Hardrace BMW E8x 1 Series / E9x 3 Series Adjustable Rear Upper Control Arms with Uprated Rubber Bushes

Hardrace BMW E8x 1 Series / E9x 3 Series Adjustable Rear Upper Control Arms with Uprated Rubber Bushes

The first benefit to fitting the Hardrace alignment arms is that they come with either an uprated bush or a rose joint. These uprated components minimise the movement in the arm in comparison to the standard items. You want minimal movement as any movement translates through to the steering in the form of vagueness and a lack of response the steering input. Each and every original bush has a degree of slop built into it to maximise the cars compliancy and minimise noise and vibration being passed into the cabin. This soft nature is exaggerated with age as the bush starts to deteriorate and their resistance to forces reduces leading to greater and greater deflection under load. As you turn the steering wheel the original bushes start to take the strain and in doing so compress. As they compress you have to compensate via the steering wheel as the original inputs effect is reduced via the bushes squashing.

You can improve the cars steering response and reaction to input by minimising or eliminating the play that exists in the original soft bushes. For the majority of road cars the Hardrace uprated rubber bushes will be sufficient. We use rubber rather than polyurethane due to the better noise and vibration absorption properties with no loss of effectiveness in reducing deflection in comparison to polyurethane. If you want to eliminate play completely then we offer rose jointed bushes. These provide a complete elimination in play for maximum response to steering input. Rubber and polyurethane bushes provide significant resistance to arm movement, they want the arm to sit in the position it was fitted in so when the wheel moves upwards through its travel the bush tries to push the arm back down to its resting position. The rose joints allow free movement of the arm with minimal stiction. This allows the suspension to work more efficiently improving the spring and dampers ability to function as designed and keep the cars tyres in contact with the ground and control body movement.

The majority of the Hardrace arms are adjustable. This allows you to alter key elements of the cars geometry to optimise the handling characteristics.

Camber:

When you corner the cars body rolls. As the cars body rolls the outside wheels stand upright and then start to lean outwards. This is called negative camber. Conversely as you lower a car you tend to introduce additional static negative camber. The more you lower the vehicle the more negative camber is introduced. Negative camber is the wheel tipping in at the top.

You want sufficient static (i.e with the car stood at rest) negative camber to prevent positive camber under hard cornering but conversely excessive negative camber introduced when you lower a vehicle will lead to accelerated inside edge tyre wear, reduce traction for straight line acceleration and reduce the cars maximum braking ability. Hardrace adjustable camber arms allow you to set the camber correctly.

Castor:

Castor is the angle of the front strut when seem from the side of the vehicle. Adding castor increases dynamic camber, i.e. adds camber when cornering. This means you can run less static camber as the castor adds more camber when you need it. Having to run less static camber improves traction, reduces tyre wear and improves the cars potential braking abilities through improved grip. Adding castor also improves steering feel by making the steering heavier. This generates additional feedback so giving the driver more communication with what the tyres are doing. More information means you can driver closer to the edge more accurately meaning you can go faster. Hardrace adjustable castor arms allow you to adjust castor.

Toe:

All cars have adjustable front toe built in as standard but most done have any provision for adjusting rear toe. Hardrace adjustable rear toe arms allow you to set the rear toe as required, be it toe in to generate heat more quickly and increase turn in stability or toe out to make the car more nervous and quicker to change direction for drifting or tight circuit work. Note that adjusting camber and castor also effects toe so you need the ability to reset toe if you go for camber adjustable arms.

This Kit Consists of:

2x Hardrace Adjustable Rear Upper Control Arms with Uprated Rubber Bushes

This Kit will fit the following Vehicles:

BMW 1 Series E81 Hatchback
BMW 1 Series E82 Coupe
BMW 1 Series E87 Hatchback
BMW 1 Series E88 Convertible
BMW 3 Series E90 Saloon
BMW 3 Series E91 Touring
BMW 3 Series E92 Coupe
BMW 3 Series E93 Convertible