suspension bushes

[trader]

I've read just about all there is to read on replacing suspension bushes with urethane and still not clear if my cars ready for it. I've done 95000 kms fairly hard and with heavy wheels (16.3 kgs with tyre -I think standard was about 12). There is no visual wear on the bushes but I'm sure car is bashing and crashing over bumps more than it used to. Feedback please on at what K's you changed your bushes and whether there was a noticable change if you did it at low K's. My car is 16 years old now and I presume they would have hardened in that time. Anyone in Canberra done a changover?

[StanTheMan]

about 220k km

I found a massive difference between cars which had traveled say 150k km and say 200k km

clunks can also be associated with bad shocks & loose bolts in the suspension

[Mr Morlock]

Stans comments make sense to me. Perhaps check and or replace the shock absorbers before considering replacing all bushes. I suspect, but without evidence, that the bushes have a very long life and 100km is not really a long innings.

[Okibi]

It's a tricky question to answer because like dampers the bushes degrade slowly so choosing at what point you decide to change them can be personal preference (up to the point of complete failure).

(Obviously the newer they are the safer they will be - well derrr .. )

You also have to consider that they're made of rubber, so like a set of tyres, they might not be worn out with over use but they may have hardened with age, km's travelled isn't the only factor.

[greenMachine]

Wrong question.

Right question: Do I want to sharpen up my steering response and general handling?

While you have bushes that are stopping metal-to-metal contact, you probably don't need new bushes (of any sort) (OK - an exaggeration, but you get my drift). Up to that point it is a purely subjective decision, dríven by your budget, handling preferences etc.

I replaced mine when I started supersprinting, put in the stiffer of the two Superpros (with adjustable bushes), and was AMAZED at the improved sharpness in the steering and handling. I had earlier put in a set of Bilstein PSS9s, but the impact of the Superpros was qualitatively greater. I'd offer you a drive, but the GM has just been returned to stock, the bushes and PSS9s are in the new racecar....

Talk to Dave or Russell at Carco, they can probably point to someone who has done it and could give you some firsthand feedback/advice.

Oh, and if it is 'bashing and crashing over bumps', it almost certainly need new shocks... that would be my suggestion for your first step.

Your heavy wheels will increase the work the shocks are called on to perform, in your case by 25% apparently. As well as the extra weight affecting the ride and handling, trying to tame that additional energy from the increased wheel weight will wear your shocks out more rapidly.

[Juffa]

Hey Trader,

I have installed super pro bushes on each of the 3 MX-5s that I have owned. One of the best upgrades that I have done. On the 2nd 5 I installed the bushes at the same time as new shocks/springs (Koni/Eibach, I think)). I then removed the shocks/springs when I sold the car, but left the bushes on. With a cheap set of non-oem shocks installed it still rode very well. I change the bushes on that car at about 190,000Km and the other two at about 100,000Km.

In my experience the super pro bushes actually gave a more complaint and controlled ride. I believe this is because the old bushes had become very hard with age and the new bushes were more compliant in comparison.

J

[trader]

thanks for all the info - I will follow up with Russell Green Machine. I think I will try and get a ride with someone before I start this project. I have Konis and standard springs so will fiddle with those a bit. today I did the easy bit - changed out the swaybar bushes and that quitened things up a bit. I'm just looking making my car handle the best it possibly can.

[tbro]

I checked the bushes on my car yesterday, 114000ks and they are absolutely knackered.

For a car pampered and only dríven to church on Sundays I was quite surprised that they where stuffed.

Luckly I already have the front and rear bushes in the shed.

Oh! and I'm not talking about the clubman, I'm talking about "Scooter"

So another job to do!!

Terry

[grump]

Wrong question.



While you have bushes that are stopping metal-to-metal contact, you probably don't need new bushes (of any sort) (OK - an exaggeration, but you get my drift). Up to that point it is a purely subjective decision, dríven by your budget, .

Do you honestly believe this statement , or are you just pulling our legs.

[trader]

Russell gave me a drive of their awsome (turboed) red MX yesterday. It has bilsteins and super pros. While the
billies are much firmer than where I have my Konis set, there was an underlying tightness which I put down to the bushes. I am going to have a go at changing them in the near future. Stilll can't get over the raw power of the car after mine.