10 MIN TECH
We quiz Hardrace all about adjustable suspension arms.
WHAT ARE UPRATED ALIGNMENT ARMS AND WHAT DO THEY DO?
Uprated alignment arms can offer various benefits. They are stronger than original equipment, are usually adjustable for length and usually feature either uprated bushes or spherical bearings.
Adjustable length allows you to set alignment. It means you can dial out excessive negative camber introduced when lowering a vehicle, add negative camber to improve mid-corner grip, add castor to increase negative camber gain when cornering, or add or reduce toe to increase agility or stability, depending on what you want from the car.
The rubber bushes used in the original arms are designed to minimise transmission of noise and vibration to the cabin. They are therefore relatively soft, allowing deflection of the arm when the arm is placed under load. This deflection allows the wheel to move and the car’s suspension geometry to alter as loads on the various arms alter. This can lead to the car feeling imprecise when driven hard. The movement in the bush only gets worse as the car ages and the bushes soften and wear.
Uprated arms are offered with an option of a hardened rubber bush to minimise deflection while retaining a high degree of noise and vibration isolation, or spherical bearings to eliminate deflection completely.
ARE THEY ALL THE SAME?
No. Some adjustable alignment arms offer a spherical bearing only, with no option for the highly durable and more road car-friendly rubber option that Hardrace makes available. Most of the spherical bearings used by Hardrace are a unique design with a moulded rubber seal that totally encompasses the bearing with no chance of water and dirt ingress, meaning the life of the bearing is extended hugely compared to the traditional openstyle bearing.
WHAT ARE THEY MADE OF?
The majority of the Hardrace arms are made from steel, with the bushes made from durable hardened rubber.
HOW DO AFTERMARKET ALIGNMENT ARMS DIFFER FROM OEM VERSIONS?
OEM arms tend to be pressed steel and use rubber bushes designed to isolate the cabin from noise and vibration and are, as a result, soft with excessive deflection when placed under load – leading to geometry changes during hard driving and a car that’s less responsive to steering input. WHY, OR WHEN, WOULD YOU NEED TO UPGRADE YOUR ALIGNMENT ARMS?
As the car gets older, the original rubber bushes get softer and start to perish. The softer the bush gets, the poorer the car’s response to steering input and the more the handling deteriorates. Changing old and worn bushes for fresher, stiffer ones instantly improve the car’s handling. That’s one reason to change. The other reason is when you want to maximise your car’s performance by setting up the geometry. The original arms offer very little in the way of adjustment; generally front toe is the only adjustable part of the car. Front toe is only one part of setting up a car. You also need to be able to set camber, castor and rear toe. Hardrace adjustable arms allow you to do this.
HOW IMPORTANT IS IT TO GET THE RIGHT TYPE OF ALIGNMENT ARM?
Alignment arms attach the wheels to the chassis. It’s vital that the product is fit for purpose and will stand up to the stresses placed upon it, whether on the road or on track. It’s not just the strength of the arm that’s important, but the durability is also a vital consideration. Open rose joints may be fine for race cars that cover few miles and are checked frequently, but they aren’t so suitable for a road car covering tens of thousands of miles.
The best compromises for road cars are adjustable arms with uprated rubber bushes, as they offer the best blend of everything: adjustability, durability and reduced deflection. If you want to eliminate deflection completely then Hardrace’s unique fully-sealed spherical bearings are a great choice for a road car over an open rose-joint type, as they’re completely isolated from the elements.
OTHER THAN ENSURING YOU GET THE RIGHT ONE FOR YOUR APPLICATION, WHAT ARE THE MOST IMPORTANT THINGS TO LOOK OUT FOR WHEN BUYING UPRATED ALIGNMENT ARMS?
There are a number of companies manufacturing alignment arms. Some are good, some are not so good, and some are plain dangerous. Some are designed specifically for high-mileage road usage, and some are designed for motorsport with low usage life and regular inspections.
You also need to ask yourself, ‘What do I know about the company? Is it well established? Do I trust the firm to produce a safe product? Can I get replacement components if I need them?’
Price is an important factor, but products with poor-quality components can be dangerous – the consequence of a rose-joint failure doesn’t bear thinking about.
The arm design is also important – Hardrace have seen designs that allow the joints to work loose and unwind themselves over time. Be warned!
WHAT ARE THE LIMITATIONS OF OEM ALIGNMENT ARMS? DO AFTERMARKET ITEMS SUFFER THE SAME FATE?
OEM arms are designed to be cheap and maximise cabin comfort. There is nothing particularly wrong with them for most drivers, but for the enthusiastic driver, their cheap design with no adjustability and excessive bush movement becomes a limitation.
WHAT OTHER MODS SHOULD YOU CONSIDER WHEN UPRATING YOUR ALIGNMENT ARMS?
Nothing else needs uprating when fitting uprated arms. It tends to be the other way round – when you fit coilovers or lowering springs, it’s advisable to fit adjustable arms so you can correct the negative aspects of the geometry changes caused by lowering the vehicle.
If you’re going to the time and trouble of fitting coilovers then it’s because you want to improve the handling of the car – and it’s not possible to maximise the handling improvement without also optimising the geometry.
ARE THERE ANY DOWNSIDES TO UPRATED ALIGNMENT ARMS?
It’s important that the car’s alignment is set up by someone who knows what they’re doing. Buying a full set of arms, bolting them to your car and then setting them by eye is a fool’s game; you’ll never get optimum performance and can potentially make the car outright dangerous.
If you are going to the time, expense, and trouble to buy and install adjustable arms, then this must be followed through by a proper set-up. You don’t need to spend a fortune on having the car aligned, and you can indeed do it at home using the string method if you are careful and methodical, but you do have to know what to set the various adjustable elements to.
“If you’re going to the time and trouble of fitting coilovers then it’s because you want to improve the handling of the car – and it’s not possible without also optimising the geometry”