A Frame Adjustable Turnbuckle

PostPost by: bitsobrits » Tue Dec 29, 2020 7:43 pm

vstibbard wrote:Graeme,

I'm intrigued, is that a kit to make up an adjustable end for a front or rear wishbone with a bush rather than rose joint aka 26R?

I've been thinking about doing that for an Elan I'm running on the road and track and don't want the harshness and maintenance of rose joints.

Vaughan


Vaughan

I bought some TRR racing adjustable rear wishbones, then bought the sleeved threaded type ends (forget from where) which allowed for standard type bushes. Thought I had the best of both, so to speak. But it turns out that if the two bushed adjustable ends aren't in exact alignment, you get significant binding. In other words, if you set the wishbones up for zero toe in, they work fine, but once you shorten the front adjustable bushing to get some toe in, then your have to distort both the front and rear inner bushings to get the pivot bolts installed. Not a good solution.

So I changed the inner pivots over to rose joints and it's all good.

BTW, I've been running TTR rear wishbones with rose joint inner pivots and spherical bearing outers for the better part of a decade in my S1 Elan, on the street, and I do not find any issue with any 'harshness'. Suspension on that car is TTR fast road spec, so somewhat stiffer than stock springs/dampers.
Steve

Elan S1 1963-Bourne bodied
Elan S3 1967 FHC pre airflow

Formerly:
Elan S1 1964
Elan S3 1966 FHC pre airflow
Elan S3 1967 FHC airflow
Elan S4 1969 FHC
Europa S2 1970
Esprit S2 1979
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PostPost by: 661 » Tue Dec 29, 2020 8:35 pm

bitsobrits wrote:
vstibbard wrote:Graeme,

I'm intrigued, is that a kit to make up an adjustable end for a front or rear wishbone with a bush rather than rose joint aka 26R?

I've been thinking about doing that for an Elan I'm running on the road and track and don't want the harshness and maintenance of rose joints.

Vaughan


Vaughan

I bought some TRR racing adjustable rear wishbones, then bought the sleeved threaded type ends (forget from where) which allowed for standard type bushes. Thought I had the best of both, so to speak. But it turns out that if the two bushed adjustable ends aren't in exact alignment, you get significant binding. In other words, if you set the wishbones up for zero toe in, they work fine, but once you shorten the front adjustable bushing to get some toe in, then your have to distort both the front and rear inner bushings to get the pivot bolts installed. Not a good solution.

So I changed the inner pivots over to rose joints and it's all good.

BTW, I've been running TTR rear wishbones with rose joint inner pivots and spherical bearing outers for the better part of a decade in my S1 Elan, on the street, and I do not find any issue with any 'harshness'. Suspension on that car is TTR fast road spec, so somewhat stiffer than stock springs/dampers.


That's a very ineteresting observation, Steve. It makes sense and not something I'd considered. Perhaps rose joints on the inner joints and polybushes on the outers.......hmmmmmm
Graeme
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PostPost by: elancoupe » Tue Dec 29, 2020 9:35 pm

I have adjustable rear arms, with bushings in the threaded inboard adjusters, and have not experienced binding when adjusting toe in.

I actually have the same arrangement on both upper and lower front arms, also without binding. A fair amount of adjustment was needed for proper caster, I have experienced no issues.
Mike
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PostPost by: bitsobrits » Tue Dec 29, 2020 10:43 pm

Adjustable bushings on a front suspension work fine, as toe is adjusted via the steering arms and caster via spacers inline with the bushings. Camber is set by adjusting each bushing equally, as you want both front and rear arms of a symmetrical A arm (as used on the front of Elans) to be equal length so the bushings centerlines are in-line, and no issues or binding.

On the rear, however, if the two inner adjustable bushings are not set to zero toe, then the two bushing centerlines will be parallel, but not in-line. So if you are running a reasonable toe in, you can install one pivot bolt, but the other is nigh on impossible because the other bushing centerline is no longer parallel nor in-line with the holes in the chassis. If you do manage to get both bolts in, both front and rear bushings are now torsionally distorted when viewed from above (or below).

I run my rear alignment at 1/8" toe in per side, which is 2.5 turns of the 1/2" fine thread adjusters-too far to allow to allow me to insert the second bolt. I was trying this with urethane bushings btw. There may be more 'give' in the stock rubber type, but that still doesn't make the geometry of the bushes 'right'.
Steve

Elan S1 1963-Bourne bodied
Elan S3 1967 FHC pre airflow

Formerly:
Elan S1 1964
Elan S3 1966 FHC pre airflow
Elan S3 1967 FHC airflow
Elan S4 1969 FHC
Europa S2 1970
Esprit S2 1979
bitsobrits
Third Gear
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Posts: 420
Joined: 27 Apr 2011
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