What do suspension bushes do?
Suspension bushes are fitted to cars at all points where the vehicle chassis is joined to a moving suspension component. They are fitted to provide a noise and vibration absorbing barrier between the road and the driver.
Why are standard bushes made from rubber?
Rubber acts as a sound barrier, damping out noise and vibration. Without them cars would feel much harsher and noisier. Rubber is also very cheap. Polyurethane, as a raw material is about ten times the price of rubber, plus it is more expensive and slower to process. Cars are all about marketing. As long as the standard rubber bushes work without serious failure for two or three years then the manufacturer is happy.
Why fit polyurethane suspension bushes?
Polyurethane bushes (also called PU bushes or Poly bushes) improve road holding and chassis performance by controlling the amount of unwanted flex in the suspension. This means that the suspension is doing what it is supposed to do. It means that the tyres have greater contact with the road at all times therefore improving safety and performance. Correctly formulated polyurethane (as used by Powerflex) is as good if not better at noise, vibration and harshness suppression when compared to rubber.
What polyurethane suspension bushes are available?
Powerflex make replacement polyurethane suspension bushes for anti roll bar mounts, wishbones, track control arms (TCA), engine mounts, rear beam mounts, tie bars, diff mounts and steering rack mounts to name a few.
Why are Powerflex suspension bushes the best?
- Powerflex offer the best fit (unlike other brands)
- Advanced polyurethane material
- Same noise suppression qualities as rubber bushes
- Same vibration absorption properties as rubber bushes
- Precision machined stainless steel inserts (where required)
- Ultra-violet, petrol, oil & acid resistant
- Lasts 10 times longer than rubber bushes
Other manufacturers make suspension bushes from polyurethane, but only Powerflex manufacture them with the correctly formulated grade of polyurethane designed to be as good if not better than rubber at noise, vibration & harshness suppression!
Never underestimate the importance of a good fitting suspension bush. The last thing anyone wants is to find that their cheap bushes won't fit when their car's suspension components are all in pieces. An investment in top quality Powerflex polyurethane suspension bushes will result in a stress free fitting job and a lifetime of performance.
Can polyurethane bushes be used on track cars?
Yes, but amazingly some track & race cars are still using rubber bushes! They would benefit hugely from an upgrade to polyurethane ones such as those made by Powerflex. They will outlast rubber by a factor of ten. They will control the geometry much more accurately during rapid suspension movements and they will reduce tyre wear.
Can polyurethane bushes be used on a road car bushes?
Yes. For exactly the same reason as above. If a cars tyres are in better contact with the road and the suspension movements are being controlled more accurately then tyre wear will be dramatically reduced. It's not unusual for customers to state that they have doubled the life of their tyres after fitting Powerflex bushes. Worn bushes are dangerous and will wear tyres prematurely. Have you ever taken your car into a tyre shop with tyres which are worn out on the inner or outer edges but perfectly legal everywhere else? You assume the tracking is wrong, but when the shop checks, it is correct. This is bush wear. When the car is stationary the tracking is correct but as you move and the loads increase then the tracking goes out. Come to a stop and the tracking is right again.
Our guide on fitting Powerflex poly bushes
Powerflex design all their bushes so that they can be fitted without special tools. However sometimes it is a lot harder to remove the old bushes than it is to fit the new ones. If you feel you have very little mechanical knowledge, experience, talent or tools, either ask a friend or get them professionally fitted. Polyurethane bushes made by Powerflex are designed, in general, to be fitted by hand by a home mechanic with no special tools. However it is not always possible to remove the old bushes without some hand tools. The following tips will help you to remove the old bushes if they are not simply a push out bush.
Tip 1: A blow torch may be necessary to burn the old rubber bush out of the arm.
Using a tube, a socket and a vice it is often easy to remove an old bush like this.
Tip 2: Some bushes have a metal outer sleeve which will always need to be removed. Push or burn out the old rubber, the outer sleeve is then clear to see, then cut the metal outer sleeve along its length with a hacksaw. Cut until the saw blade becomes tight. This means you have cut through the outer sleeve and the tension has clamped the blade.
Tip 3: Bushes with a flange can be chiselled out (especially useful on the Ford Escort Mk 5 & 6).
Tip 4: Some more difficult bushes can be removed by drilling through the outer sleeve.
Measuring Anti Roll Bar Sizes
Sometimes it is necessary to measure the anti roll bar diameter accurately to choose the correct size bush for your car. Here are three different ways of doing this;
Method 1: The best way by far is to measure your anti roll bar diameter with a vernier calliper. Choose a straight part of the anti roll bar and make sure the area is clean before measuring the diameter.
Method 2: If you do not have a vernier calliper you can sometimes measure the anti roll bar with a ruler by eye, but this method can be unreliable.
Method 3: The third way to measure the diameter of your anti roll bar is to wrap a measuring tape around the bar to measure the circumference. Then, divide this measurement by 3.14 to calculate the diameter. (Example: Using the measuring tape method the circumference is measured at 60mm. 60mm divided by 3.14 is 19.10mm. Bush sizes are available in 18mm, 19mm and 20mm. In this case you would choose the 19mm option as it is closest to the 19.10mm measurement calculated)
Measuring Bush Sizes
Sometimes it is necessary to accurately measure the diameter of the original bush so that you can choose the correct size for your car. Here are some tips on doing this;
Tip 1: It is always best to remove the bush from its housing and measure the inside diameter of the housing where the bush once sat, rather than measuring the bush itself. This is because the bush can become deformed whilst being removed.
Tip 2: The best way to measure the bush diameter is with a vernier calliper. Alternatively a ruler can be used.
Tip3: If measuring a bush whilst it is still in place on the vehicle it should be noted that the visible part of the bush may not represent its true diameter.
