Trailing Arm & Poly bushes
Discussion
Does anyone supply an uprated trailing arm bush in polyeurathane or can you only get standard trailing arm bushes? The ones on the 390 need replacing.
Also, Ive done a search on poly bushes and no-ones appears to supply a full kit, although superflex supply a lot. Where are people getting their poly bushes from?
Nick
What started out as a simple refurb has now turned into a full body off restoration!!!!
Also, Ive done a search on poly bushes and no-ones appears to supply a full kit, although superflex supply a lot. Where are people getting their poly bushes from?
Nick
What started out as a simple refurb has now turned into a full body off restoration!!!!
zcar said:
Does anyone supply an uprated trailing arm bush in polyeurathane or can you only get standard trailing arm bushes? The ones on the 390 need replacing.
Also, Ive done a search on poly bushes and no-ones appears to supply a full kit, although superflex supply a lot. Where are people getting their poly bushes from?
Nick
What started out as a simple refurb has now turned into a full body off restoration!!!!
How big is the bush?Also, Ive done a search on poly bushes and no-ones appears to supply a full kit, although superflex supply a lot. Where are people getting their poly bushes from?
Nick
What started out as a simple refurb has now turned into a full body off restoration!!!!
You can look at the universal range in the demon tweeks catalogues which give you a number of dimensions to play with. What OD tube does it fit into?
N.
TVRleigh_BBWR said:
Not got any on mine it's fully rose jointed.
Whats the mechanics of rose jointed suspension and what are the benefits Leigh?Drop me an email if you dont want to hijack the thread
Id be interested to know about the full poly kit as it is definitely something I will be getting for mine at some point
Right where to start?......
Front suspension. Don't use poly, use the original wishbone rubber bushes because the suspension needs some movement to work correctly. Poly versions of the tie rod bush are worth it though.
The rear A frame is not an problem.
Trailing arm is more difficult and I would talk to someone like RT Racing who may have done some poly bushes.
Rose jointing is simple in practice: replace each bush with a rose joint by replacing the bush holder with a threaded bush. It removes compliance and stiffens up the suspension at the expense of making the ride harder and noisier. However, rose joints offer more movement than bushes which means that care has to be taken to ensure that the rose joint doesn't start to cause issues elsewhere. For example... on the front suspension, the SEACs have a big rose joint on the bottom chassis point which attaches to the wishbone through a big metal plate that is welded to a cutoff wishbone. The small design flaw with this setup is that the wishbone actually twists more than with a rubber bush and while it provides an advantage of adjustable camber it is at the expense of poor dynamic geometry. I had terrible problems with my setup which is why it got changed to my own design.
Front suspension. Don't use poly, use the original wishbone rubber bushes because the suspension needs some movement to work correctly. Poly versions of the tie rod bush are worth it though.
The rear A frame is not an problem.
Trailing arm is more difficult and I would talk to someone like RT Racing who may have done some poly bushes.
Rose jointing is simple in practice: replace each bush with a rose joint by replacing the bush holder with a threaded bush. It removes compliance and stiffens up the suspension at the expense of making the ride harder and noisier. However, rose joints offer more movement than bushes which means that care has to be taken to ensure that the rose joint doesn't start to cause issues elsewhere. For example... on the front suspension, the SEACs have a big rose joint on the bottom chassis point which attaches to the wishbone through a big metal plate that is welded to a cutoff wishbone. The small design flaw with this setup is that the wishbone actually twists more than with a rubber bush and while it provides an advantage of adjustable camber it is at the expense of poor dynamic geometry. I had terrible problems with my setup which is why it got changed to my own design.
shpub said:
Right where to start?......
Front suspension. Don't use poly, use the original wishbone rubber bushes because the suspension needs some movement to work correctly. Poly versions of the tie rod bush are worth it though.
The rear A frame is not an problem.
Trailing arm is more difficult and I would talk to someone like RT Racing who may have done some poly bushes.
Rose jointing is simple in practice: replace each bush with a rose joint by replacing the bush holder with a threaded bush. It removes compliance and stiffens up the suspension at the expense of making the ride harder and noisier. However, rose joints offer more movement than bushes which means that care has to be taken to ensure that the rose joint doesn't start to cause issues elsewhere. For example... on the front suspension, the SEACs have a big rose joint on the bottom chassis point which attaches to the wishbone through a big metal plate that is welded to a cutoff wishbone. The small design flaw with this setup is that the wishbone actually twists more than with a rubber bush and while it provides an advantage of adjustable camber it is at the expense of poor dynamic geometry. I had terrible problems with my setup which is why it got changed to my own design.
