Thread: Poly bushes don't flex, do they..

Over 220,000km now and the Super Pro trailing arm bushes are still

functioning perfectly.

I might point out that the aftermarket concave rubber trailing arm bushes on my RRC were still going strong at about 180KK of touring towing etc on all the worst roads around.

I should qualify that I am really talking about rotating bushes such as Panhard Rod, rear trailing arm to axle, A frame to chassis. Look the reason for this post was not to rubbish Poly bushes but to inform maybe newer members of the theory behind both types of bushes.

If you can get poly bushes soft enough with the same durometer reading or better than Metallistic for bushes that do not move ( much) they should be good. However except for the few experiences on here and in your case on a 130 , every review I have seen with say Range Rovers, Discos etc have said they are unbearably harsh. Are the manufacturers so dumb that they keep on making stuff that is not what the market wants or is there a limitation to the technology?

They still seem to transmit more shock when used in say Shock bushes which are static. As a buyer you don't know what durometer reading they have and in my experience they are sometimes used to hide mistakes.

I bought a set of TJM shocks once and the rubber bushes flogged out in 1000k. They then sent me poly bushes which lasted but were unbearably harsh. The reason was that the shocks were just too stiffly valved for pin bushes which they covered with poly bushes.

I think I personally will stick with Metallistic but it is up to the individual what they want.
BTW , how often do the users of poly bushes pull them out and regrease them. It should be pretty often. I always thought that they would be OK even in twisting use if drilled bolts with grease nipples were available in the correct size so that you could regrease them every 2-5KK or so. Thats what they have for Toyotas and others with leaf spring shackles and IMHO would make them more acceptable. It also stops the squeaks.
Regards Philip A

Originally Posted by PhilipA

...However except for the few experiences on here and in your case on a 130 , every review I have seen with say Range Rovers, Discos etc have said they are unbearably harsh. ...

I don't know which reviews you are reading? Everyone on here (>50 people (probably closer to 200 people)) who has tried superpro has never gone back to rubber. They are nothing like the old fashioned hard piles of coloured plastic the UK mags sell.

Here are my OE radius arm bushes after 2000 km (Perth to Well 32 on the CSR).


http://i124.photobucket.com/albums/p...rip2010373.jpg

OE Trailing arm bushes at the end of the trip (CSR, GRR, etc, etc..):

http://i124.photobucket.com/albums/p...rip2010727.jpg

The SuperPro bush which replaced the rubber crap

http://i124.photobucket.com/albums/p...rip2010724.jpg

The SuperPro bushes have been fitted for 3 years of mainly offroad touring now.

IMHO Phillip is correct for joints that deform in rotation (torsional shear) such as for example the axle end of rear lower trailing arms.

With respect to those that crush such as chassis end of rear lower trailing arms or front radius arms of Defender RRC and Disco I, the design is the problem. I don't see the poly material being the better choice of material compared with decent (not cheap) rubber.

Where the superpro has the advantage is their design is better.

Land Rover went backwards with some of their design and constrained the rubber further than they were earlier. For example going to wider triple shell radius arm bushes and with the rear shockie bushes.

They would do well to copy what Nissan have done for GU radius arms or even those for 105 series Landcruisers (not as good as GU but much better than Land Rover. Nissan trailing arm bushes are better than Land Rover as well.

Rubber is virtually incompressible material, and the elastomers such as polyurethane are similarly bad. It deforms readily if there is space for the material to deform into, but take away the space and confine it is asking for trouble.

Rubber behaves as a brittle material under 3 dimensional stress, and this can occur where it is bonded to the steel components or where it is trapped such as the parts of Isuzurover's radius arm bushes. Bonding rubber to steel is an appropriate procedure, but provision has to be made for deformation, and adding the 3rd bonded shell to radius arm bushes not the way to go

Give me a properly designed bush made with decent rubber please.

Originally Posted by Bush65

IMHO Phillip is correct for joints that deform in rotation (torsional shear) such as for example the axle end of rear lower trailing arms.

With respect to those that crush such as chassis end of rear lower trailing arms or front radius arms of Defender RRC and Disco I, the design is the problem. I don't see the poly material being the better choice of material compared with decent (not cheap) rubber.

Where the superpro has the advantage is their design is better.

Land Rover went backwards with some of their design and constrained the rubber further than they were earlier. For example going to wider triple shell radius arm bushes and with the rear shockie bushes.

They would do well to copy what Nissan have done for GU radius arms or even those for 105 series Landcruisers (not as good as GU but much better than Land Rover. Nissan trailing arm bushes are better than Land Rover as well.

Rubber is virtually incompressible material, and the elastomers such as polyurethane are similarly bad. It deforms readily if there is space for the material to deform into, but take away the space and confine it is asking for trouble.

Rubber behaves as a brittle material under 3 dimensional stress, and this can occur where it is bonded to the steel components or where it is trapped such as the parts of Isuzurover's radius arm bushes. Bonding rubber to steel is an appropriate procedure, but provision has to be made for deformation, and adding the 3rd bonded shell to radius arm bushes not the way to go

Give me a properly designed bush made with decent rubber please.

Exactly. The problem in recent years is mainly the quality of the bushes. On the canning I put my old radius arm bushes back in, that were fitted for at least 10 years and 150k km!!! They lasted the rest of the trip without a problem. So as well as the poor design, the quality of the rubber and the quality of the bonding to the steel seems to have severely deteriorated.

I have Superpro bushes. This the flex in a stock 110 with stock length shocks and standard springs. I have been to the desert and back with the Superpro and no real wear to be seen.

Ressurecting an old thread... Sparesbox have 25% of Superpro products for the next few days

Regards,
Tote

I got a full set for my POS about 15 years ago from Paddocks. Was ridiculously cheap even with freight.

That may have changed with covid affecting freight charges so 25% off is a great deal.

All bushes are still fine. Front diff is now County with maxi axles, etc and I have new SP bushes for the diff housing to replace some other brand of poly that are caster correction.
My pet hate.

DL

One of the rear chassis bushes on the 130 is pretty loose after 100,000KM. I suspect this may be due to the nut not being tight enough from the factory and causing it to move around, I had to tighten it up on a trip last week as it was getting noisy so its time to do both rear ones. Price from sparesbox was about $150 for the kit.

Regards,
Tote