14 replies to this topic

[Teapot]

Poly bushes front, rubber rear, 2 years old. Is the rubber one pooped? Same other side.

[petey81]

oh yeah like a pancake lol

[Jordie]

Yes definately would be replacing that, even if no movement present.

[tiger99]

Well, it will do that, because the poly can not compress significantly, so the compression, which is necessary to allow tie rod angular movement, will all happen in the rubber. With two rubbers fitted it would happen half in the front and half in the rear rubber, but what happens with poly is that a wedge-shaped gap appears between poly and mount under extreme deflection, and the remaining rubber has to compress twice as much as normal.

I would not be too disappointed about having to change them every 2 years as it is quite easy. But what was the mileage, which is of more importance?

[Teapot]

Excellent, thanks. About 1,500 miles. Can you say a bit more about the stresses involved? I wonder if I should be making more provision for 80+ bhp with 4.5 x 10s.

[tiger99]

1500 miles is disappointing. Were they genuine rubbers? I think you should go back to all rubber, using only genuine parts, and see how they do. All poly is no good as the tie rods or the mounts will break. Your power output is not excessive so that is not the cause, nor are the proper size wheels.

[Ethel]

Minispares do uprated rubber ones.

[Cooperman]

You do really need rubber both sides and the Mini Spares slightly harder rubber ones are ideal. With poly both sides there is a risk of the sub-frame 'ears' failing due to having loads applied which they were not designed to take. Ever seen a broken off 'ear'? It ain't pretty!

[Teapot]

Thanks for that. I recall buying this set, C-STR627, from Minispares based on the advice given with it:

"Use 2 Soft rubbers on the insides and the 2 Mauve poly on the outside.
HARD OUTERS / SOFT INNERS - STOPS BRAKE WEAVING.
Don't be confused as this set up was proven after 2 years of testing and is perfect for race and road, having now been sold for over 10 years with success."

This theory of hard outside/soft inside is repeated in the blurb with part C-STR628, a hard rubber bush, but says it applies to "large tyres."

So it's the harder rubber C-STR628 for all 4, right?

[jamiestevenbell]

I know I'm digging up an old thread but I have had exactly the same from my mini spares bushes that are 2k old one even passed over the stop on the tie bar and minispares said I must have fitted it that way!!! Ye rite as ya would! Was there ever a dodgy batch of these sent out with the hole too big?

[firstforward]

Most probably, there are many issues with suppliers selling most rubber items as poor quality and not fit for the purpose, they need to address this point as it is unacceptable.

[Cerberus]

Just to add to this, I've not had any problems with my minispares tie bar bushes, and have done well over 2k miles, getting on for 10k+ on them.

 

 

Could it be that the tie bar nuts are being done up too tight, causing the rubber to compress too much to begin with?

[Dan]

Not really because the shaft is shouldered and the nut stops at that point. In fact the poly bush in these kits is made shorter than standard to prevent the poly overloading the rubber, if you do this with any old poly bush though that could be a problem. I've been using this setup for 5 or 6 years or more without an issue.

[Cerberus]

Is that nut on the end supposed to be done up till it stops then?

[GraemeC]

Yes.