Tasmin Trailing Arm Design Improvements
Discussion
Thread resurrection!
Bushes on my arm came up as an advisory on the last MOT. has anyone got any comments on the suggestions on this thread?
Powerflex bushes, the billet thingy, not going to try the whole redesigning the rear, but looking for suggestions. I'd also be quite happy to stick with the normal ones.
Any ideas welcome guys
Cheers
Marcus
Bushes on my arm came up as an advisory on the last MOT. has anyone got any comments on the suggestions on this thread?
Powerflex bushes, the billet thingy, not going to try the whole redesigning the rear, but looking for suggestions. I'd also be quite happy to stick with the normal ones.
Any ideas welcome guys
Cheers
Marcus
Hi Marcus...The OEM are okay...They have lasted this long...I used the Superflex purely as they were a bit more heavy duty...Obviously a bit more expensive...What ever you choose make sure you replace both sides at the same time and also the pins...Clean up any crud on the arm where the shank of the bolt sits....And always make sure that they are finally bolted up with the weight of the car on them...Ideally a ramp and not an arm lift....Ziga
I've looked at mine a few times, and thought the same thing - From what I see, the main issue is that the force resolves down the pin, into a squishy bush at an offset to the line of 'pull'. Therefore either the bush distorts and wears out, and /or the pin will bend. The pin itself is also a problem as it has a thinner part with a shoulder exactly where the force transfers ....
One of the pins in my car was bent, and bush was knackered.
Ideas - the simplest ideas which occur
1) The main bush should be IN THE TRAILING ARM - similar to the way it fits in a leaf spring. Force is then all through the bush which is properly supported. Bolt then supported at both ends in a U bracket, again just like a leaf spring shackle. You might even be able to bolt a U bracket to existing mount ??
2) it would probably help if the pin was same diameter all along (and you would only have to change the bush to do this). doesn't help much with distortion, but pin less likely to flex/bend.
3) rose joint at end (this from a thread here).
4) change it completely, or move trailing arm to outer chassis rails (may need some extra braces - sort of under seats ?)
Comments ? Interested in everyone's ideas.
One of the pins in my car was bent, and bush was knackered.
Ideas - the simplest ideas which occur
1) The main bush should be IN THE TRAILING ARM - similar to the way it fits in a leaf spring. Force is then all through the bush which is properly supported. Bolt then supported at both ends in a U bracket, again just like a leaf spring shackle. You might even be able to bolt a U bracket to existing mount ??
2) it would probably help if the pin was same diameter all along (and you would only have to change the bush to do this). doesn't help much with distortion, but pin less likely to flex/bend.
3) rose joint at end (this from a thread here).
4) change it completely, or move trailing arm to outer chassis rails (may need some extra braces - sort of under seats ?)
Comments ? Interested in everyone's ideas.
Edited by RCK974X on Thursday 25th February 22:12
I think what John Halstead did on the now orange 350i is the best solution...Its an early 350i with trailing arm suspension but now has a serious rear suspension set up...
Ill see if i can find the thread......
Here we go...How fitting the porn is on page 3....
http://www.pistonheads.com/gassing/topic.asp?h=0&a...
Ill see if i can find the thread......
Here we go...How fitting the porn is on page 3....
http://www.pistonheads.com/gassing/topic.asp?h=0&a...
Edited by mrzigazaga on Thursday 25th February 22:48
I have my trailing up rose bushed, and works very will with my 240 BHP Rv8 And LSD, going to be 300BHP soon.
don't have pic;s as not at home, but I sure I posted some if you want to look at my posts.
I run a data logger and get 1.3g+ on the track which is the same as my breaking G force, so I guess the limit is the tires.
don't have pic;s as not at home, but I sure I posted some if you want to look at my posts.
I run a data logger and get 1.3g+ on the track which is the same as my breaking G force, so I guess the limit is the tires.
Assuming it's the photos I saved, the rose joint setup is very neat !!
