Proflex bushes and roll control

[tiddy1]

My understanding is that the Polyeurothane/ proflex type bushes do not distort like the rubber ones. i.e allow rotation, but stop axial motion. so If all the bushes in the rear end are replaced do they stop the rear end from rolling. Or do they transfer teh twisting into the radius arms and A-frame.

 

is it better therefore to replace A-frame front bushes and the radius arm front bushes with nylon and leave the De-dion tube centre bush and the radius arm rear bushas as rubber to allow the roll>

 

If this is the case do you need to reduce the anti roll bar stiffness or is the difference to small to notice

 

Simon

 

Edited by - tiddy1 on 5 Feb 2009 11:58:50

 

Edited by - tiddy1 on 5 Feb 2009 12:45:08

[Pendennis]

Nylon bushes would allow weight to be transfered more than a standard rubber bush as well as increase the transfer of vibration and sound through suspension arms.

 

I would recommend you change all the bushes, so the same.

 

In theory I'd of thought you need to increase ARB stiffness but that is something you could experiment with as Yes, you would notice the difference.

 

Replacing rubber to nylon would reduce suspension stiction thus improve performance significantly. The disadvantage is the additional stress on the chassis and suspension arms.

 

Where can you buy Nylon Proflex bushes then?

 

 

 

 

Want to rent an 18th century Farmhouse in Rural Somerset?

 

Edited by - Pendennis on 5 Feb 2009 12:42:19

[Martin S.]

thus improve performance significantly

Really.......if this is the case I wonder why Caterham don't fit them as standard or any sprint/race cars have them fitted

 

Class 4 Zetec

[Pendennis]

I don't know why Caterham fit them as standard either Maybe, they like to keep these things packaged compactly

 

But I do know why Mclaren don't fit rubber bushes to Lewis's car

 

Martin, removal of resistance from your suspension will only speed up suspension movement. Rod ends is probably the best method for Race Caterhams

 

Want to rent an 18th century Farmhouse in Rural Somerset?

[jono]

The Autobush poly bushes I have just bought (albeit for a classic Elan not a 7) seem to work in the opposite way to the std Caterham ones which rely on the twisting action of the bush being as it is bonded to the central metal sleeve.

 

The Autobush ones act like a flexible bearing where the stainless steel sleeve is clamped by the bolt and the bush rotates around it (aided by special grease which is suppleid with the bush).

 

I too am interested in the question as presumably this reduces some of the springing in the chassis which would have been provided by the fixed torsion type bush.

[tiddy1]

The one reason caterham may stick to the rubber type is the lack of maintanence, the poly/ autobush solutions need to be greased to ensure that the sleeve rotates in the bush so will need re-greasing

 

what I was more worried about was that the rubber bushes can twist along the axis of the bolt (i.e one end of the bolt goes up and the other and goes down) when in roll but the poly ones won't,

 

reading the blurb on the poly bush web site they only claim to be about 25% stiffer so they still probably allow some twisting

 

My current bushes are 15 years old so probably pretty solid!

 

Simon

[Jason Plato]

why Caterham don't fit them as standard or any sprint/race cars have them fitted

 

cost

 

and most club sprinters are not modified to any great extent, especially in the suspension department. Almost all purpose built race cars will have spherical bearings rather than bushes - nylon, poly or rubber .

 

One to bear in mind and one that concerns me and is a main reason I've not fitted poly bushes, using the dedion A fram forward mounts as an example, is that the metal sleeve is clamped by the suspension fixture on the chassis, in this case on one side as a bolt, as the sleeve in the bush can move sideways as well as rotate the A frame could easily flex sufficiently sideways under cornering to make metal to metal contact on the chassis ? or to create sufficient loadings to bind on the sidewall of the bush sandwiched between the A frame and chassis ?.

 

 

 

here is C7 TOP

Taffia joint AO with Al

 

[tiddy1]

As I understand it Dave the poly bushes have to be shimmed with large washers either side and greased so thatthe movement is between the washer and the bush and not the metal to metal parts.

 

I think standard bushes are the best bet

 

Simon

[Jason Plato]

Ahh OK

 

 

 

here is C7 TOP

Taffia joint AO with Al

 

[Jason Plato]

just like the ole trunions 😬

 

thats progress

 

here is C7 TOP

Taffia joint AO with Al

 

[Pendennis]

Has anyone purchased/fitted a set of Powerflex bushes to their S3

 

Want to rent an 18th century Farmhouse in Rural Somerset?

