A STRUT BAR, STRUT BRACE, or STRUT TOWER BRACE is mostly an aftermarket addition designed to provide extra stiffness between the strut towers. It is designed to reduce strut tower flex by tying two parallel strut towers together which results in improved chassis rigidity. This results in improved steering precision under high load conditions (e.g. cornering and braking) while reducing understeer, tire wear and metal fatigue in the strut tower area. Furthermore, it also transmits the load of each strut tower during cornering via tension and compression of the strut bar which distributes the load evenly between both towers and reduces chassis flex.

If you’re serious about your car’s handling & performance, you will first be looking at lowering the suspension. In most cases this will be more than adequate. However, if you are a keen driver, you will be able to get far better handling out of your car by fitting a couple of other accessories to it. The first thing you should look at is a strut brace. When you corner, the whole car’s chassis is twisting slightly. In the front (and perhaps at the back, but not so often) the suspension pillars will be moving relative to each other because there’s no direct physical link between them. They are connected via the car body, which can flex depending on its stiffness. A strut brace bolts across the top of the engine to the tops of the two suspension posts and makes that direct physical contact. The result is that the whole front suspension setup becomes a lot more rigid and there will be virtually no movement relative to each side. In effect, you’re adding the fourth side to the open box created by the subframe and the two suspension pillars.

The chassis of the car is the part which experiences the most of the abuse from the driver. It is particularly due to the weight transfer of the vehicle body during fast cornering, hard braking or hard acceleration. In some instances, the weight transfer during cornering may cause one side of the vehicle to experience as much as 3 times more force than the other side of the vehicle, causing enormous chassis flex/ vehicle body deformity and twist, consequently causing tires to lose grip. Deformity and twisting of the vehicle chassis during cornering may cause negative handling traits such as understeering and oversteering.

CHASSIS FLEX is a bad thing for several reasons. The first reason is that we can't control it. You want cornering forces and energy to be handled by your suspension because the suspension has hopefully been setup to handle it in a very specific way in order to make the car handle well. If the chassis is flexing, we have no control over it's spring rate and it definitely is not getting any sort of damping force. Chassis Flex is uncontrolled motion and controlling motion is whole point of suspension tuning. Another drawback of Chassis Flex is that it throws off the alignment. Ruined alignment will throw off force transfers and tire contact patches. Also mitigating the amount of flex in the uni-body will reduce metal fatigue that leads to failures such as cracking and distortion.

Although some cars spend most of their lives driving in a straight line. Such cars might experience the strut towers moving together over time. Track cars spend a lot of their time cornering at over 1G. Thus a track car might see it's strut towers spread apart over the years. What this means is that a strut tower bar can be under tension OR compression depending on the environment that the car is operated in.

The installation of strut bars / Anti-Roll Bars are also essential when attempting to correct oversteering and/or understeering characteristics. As most modern cars go, car manufacturers employ the FF (Front engine, Front wheel drive) setup for improving driver and passenger safety. The natural behaviour of an FF car is to have a slight understeer, due to its heavier front end. Understeer happens when the front wheels lose their traction and won't turn any sharper, even when the steering is being corrected to turn the car more. This will cause the car to go wide instead of following the line. Understeer can be corrected by stiffening the rear end of the vehicle by adding a rear strut brace and a Rear Anti-Roll Bar.

On the otherhand, Oversteer is when the rear tire lose grip and causing the rear end of the vehicle to slide out of a corner. This phenomenon happens particularly to FR (Front engine, Rear wheel drive) or RR (Rear engine, Rear wheel drive) cars with heavier rear ends. Vehicles with In-Car Entertainment Systems that carry a heavier rear load due to the ICE setup will highly benefit from this chassis reinforcement technique. Oversteer can be corrected by stiffening the front end of the vehicle by adding Front Strut Bars and Front Anti-Roll Bars.

A strut bar can give your car a totally different feel. With a strut bar, cornering is easier and the handling is more predictable. You have more peace of mind with the addition of a strut brace because it can also be regarded as a safety upgrade, as it allows for the forces to be evenly distributed during a collision which could reduce the extent of Injuries. Moreover, since a strut bar is designed to tighten up your chassis, the chassis is less likely for it to get damaged or bent. Therefore, your vehicle can last longer. Most economy cars do not come with a strut bar. The reason for this is because manufacturers cannot justify the extra cost when competing in the budget or entry-level market. If you love a vehicle that handles well, a strut bar is a simple way to increase the rigidity and improve the handling of your car.

click here to learn more about Oversteer / Understeer and how to correct it >

What is Body Roll?

Body roll (or lean) happens when you turn into a corner. As your car begins to turn, its weight is thrown to the outside of the corner, causing your car to roll in that direction. Put simply, as you turn left you are thrown to the right and turning right throws you left. Your wheels are in constant contact with the ground so always stay on the same level but your car’s body (and, by extension, the cabin in which you’re sitting) sit on top of springs attached (indirectly) to your wheels – allowing the car’s body to lean independently of the wheels.

Installation of a strut bar and lower arm bar.

Part of the shock of impact transfer to the chassis, causing wheel house

and lower arm deformation.

Equipped with the Ultra Racing’s strut bar and lower arm bar, The shock of impact will be distributed evenly on both sides

What happens during cornering?

The weight transfer and force is more noticable on one side, resulting in unstable handling and increased body roll.

The forces will be evenly distributed by Ultra Racing’s strut bar and lower arm bar, stabilizing the car and improving handling characteristics.

Advantages of installing Fender braces

Fender Braces despite being the least popular in South Africa, are one of the most effective braces to fit to a Vehicle.

The joint between the A-pillar and front chassis will distort due to the shock of impact, causing chassis flex & metal fatigue over an extended time period

Ultra Racing Fender braces will evenly distribute forces and strengthen the section, preventing further damage and offer stable handling. Highly recommend for lowered vehicles or vehicles with coilovers.

Side lower braces

When travelling on uneven / bumpy road surfaces, the center section of the chassis will experience different levels of chassis flex caused by the weight transfer between front and rear.

Ultra Racing side lower bars support the undercarriage and stabilize the weight transfer between front and rear. It can also minimize the damage from side impact.

Anti-Roll Bars / Sway Bars

A sway (or actually anti-sway) bar tends to keep the car from swaying (or more precisely, from leaning to one side or the other). That is what a sway bar does: prevent body lean. A sway bar does nothing at all unless the vehicle is inclined to lean to one side, but when it does start to lean (which usually means the vehicle is turning — every vehicle tends to lean to the outside of a turn), the sway bar applies force to the suspension on each side, upward on one side and downward on the other, that tends to resist the leaning. Every sway bar is a torsion spring — a piece of metal that resists twisting force. The sway bar is attached at each end, one end to one wheel and at the other end to the opposite wheel (both fronts or both rears) so that in order for the wheel on one side to be higher than that on the other the bar has to twist. The sway bar resists that twist, tending to restore the wheels to the same height, and the vehicle to level. That’s why a sway bar does nothing unless the body of a vehicle leans to one side: if both wheels rise (as they would when the vehicle hits a bump) or fall (as at a dip) at the same time, the sway bar doesn’t have to twist, so it has no effect.

When turning into a corner, weight transfer will make the car sway to one side, causing body roll and reducing the steering response and negatively impacting the vehicles stability during cornering.