Anybody using sigle piece rear springs?

[David Wicks]

As my 74 GT clearly has rear spring issues, sagging and a list to port, I am reviewing the different replacement options out there.
OK, the straight swop with standard issue leaf springs and retaining the lever arm shockers is the obvious and cheapest route but what about parabolic or single piece springs?
There is quite a bit of feedback on the parabolic set up from various sources but I have not dredged up anything on the single piece springs.
Any experience with these springs out there? Are the ones sold by the MGOC steel or composite? Will they run with standard shocks or are telescopics advisable ? If of composite construction, how durable are they? (I'm thinking delamination issues here)
All contributions welcome and happy new year to everybody

[Ian F]

Hi David,
probably not directly answering your query, but I would recommend getting rear springs of "OE" quality rather than some of the cheaper options available. These should have the interleaves between the metal, perform as per the original design, and be more durable. Having said that I have had a "SPAX" telescopic conversion on my BGT for several decades. Really easy to fine tune the damping with these, and get the set-up to your liking. With my new "OE" spec springs I found the best settings for the SPAX dampers to be around the softest setting available.
All the best for 2017,

IanF.

[David Wicks]

Thanks for that Ian. I fitted Gaz shocks all round to a GT I had over 10 years ago and like you thought they were pretty good but having just completely rebuilt the front suspension and steering of this car I am now a bit "budget driven". From what I have read, Lever Arm shocks are OK for a normal spring but some experts say they can be overwhelmed by a parabolic so I may have to splash out on a couple of Gaz's for the rear if I go that route and find the Lever Arms can't cope.
The MGOC standard springs are quoted as having interleaving so I guess they can be trusted as OE - I have had loads of stuff from them before and I would rate them as an OK supplier.
Still very intrigued by the single piece spring though and hoping that members will have some knowledge or experience of them.

[Ian F]

It seems to me that if the original lever arm dampers are unable to control parabolic springs, then the springs must be quite different in character to the originals and wouldn't that alter the handling significantly? I think I read sometime ago that parabolic springs were recommended for "comfort", so perhaps they are very bouncy and would take quite a bit of controlling!!!

IanF.

[Vic Butler]

Telescopic shock absorbers must be used with parabolic springs. If the springs are known to be of a good quality then there should be no problem.
I fitted 4 to my Land Rover many years ago and have had no problems with them at all. The ride is softer than standard springs but not excessively so and there is no rusting between the leaves.
. Vic Butler

[Vic Butler]

Further to my previous posting I forgot to mention that parabolic springs have a longer travel which lever arms are unable to cope with. I had to fit longer telescopics to my Land Rover which has telescopics as standard.
. Vic Butler.

[Peter Cresswell]

I have heard mixed reports on the use of parabolic springs - some good, some bad. I also know some people who fitted them and then went back to the standard spring because they didn't like the ride characteristics. I guess it all depends on what you do with the car and how you drive it.
This article might help to understand them:
http://www.mginfo.co.uk/upgrades4mgs/Dr ... rings.html

Although I have Spax adjustable telescopics on the rear of my Roadster with standard springs, and they do feel harsh even on quite a soft setting. It might be to do with the rebound characteristics which you can't adjust separately, being out of phase with the spring rate. I'm planning on going back to lever arms with 25% uprated valves and a slightly thicker oil.

[Peter Cresswell]

Re Interleaving.
This is certainly mentioned in early issues of the BMC Workshop Manual for the Mk1 (narrow tunnel and 3 synchro box) along with a note about which leaves the interleaving goes between. Curiously, the interleaving is not mentioned in the section about dismantling the spring and reassembling it! However in later manuals there is no mention of the interleaving at all, so I think it was dropped at around the time the Mk2 and MGC were introduced. In both cases the springs should be lubricated using Shell Ensis 260 Fluid, which appears to be a rustproofing oil similar to POR15
This article describes 'refreshing the rear springs' and the pictures don't show any interleaving.
http://www.mginfo.co.uk/upgrades4mgs/Dr ... rings.html
Can anyone confirm this?

[Graham Wilkins]

I have fitted parabolic springs to my 1966 BGT which had standard, but new, lever arm dampers. The ride was very bouncy so I uprated the lever arms with 25% valves. This has provided a much better, controlled ride and the road holding is very good. Ideally parabolic springs should be fitted along with telescopic shocks in order to control the flexibility of the springs. However, I am of the opinion that the MGB rides better with lever arms all round; so for me the uprated valves was the way to go and I am pleased to say that this does work well.

[David Wicks]

Thanks for all the replies - the consensus seems to be that telescopic shocks are not the holy grail, which ties in with my experience of a few years back. Also it seems, lever arm dampers are more matched to cart springs, sorry leaf springs, particularly if you want to go fast and stiffen the ride with upgraded valves.
As a person in his mid seventies, I don't go very fast these days and comfort is more important than speed and handling. So a set of original spec 7 leaf springs it is I reckon and retaining the original levers with their normal valves and damper oil.
The old girl should then be as she left the showroom, steering and suspension wise, which will be more than OK for me