Ahhhh thanks for the info Steve, its always nice to learn a little something from time to time!Front suspension. Don't use poly, use the original wishbone rubber bushes because the suspension needs some movement to work correctly. Poly versions of the tie rod bush are worth it though.
The rear A frame is not an problem.
Trailing arm is more difficult and I would talk to someone like RT Racing who may have done some poly bushes.
Rose jointing is simple in practice: replace each bush with a rose joint by replacing the bush holder with a threaded bush. It removes compliance and stiffens up the suspension at the expense of making the ride harder and noisier. However, rose joints offer more movement than bushes which means that care has to be taken to ensure that the rose joint doesn't start to cause issues elsewhere. For example... on the front suspension, the SEACs have a big rose joint on the bottom chassis point which attaches to the wishbone through a big metal plate that is welded to a cutoff wishbone. The small design flaw with this setup is that the wishbone actually twists more than with a rubber bush and while it provides an advantage of adjustable camber it is at the expense of poor dynamic geometry. I had terrible problems with my setup which is why it got changed to my own design.
My concern is the trailing arm front bush bolt. I got my 5 speed gearbox from a Tasmin wrecked by the bolt snapping so have been investigating the rose joint. Doesn’t seem that difficult to do. Just choosing the right joint from the large number that seems to be out there, find a competent welder (I’m only at ugly weld grade) and separate the body from the chassis.
I have 2 spare bushes but they have no markings but RT used to advertise the bushes.
Don’t forget to buy new bolts as well.
I have 2 spare bushes but they have no markings but RT used to advertise the bushes.
Don’t forget to buy new bolts as well.
The trailing arm was designed for a europa and uses the same bush as the early ones,Lotus people have made many mods for them ,they did make it as far as the esprit and the mods for these might fit, some race cars run on solid brass bushes but they do not perform so well on potholes,the weakness is not just in the bush but also in the spindle which bends quite easily if pushed,but it adds character and gives the rear wheels the freedom to roam which is important for wedgers and erm free range chickens. Tempus 
I'vev put poly bushes on the trailing arm 350i I have, excepting the front one which is the original big rubber thing.
When you go poly you can only reassemble one way because the bushes allow very little lateral movement. I think I have to install the bottom link inboard bolt last of all. After this, if you want to work on anything you have to remove this bolt first.
When you go poly you can only reassemble one way because the bushes allow very little lateral movement. I think I have to install the bottom link inboard bolt last of all. After this, if you want to work on anything you have to remove this bolt first.
MJG280 said:
My concern is the trailing arm front bush bolt. I got my 5 speed gearbox from a Tasmin wrecked by the bolt snapping so have been investigating the rose joint. Doesn’t seem that difficult to do. Just choosing the right joint from the large number that seems to be out there, find a competent welder (I’m only at ugly weld grade) and separate the body from the chassis.
I have 2 spare bushes but they have no markings but RT used to advertise the bushes.
Don’t forget to buy new bolts as well.
I've got the body off the RC, and will have for a few weeks, your welcome to come down and see how the rose joints fit.I have 2 spare bushes but they have no markings but RT used to advertise the bushes.
Don’t forget to buy new bolts as well.
tempus said:
...some race cars run on solid brass bushes but they do not perform so well on potholes,the weakness is not just in the bush but also in the spindle which bends quite easily if pushed,...
My 350i was eating rear trailing arm bushes pretty quickly so I made up a steel block that mounted to the frame using the same two mounting bolts, and had a large hole bored to hold a brass bush (stepped hole so bushing presses in from one side, but stays seated. Works very well. Did this a few years back and it has done well. One mod I did in the process is I moved away from the original stepped bolt design, to a single high grade bolt that has a larger diameter. The stepped bolts have failed on my twice - one time during a fairly quick corner (not recommended). If of interest I will see if I can find photos.
We decided to junk the trailing arm and go for an a frame design, similar to what the later wedgies use, but not exactly the same, as we are trying to get the suspension loads back down the central spine chassis tubes rather than having them wafting about mid tube ala TVR design.
Nick
Nick
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