One thing I did notice on the link Zig posted is that the bearing 'plate' solution still has the forces resolving down the 'pin', and it's not clear if that pin is bigger - not knocking the solution, but it seems to really only replace the bush, so other issues still present ?
(unless I am misunderstanding it)
Rose joint looks better solution to me, but more work involved....and anyone with better engineering experience tell me otherwise ?
One thing I did notice on the link Zig posted is that the bearing 'plate' solution still has the forces resolving down the 'pin', and it's not clear if that pin is bigger - not knocking the solution, but it seems to really only replace the bush, so other issues still present ?
(unless I am misunderstanding it)
Rose joint looks better solution to me, but more work involved....and anyone with better engineering experience tell me otherwise ?
I started on the job yesterday, planning to remove the old ones today. What do you think of them, bit of a state and need replacing right! They havent failed and the car drives / handles fine.
So i'm going to have to put it all back together today and swap the wedge over with the little german stablemate that left me stranded yesterday.
The count of strandings in the last two years is now...Germany 3 England 1.
VorsprungBlackpooltechnic.
I'll come back to this once the TT is fixed.
Cheers
Marcus
When you google 'wedge trailing arm' and find your own picture!
The photo at the beginning of the thread I took when embarking on rebuilding my own 350i nearly 5 years ago.
It's since had TWO sets of rear trailing arm bushes.
The first set, from a Sheffield based specialists, were totally unfit for purpose. I managed to tear the centres out in around 5000 miles.
I've since replaced them with Superpro bushes which seem much, much better, and have survived so far.
The big problems I've experienced with the trailing arm set up s how incredibly sensitive it is to the location and trimming of the pivot point.
I can tell, for example, if the bush retaining plates have come loose by even a few millimeters.
At some point, I'd like to investigate the possibility of using spherical bearings.
These have the advantages of rose joints, but are sealed, so can be used in all weathers.
Bob.
The photo at the beginning of the thread I took when embarking on rebuilding my own 350i nearly 5 years ago.
It's since had TWO sets of rear trailing arm bushes.
The first set, from a Sheffield based specialists, were totally unfit for purpose. I managed to tear the centres out in around 5000 miles.
I've since replaced them with Superpro bushes which seem much, much better, and have survived so far.
The big problems I've experienced with the trailing arm set up s how incredibly sensitive it is to the location and trimming of the pivot point.
I can tell, for example, if the bush retaining plates have come loose by even a few millimeters.
At some point, I'd like to investigate the possibility of using spherical bearings.
These have the advantages of rose joints, but are sealed, so can be used in all weathers.
Bob.
the pin through my set up is 20mm 12.9 cap head bolts so way stronger, even with a rose joint on the arm it still needs a bolt/pin to attach to the chassis must say i like the rose joint solution just liked the self aligning spherical bearing as it uses two of the original holes just need the opposite one to form the square bolting arrangment.
john
john
Don't know how old and cold this thread is. After poking around with this on both a 280i and Lotus Europa, I did design an aluminum clamshell/spherical bearing design that works great. After surveying what the racing crowd seemed to have done successfully to optimize this suspension design on the TVRs and Lotus Europas, I came up with this for my '85 S 1.5 280i. A spherical bearing is the typical solution, but done in a few different ways. In this case, each half of the alloy clamshell fits over the metal frame mounting plate and captures the large spherical bearing. The reliefs in the clamshell provide travel clearance. Had a race prep shop do something similar to this for a full-on track-only Lotus Europa (would have been nice to fit a modern sports or formula racing car suspension and Hewland transaxle, but didn't go that far).
All fits in the stock location and retains all stock dimensions. It does eliminate the evil stepped pin for a straight/single-sized bolt, which eliminates that fragile step in the stock arrangement.
Oh, the only other thing that's popularly done to optimize this Lotus/TVR rear suspension design is to relieve the axial loading/wheel location duty from the drive axle. This is done just by adding a lateral link aligned precisely with the drive axles. With the TVRs, this link is fitted between the diff carrier frame/bracket and the hub/bearing carrier. Did this on the Europa (pre-built part from Richard Winter of Banks Europa); didn't do this with my 280i.