[taffyracer]

I am about to fit a set, I am a powerflex dealer but beyond that I have no direct experience with a 7 and these bushes, one thing I can say though is that from experience with many other cars, the powerflex bushes are always an improvement if the car is used hard, if I didn't rate them then I wouldn't be fitting them

 

http://www.xlraceparts.com

 

Edited by - taffyracer on 21 Feb 2009 13:32:19

[Pendennis]

Well before you do I think there is a few problems I should say, that is why I asked if anyone has fitted them yet.

 

Powerflex website shows the rear bush of watts linkage as a large, it isn't it is a small.

The other problem is I can't see how the small bush as used in the front top wishbone can also work in the watts linkage. As it appears that the inner steel sleeves of the poly bush, pivot over the Powerflex retaining bolt pin. Problem is, when used in the watts linkage the Powerflex retaining bolt pin is the wrong size, thread and length. Also, if we utilise the existing Caterham bolt this would cause (when secured tightly) the poly washer and bush to bind upon female Caterham boss on the chassis. Also, the bore of this small bush is larger than the Caterham bolt, the female threaded Caterham bosses on our watts linkage chassis points are 3/8 and not 8mm as Powerflex thinks. Unless I am going mad, they can't work ☹️

 

Want to rent an 18th century Farmhouse in Rural Somerset?

 

Edited by - Pendennis on 21 Feb 2009 14:07:50

[taffyracer]

Ok, i've passed your comments over to Powerflex for comment

 

http://www.xlraceparts.com

 

Edited by - taffyracer on 21 Feb 2009 14:26:33

[6speedmanual]

Rubber bushes good.

 

No lube.

 

Maintenance free.

 

Accommodate small misalignments in chassis and suspension members.

 

Hysteresis.

 

When small (as bushes on 7) they are also pretty stiff.

 

 

Peter

 

 

 

6SpeedManual

*tongue*There's no such thing as too much BHP per Ton 😬

[Phil]

I had an Audi coupe, lowered and driven hard, every year I had to replace the four front lower arm bushes, cheap at about £4 each but about £30 a side to fit.

I took the plunge and swapped for Powerflex bushes, they were never replaced and lasted another six years before I sold the car on, I was never told they had to be lubricated and I never did.

The feel of the car was better after fitting the Powerfelx bushes as steering alignment was less effected under hard braking with the benefit of more even tyre wear.

I believe Powerflex need you to measure your bushes before ordering as they claim the 7 has had so many different sizes fitted over the years.

 

FreeRange7

 

http://good-times.webshots.com/photo/2404840560089816983khvSRw

 

[Pendennis]

Right, after a telephone conversation with a very nice man at Powerflex, between us we have got to the bottom of a compatability issue with their bushes on my Caterham 1997/8 S3 DeDion chassis. We are all aware there are variants in chassis

 

1). The PF8 - 901 large wishbone bush needs 1.5mm white washers 1/2" bore and not the 3mm as records show.

 

2). The PF8 - 902 small wishbone bush does not suit the watts linkage arms/lugs on our 97/98 Dedion Caterham chassis. The forward and rearward chassis female lugs which connect the watts linkage arms takes a 3/8" bolt, this needs to have a thread no longer than 30mm. So if the Powerflex supplied bolt/pin was to be utilised and instead had a 3/8" threaded section 30mm in length, this bush would then work on the Caterham chassis. (Currenty this Powerflex supplied bolt/pin has an M8 thread which is 15mm in length) thus no good.

 

3). On my 97/98 DeDion Caterham chassis the rearward bush on the watts linkage is a small type and not a large as shown on their website.

 

4). This comment on this thread is incorrect "As I understand it Dave the poly bushes have to be shimmed with large washers either side and greased so thatthe movement is between the washer and the bush and not the metal to metal parts"

 

The inner steel sleeve and bolt pin acts as a bearing. As it rotates/pivots over the Powerflex supplied bolt pin

Note: The poly bush is fixed to wishbone and the white poly washer is ONLY there to prevent the steel wishbone rubbing against the steel chassis pick up cup. The Powerflex supplied bolt/pin does not pull up tight against the Caterham chassis pick up cups, it is fabricated in such a manner that it just pulls up enough so it can't travel back and forth.

 

I hope this may be of help to others, preventing them experience what I have. Powerflex are reviewing their products as a result

 

Want to rent an 18th century Farmhouse in Rural Somerset?

 

Edited by - Pendennis on 23 Feb 2009 12:46:21

 

Edited by - Pendennis on 23 Feb 2009 12:47:41

 

Edited by - Pendennis on 23 Feb 2009 12:51:37