rear balance on a car that pushes or rotates more than you would like.

The catch is that adjustment only works if the rest of the system is tight. A flexing link or a soft mount bush blurs the differences between settings until you cannot tell them apart, which is why links and bushes matter more on an adjustable bar than on a fixed one.

Solid or Hollow

Both do the same job and the difference is weight.

A solid bar is simpler and cheaper to produce. A hollow bar achieves a similar rate at considerably lower weight, because the material near the centre of a bar contributes very little to torsional stiffness and is mostly along for the ride.

That matters more than it sounds when the bar sits ahead of the front axle, since weight out there affects how the car changes direction. On a track focused build it is worth paying attention to. On a road car it is a bonus rather than the reason to buy.

The Bar Is Only as Good as What Holds It

An anti roll bar resists roll because the middle stays put while both ends are pushed in opposite directions. Every part of that arrangement has to be rigid.

Anti roll bar bushes at the centre hold the bar to the chassis, and once they soften the bar moves inside them rather than rotating cleanly. Anti roll bar links carry the load from the suspension to the ends of the bar, and any play there is load the bar never receives. Brackets, mounts and lateral locks keep everything where it belongs.

Bars themselves almost never fail, since they are shaped spring steel doing what spring steel does. It is the parts holding them that wear, which is why a bar that felt transformative when it went on and feels ordinary three years later has almost certainly not gone soft.

If you are fitting a new bar, look at the links and bushes at the same time. A new bar working through tired ones will not deliver what it is capable of.

Clamping, Preload and Getting It Square

Anti roll bar work is among the more approachable jobs on the car, since the bar unbolts at four points and nothing needs pressing.

Expect corrosion at the bracket bolts and the link nuts, because both live in poor positions for it and are usually the hardest part of the job.

Clamp the mount brackets down properly. The bar has to rotate inside the bush rather than the bush turning inside the bracket, which means torquing to specification rather than easing off out of concern for crushing the polyurethane. An under clamped bush spins and destroys itself quickly.

Set link length with the car on all four wheels at ride height, not hanging at full droop, and never force a link into position to make it reach. A preloaded bar is already part way through its travel before the car has moved and works unevenly side to side.

Fit both sides before final torquing so the bar sits square, grease the bush bores with a silicone or PTFE based lubricant rather than a lithium or petroleum based one, and check clearance through the full range of suspension travel. No wheel alignment is required afterwards.

Find Anti Roll Bars for Your Vehicle

Round out the install with anti roll bar brackets, anti roll bar relocation kits for lowered or lifted cars and anti roll bar service kits. More handling upgrades sit across our suspension parts range.

Select your vehicle to see the front anti roll bars, rear anti roll bars, complete kits, links, bushes and mounting hardware available for it, and check each listing for the diameter and whether the bar is fixed or adjustable. Every Whiteline component is backed by our warranty, a fitment guarantee and 30 day returns.