I fitted these bushes to my MX5 about 4 months ago. Made a big difference, car is more responsive to steering input, soaks up vibration and harshness better and doesn't crash into potholes anymore. The steering wheel also deflects much less when a wheel hits a pothole. FYI my '92 had 68k miles on it at the time and my OE bushes were definitely shot, the car was becoming very crashy and unpleasant to drive over anything but smooth road surfaces, so it must be born in mind that I am comparing shot OE bushes to the PowerFlex ones. The PowerFlex bushes have improved the car enormously, it not only feels much more responsive, it also feels like new again and the suspension doesn't seem any harder. Replacing old bushes *really* is worth doing when your car gets past 60k miles, but only if you intend to keep the car a long time as it is expensive (about 350 to 400 for the bushes alone and, if you don't do it yourself, Mazda and most other garages for that matter will charge 8 hours+ labour on top). It's not a difficult job BTW, but it does take time and elbow grease, there are 22 bushes in all to be pressed out and the wishbones obviously have to be removed (front ball joints don't have to be separated, but it's easier if you do).

I'm very pleased with bushes and you can probably find more detailed comments by me in the PowerList archives. (1/01)

Interesting that??

In an engineering sense elastomeric components don't wear or suffer fatigue type damage. A Durometer reading and torque tensions today should be almost identical to the day the component was manufactured, if:
. there is no perishing,
. bond separation, or
. splitting in the rubber of the component.

That is one of the reasons bonded elastomeric components are used in helicopter main rotor heads.

Though there are many stories about the plastic replacements, and I have used them in my past four wheel drives, I have found that that the non rubber polymer bushes are not as forgiving.

The non rubber polymer bushes are cheaper than the rubber components; yet the actual car makers don't use them. Something to think about??? (1/01)

One thing is for sure here, and that is that after 8 years exposed to the elements there will be perishing of the exposed rubber components. The rubber bushes I took off certainly had visible surface perishing. A poor comparison I know, but a rubber band will be of little use after a year or so left exposed to air, it will have cracked and also permanently stretched if in use at the time. If the rubber is sealed from the environment and is not stretched beyond its elastic limit (i.e. doesn't enter the plastic phase), then you are quite right it should last forever, but I doubt either of those rules applies to a car suspension bush. As to the reality of whether or not bushes wear all I can say is that the car was very much better in all departments after replacing the bushes. Steering response improved, V&H was down and the general shuddering and crashing over potholes was much better damped. There are certain bits of road where the car always crashed and shuddered, to the point where I would take a particular line to reduce it. Now all I get now is nice quiet thud noise and little shuddering. Steering feel has not suffered. I am certainly not alone in noticing my MX5 becoming 'looser' and more crashy with age and a subsequent improvement after fitting new bushes. My car feels like new again, no doubt because road harshness is being insulated from the cabin better by the new bushes. All this may be true of simply fitting new bushes to any older MX5, OE or polyurethane ones, but I can only comment on the improvements the polyurethane ones made over old worn bushes on my car.

PowerFlex claim the complete opposite of the cost factor, they quote the production cost of a Polyurethane bush to be 10x that of a similar rubber component. But then they would;-)

Have a look at the FAQs on their website it's at http://www.powerflex.co.uk/ (1/01)