PowerFlex -frictionless bushings

[MichaelD]

Anyone used these bushings from Powerflex?

 

Caterham Seven all models

 

We have revisited the full applications for the Caterham range of Sevens including CSR and added some clever new design features. The bushes that we have designed for this unique vehicle are, in themselves, unique.

 

This car is one of the lightest and finest handling cars on the planet, with many owners spending thousands on spring/damper units trying to achieve perfect handling.

 

However we have always been concerned that whilst the dampers themselves feature 21st century technology the bushes are from a different era. The design of the factory bushes are an inner and outer steel tube with bonded rubber acting as the isolator. The problems that arise from this design are two-fold. The rubber bond breaks allowing the centre of the bush to float fore and aft, however if the bush is in good condition it acts like a spring. Multiply that spring effect by four on each corner and the fact that the spring rate changes as the bush gets older means that the damper does not have total control of the suspension.

 

Of course a spherical joint is the precision answer but not acceptable for the road.

This is why Powerflex have developed the frictionless bush range for this car. With the precision of a spherical and the performance of polyurethane. The bushes feature a frictionless PTFE lined bearing and polyurethane outer which doubles as a weather seal and vibration damper.

All bearing parts are manufactured in stainless steel/PTFE and like all of our products carry a life time warranty.

Details of these new parts and full application lists for all of the different suspension configurations can be found here:

http://www.powerflex.co.uk/products/Caterham-4/t1.html

[Alaskossie]

I originally was going to upgrade my new Caterham S III with Powerflex bushings in the rear suspension and diff area as I assembled it. But some discussions with engineering types, including Seven owner BobS, persuaded me not to.

 

Even though the steel-centered rubber bushes supplied by Caterham may not be ideal for the purpose (at least in terms of longevity), the thinking is that there is a certain aopunt of compliance that is anticipated and built into the Caterham assemblies.

 

if this is lost through the substitution of entirely non-compliant poly bushes, then things may not work together as intended,and the additional stresses introduced by loss of compliance may stress or break things.

 

Any thoughts or comments?

[JohnK]

Anyone used these bushings from Powerflex?

...

Caterham Seven all models

...

We have revisited ...

 

Of course a spherical joint is the precision answer but not acceptable for the road.

 

...

 

 

Before I order my Koni's, anyone care to comment on why this is so?

[danilo]

I've used sphericals in my Lotus S2.. years go. Track use reasons.

Frustratingly these became noisy/rattly. surprisingly quickly.. Perhaps they weren't expensive enough? Dunno? only thing certain was it was annoying.

Once fitted out my old Saab with superflex bushes. After a few years living with them, I've been methodically pulling them out in favour of the simple oem rubber bits..achieving a better ride and surprisingly no apparent change in handling/response.

An expensive mistake, at least on this car.

[Mondo]

John,

Don't know if you remember this thread about teflon coated joints... it's what I'm going to do. I spray some motorcycle chain wax on them but the squeaking comes back after a couple hundred miles.

 

http://usa7s.net/vb/showthread.php?t=3624

[JohnK]

Mondo,

Yup, re. the thread you cite, and if you look you'll see a post by me about using a type of precision bolts to reduce the free play that can reduce the pounding due to clearance. I was worried about some sort of incompatibility that I hadn't yet heard of. Chain wax sounds like a good idea - well suited to staying put under severe conditions.

[Ian7]

I've used sphericals in my Lotus S2.. years go. Track use reasons.

Frustratingly these became noisy/rattly. surprisingly quickly.. Perhaps they weren't expensive enough? ...

 

I'd say you must have had some cheap ones if they developed clearance quickly.... sphericals on our formula cars last a season or more under tougher conditions.

As for why not on a street car, well, usually the build tolerances on a street car aren't tight enough to avoid additional stresses in suspension components that rubber bushings don't impart (rubber 'gives' in the appropriate direction to allow for this). The infinitely stiff, zero-play spherical just transfers the load to the weakest link in the system. Classic case is all the guys who change their live-axle car A-frame diff pivot to a spherical, then change it back when they get tired of welding up the diff ears over and over :-)

[danilo]

Likely they were mediocre quality, but in truth it Was in the mid 70's and the wife did run our / this S2 to national runner up in solo.

So it wasn't that poorly prepped or crap :-)

 

Just claiming, that in my experiences, a lot of 'stuff' can be more hype than reality.

Caveat emptor is a timeless concept.. apparently.