What’s wrong with rubber?
Rubber has traditionally been used for automotive suspension bushes. It has the advantages of low cost, is easy to work with, it can be used for a wide variety of applications and is able to provide a level of insulation between steel components. However, it has some significant disadvantages:
•Rubber is vulnerable to abrasion
•Rubber will deteriorate when exposed to ultra-violet light and water
•Rubber will deteriorate when exposed to chemicals such as oil, petrol, salt, antifreeze, and other solvents and airborne contaminants.
All this causes the rubber to start to lose its elasticity and as importantly its resilience. In time rubber will lose the shape it was designed to be. The car’s suspension components start to move to a position different from the ideal, with a loss of handling precision and predictability and accelerated wear of other components and tyres.
In contrast, polyurethanes, especially those manufactured using cold pour/thermo setting processes, can be resistant to all of these problems and retain its original shape. The result is a suspension bush which will last a lot longer than rubber – and will perform consistently throughout its life.
But doesn’t polyurethane have excessive NVH?
(Noise Vibration & Hardness)
Traditionally polyurethane has been associated with being a hard material, giving excessive NVH. But with Superpro due to the unique properties of the raw material and the design techniques used in the manufacture of Superpro Polyurethane Bushes, they will not cause any extra NVH over the standard rubber bushes. This makes them suitable for road cars and race cars alike.
In addition Superpro doesn’t generally offer different hardness’s for their location kits with colour coded bushes. The reason for this being that Superpro believes that it is important to supply a bush that is designed to achieve the optimum performance for its location on the car – without creating a harsh or uncomfortable ride. This means that a car may need bushes of three or four different materials to deliver the best improvement in suspension performance without creating excessive levels of NVH. Colour coding by material hardness would result in either specifying multi-coloured car kits of varying hardness of materials, or kits of one colour and hardness which would compromise performance.
Superpro bushes, while being direct replacements, are not identical to OEM. Superpro has a complete understanding of the material being used, which requires that each bush is specifically engineered due to the nature of polyurethane. This can give Superpro bushes a major advantage over the standard rubber versions as they can eliminate problems where the rubber bushes are prone to premature failure.
Why should I use Superpro when it’s so expensive, or is it?
While the cost of buying Superpro may be significantly more than an OEM rubber bush, we believe that you are investing in a product that will save you money in the long run. Superpro bushes have a long service life and their performance doesn’t degrade over time. This means that you don’t have to replace bushes as often, saving you money and time.
Secondly, while material and manufacturing costs for polyurethane are high – the cost of new product development is relatively low. With the enthusiast markets preference for ‘whole car’ solutions this means that the Superpro catalogue includes many applications which are only available from the OEM or in the aftermarket as a part of a complete arm – or are simply not available. All of a sudden – what was an expensive product now looks very cost effective – often as much as 50-60% cheaper.
Also, polyurethane can be used to ‘fix’ a weak original design where rubber is simply not man enough for the job. This can help reduce wear of other components and the need for embarrassing explanations about why the bush that was replaced last year has failed the mot again this year!