All fits in the stock location and retains all stock dimensions. It does eliminate the evil stepped pin for a straight/single-sized bolt, which eliminates that fragile step in the stock arrangement.
Oh, the only other thing that's popularly done to optimize this Lotus/TVR rear suspension design is to relieve the axial loading/wheel location duty from the drive axle. This is done just by adding a lateral link aligned precisely with the drive axles. With the TVRs, this link is fitted between the diff carrier frame/bracket and the hub/bearing carrier. Did this on the Europa (pre-built part from Richard Winter of Banks Europa); didn't do this with my 280i.
Edited by m2500tvr on Tuesday 28th March 01:31
Edited by m2500tvr on Tuesday 28th March 01:33
I have all my suspension photo's with rose joints up in one of my FB albums
https://www.facebook.com/leigh.jones.587/media_set...
https://www.facebook.com/leigh.jones.587/media_set...
TVRleigh_BBWR said:
I have all my suspension photo's with rose joints up in one of my FB albums
https://www.facebook.com/leigh.jones.587/media_set...
Thanks - I'll take a look. How did it change the ride characteristics? Ad did you do the work yourself?https://www.facebook.com/leigh.jones.587/media_set...
your need to add me as a friend on FB, to see my photos
AFAIK all the work was done by Moore Racing, all I did was renew everything. I never got round to getting it all set up professionally, but as said the data logger G readings was the same for braking as they was for cornering, so I think I was on the limit of the tires anyway.
It was over 1.3G which is better than the latest 458 Ferrari all being that's with them on road tires. a fully setup race Cerbera is 1.6G+
but it's feels really planted, and better than my 400SE,
not sure what's it would be like on the road, but the last race I did, after having the shocks serviced, and all now wheel bearings, and fixing the front turret. it felt as smooth as glass.
AFAIK all the work was done by Moore Racing, all I did was renew everything. I never got round to getting it all set up professionally, but as said the data logger G readings was the same for braking as they was for cornering, so I think I was on the limit of the tires anyway.
It was over 1.3G which is better than the latest 458 Ferrari all being that's with them on road tires. a fully setup race Cerbera is 1.6G+
but it's feels really planted, and better than my 400SE,
not sure what's it would be like on the road, but the last race I did, after having the shocks serviced, and all now wheel bearings, and fixing the front turret. it felt as smooth as glass.
TVRleigh_BBWR said:
your need to add me as a friend on FB, to see my photos
AFAIK all the work was done by Moore Racing, all I did was renew everything. I never got round to getting it all set up professionally, but as said the data logger G readings was the same for braking as they was for cornering, so I think I was on the limit of the tires anyway.
It was over 1.3G which is better than the latest 458 Ferrari all being that's with them on road tires. a fully setup race Cerbera is 1.6G+
but it's feels really planted, and better than my 400SE,
not sure what's it would be like on the road, but the last race I did, after having the shocks serviced, and all now wheel bearings, and fixing the front turret. it felt as smooth as glass.
I can't find reference to Moore Racing online - do you have any contact details?AFAIK all the work was done by Moore Racing, all I did was renew everything. I never got round to getting it all set up professionally, but as said the data logger G readings was the same for braking as they was for cornering, so I think I was on the limit of the tires anyway.
It was over 1.3G which is better than the latest 458 Ferrari all being that's with them on road tires. a fully setup race Cerbera is 1.6G+
but it's feels really planted, and better than my 400SE,
not sure what's it would be like on the road, but the last race I did, after having the shocks serviced, and all now wheel bearings, and fixing the front turret. it felt as smooth as glass.
Thanks
Reading a car mag last week and found a write-up for this company. Drop a custom sized (width) Corvette rear end in place of the the current cage for a (superficially) reasonable amount of money. No idea how one would tie it into the current frame but where there is a will... And they are doing a front end kit too.
Even if is not practical, It's worth a peek, scroll down: http://www.dobbertinperformance.com/
Even if is not practical, It's worth a peek, scroll down: http://www.dobbertinperformance.com/
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