Polyurethane bushings

[rdssdi]

It is my understaanding that if the suspension arm attachment bolts are not torqued to spec they will incur additional and possibly excessive side loads. Leading to failure. To slacken the nut to allow a binding bushing to rotate could be a problem.

Bob

[RotoFlexible]

Continuing with discussion re criticality of fit-up with poly bushes, I found that I had to use large INNER washers (between wishbone and chassis studs) to stop bushes migrating in that direction. Anyone else had the same problem?

Gerry,

The flanges on these bushings should prevent inward migration, but if enough force is applied I suppose the flanges won't keep the bushing from moving in the sleeve. Stout washers on the outside should keep everything centered. I don't currently have a frame on which to trial-fit the arms but when I do, I'll be interested to see how much play there is with the arms bolted up to the ball joints (top) and trunnion and shock (lower). I hope there won't be any. If there is, I may need inside washers to take up the slack.

The outside washers will need to be carefully machined to be a snug fit on the spindles, so that the washer bears on the crush tube evenly.

[miked]

Andrew,
I think you will find that with "off the shelf" stainless washers you will achieve a good grip of the crush tube. They are required both sides of the bush. Re your photo with the bush assemble, the crush tubes need to be flush with the bush surface on both sides. If not they will bind. Assembled a crush tube in a bush and you will see this. If when put on the bone the crush tube is not flush, then it means your bone inner tube diameter is to tight (bush has migrated length ways). In the earlier post I mentioned this and in a post of a couple of years ago. They will need very slight reaming (if it is not just paint). If you assemble like this you will bind.

I found that after 2 years I had a bit of tightness in my nearside top and had to strip it and sort it is so that all moved when dogged up.

PS I bought some of those auto bush just for the hell of it and the price.

About ?60 with post (full car set). They look great. Even have the cross hatched rifle bore for the grease. Same grade of poly' and a full tube of grease in each pack set. I am struggling to see why they are not as good if not better than the others on sale. Full set is about ?250-300 if I recall.


Mike

[bilcoh]

Reviving an old topic here, as I haven't found the answers in the archive.

I'm considering a non-stock suspension bushing. My goal is a very direct feeling car for "spirited road" and the occasional track day, without going full rose-joints and rattling the car to pieces.

I found this and other threads from 2007 about Autobush, and Andrew Bodge among others that were fitting the bushings. Has anyone gone this route specifically (Autobush), and care to comment on handling as well as ride harshness? Comments about other bushing types/suppliers would be welcome as well.

Archivists, if you can point me to where this has been answered, I'd appreciate it, and will apologize for troubling everyone.

Thanks.

[RotoFlexible]

I'm considering a non-stock suspension bushing. My goal is a very direct feeling car for "spirited road" and the occasional track day, without going full rose-joints and rattling the car to pieces.

I found this and other threads from 2007 about Autobush, and Andrew Bodge among others that were fitting the bushings. Has anyone gone this route specifically (Autobush), and care to comment on handling as well as ride harshness? Comments about other bushing types/suppliers would be welcome as well.

I did fit the Autobush bushings. I have had no problems with them, and the ride seems fine. I also have slightly stiffer ("fast road" spec) springs, solid rack mounts, and CV jointed driveshafts, so I've done most of the mods that are said to result in a stiff, harsh ride, but it doesn't seem that way to me. (I'd love to compare my car to one in original trim, though - it might change my mind.)

I haven't had the car on the track, but on the road, the handling is excellent, no bad habits at all even at cornering speeds that seem well beyond reasonable to me.

[collins_dan]

Andrew, Just curious, what are you using for wheels and tires with that combination? Thanks, Dan

[RotoFlexible]

Original steel bolt-ons with 155R13 Vredestein Sprint+. I like the tires, but the original wheels are not quite straight (I had them straightened once) and have very small cracks at the apexes of the triangular cut-outs. I broke one of them on the track, long ago, and if I were ever to put the car back on the track, I'd want a set of Panasports. I get a bit of a vibration at 70mph, enough to discourage me from driving any faster.

[bilcoh]

Thanks, Andrew. You've done all the same mods that I'm anticipating, so I'm glad to hear you don't think the ride suffers. Agreed, though, that you might change your mind in a blind test.

A couple more questions if you're willing:

- On the bushings, are they a hard compound or do they have some pliability? I mentioned in another post that way back when, I machined Delrin for the rear bushes. It's a solid material with no give to speak of when you're working with it. Basically, it looks and feels like a rod of plastic. Are the Autobush items similar, or can you "squeeze" them, implying there's a little give? Mostly just trying to determine how much harder the Delrin might be, and thus how much more harsh the ride might get.

- What are you running for your spring rates, front/rear? I've got TTR dampers to install on both ends, but haven't made a spring purchase yet. I'll search the archives, but since your mods seem to indicate a similar mindset about the car, I'd be interested in your choices and subsequent observations.

Thanks,

Dave

[miked]

I have auto bush on a plus 2 with standard set up (apart from rear Koni adjustable damper set up a tad). Yes, you can squeeze them. They are relatively soft. I have completed about 800 miles and find them great. The ride quailty is fine and not harsh. In mid bend, going on and off the throttle, does not appear to invoke any rear problems. They seem no different in hardness/softness than the Superflex bushes (apart from the cost).

In time, I will be uprating to fast road springs and front adjustable as I am just a bit soft for my liking on the smaller road fast bends. No track use intended.

[RotoFlexible]

- What are you running for your spring rates, front/rear? I've got TTR dampers to install on both ends, but haven't made a spring purchase yet. I'll search the archives, but since your mods seem to indicate a similar mindset about the car, I'd be interested in your choices and subsequent observations.

I think I have the TTR "fast road" springs/dampers on the front ("think" because I sourced them through RD Enterprises in the US). I ordered equivalently stiffer springs from Dave Bean for the rear with an adjustable perch setup. I haven't touched the front damper settings and left the new Koni rear inserts on their factory setting, the softest I believe.

I have auto bush on a plus 2 with standard set up (apart from rear Koni adjustable damper set up a tad). Yes, you can squeeze them. They are relatively soft. I have completed about 800 miles and find them great. The ride quailty is fine and not harsh. In mid bend, going on and off the throttle, does not appear to invoke any rear problems. They seem no different in hardness/softness than the Superflex bushes (apart from the cost).

I'll second this, especially the absence of trailing-throttle oversteer. I certainly noticed that characteristic on the track with my original bushings!

[elansprint71]

Pat Thomas at Kelvedon has some new poly-bushes which, unlike other types, are visually like the originals, i.e. steel outer, resilient material, steel inner. Might be worth a look, they don't call him the Elan guru for nothing!

http://www.kelsport.net/

[Sea Ranch]

Great discussion. Thanks.

I take it from what I'm hearing that, for a guy who's highest value is a supple ride (don't like noise, vibration, harshness, rattling), original-style bushing are the way to go. No?

[elansprint71]

Great discussion. Thanks.

I take it from what I'm hearing that, for a guy who's highest value is a supple ride (don't like noise, vibration, harshness, rattling), original-style bushing are the way to go. No?

In the short term, possibly, but as modern"rubber" seems to have a very short life due to the banning of certain hazardous substances previously used, unless you want to change the bushes every couple of years some form of poly is probably a better option.

[Sea Ranch]

So Peter, you'd say the current crop of rubber bushing is that bad: about a 2/3 year life span?

[miked]

Plus 2 outer rear are not good at all. Not much rubber and if you don't do the ride height thing they get ripped up. Come to think, even with correct setting they soon shear. Mike