Modified Rear Suspension on the Baby Elan

Elan Discussions
1

I would be interested to hear the setups owners are using, after changing their rear suspension to narrow springs, adjustable platforms and 5 inch tyres on knock-on hubs.

In my case I chose TTR’s fast road kit, which gave me Gaz dampers and 14 inch 100lb rated springs. I also changed all bushes for TTR’s uprated versions.

I found problems almost immediately.

I couldn’t lower the rear enough. Even with the lower platform almost resting on the brake disk, the car was at the standard rideheight and I had visibly noticeable positive camber.

After only a few 100 miles the springs had bedded sufficiently enough for the geometry to change, such that the inside of the Minilite rim began to rub on the heads/washers of the outer wishbone joints. This was resolved by the careful use of a grinder on the nuts/bolts/washers, just a little at a time, then a dab of paint and a trip up the road to test.

This seems fine now, but the wheel bearings are new at the moment !!

However, this still left the rideheight and camber issues.

I decided to change the springs to 100lb 12 inch. Instant result. Set the rideheight to about 140mm, and put some miles on the car.

Further bedding in needed to occur. After a while a different noise appeared. This was a rubbing sort of noise. Turns out the tyres were now rubbing on the inside of the wheelarch. Fortunately, the fibreglass was pretty thick at the place in question, and further careful use of the grinder seems to have resolved the problem.

The rear Michelin XAS’s are at about 27 psi, and the current rideheight is about 135mm.

I haven’t measured camber yet, but it is visually negative (just). Am continuing to put mileage on the car (when weather allows), and hope to arrive at some final settings in the Spring.

Regards,
Stuart.

2

Stuart

Not clear to me how suspension movement or bedding can affect the clearance between outer lower A frame bolts and inner wheel rim. They are always very close, particularly with alloy wheels. If outer a frame bushes are not central then it will push one or other bolt heads closer to the rim and of course move the wheel centerline back or forwards. If your problem was only on one bolt each side then I suggest you check this.

Stu

3

On reading my post again, it suddenly struck me that it might seem I was having a pop at TTR as the cause of the problems.

That is not the case. I have bought all my uprated/racing stuff from TTR, and am more than happy with quality and price.

I should add that their Gaz dampers are purpose-made to their design, using Gaz inserts. The units have custom seals, special valving and oil.
The units are individually calibrated and then sold as matched pairs. I chose this route via TTR, to ensure a match. Yes it might have been a bit cheaper buying the bits individually from several sources, but this way I was sure to get the balance right for only a modest extra amount.

Stu,

I was thinking the same about the movement, but couldn’t think of any alternative. Sure when all bolted together first time, it really was minimal clearance between inner wishbone and the alloy rim. But there was no contact initially. Some miles later (not many) the rubbing started. So something must have moved.

The fact that the springs settled is to be expected. They all do, except perhaps racing springs. The fact that the tyres foul the wheelarch was always a distinct possibility. It is well known that 5 inch rims are right on the clearance limits for the baby elan. I thought it was worth a try. Mind you, I did check that the body was square on the chassis, first. Changing the springs to lower the rear was a personal preference, and cheap enough to do. I’ve still the longer new springs to resell, as well.

I’m also happy with the stiffness adjustment on both front and rear sets.
Yes it is just a little stiffer, even on the softest setting (mind you, the springs are new, and will soften with time). Mine are set to TTR’s recommendations for the time being.

Regards,
Stuart.

4

Stuart,

re the wheel clearance. I think (pretty sure) it is the forward and aft’ movement of the car under braking and power that flexes the whole chapman strut through the bushes betwwen the metal bone area. Hence you have varying clearance based upon the how much vigour is applied when driving. I had a plus two (one of two I have owned) about 8 years ago that gave a nasty squeal as I gave it a bit of grief though an Island. Investigation at the road side revealed the outer rear bushes were shot and the strut was moving on the clearnce beltween the ally and the bone and the bolt head was ragging the ally wheel something shocking . Caused by my vigour. In my recent filing that is why I took it out a few times and built up the grief to make the wheel flex for’ and aft’ to see if I marked the paint on the wheel under some load. If you look at the crush tubes on standard rubber bushes they stick out about 2- 3 mm each side. So the potential on shot rubber ones is for the strut to float about 6 mm. If the strut was filed to clean up damaged ally, as is the case on some, it could be more. Hence the late Mick Miller’s attempt at the top hat section Poly ones. He was trying to limit movement in this area. I think he has, but under extremes even the top hat section crushes some what between the washer and the bone. I love my Lotus, but hate this area. Roll on track day car and my fully metal ajustable kit. Hard as hell but not flexing.

Mike (I must get a out more) :wink:

5

I also have a complete TTR set up on my S4. So far I found that these settings work:

Tyres 24psi road / 29psi track
Front dampers fully soft
Rear dampers one complete turn up from full soft.

Still messing with the ride height but so far I am pretty happy when the wishbones are horizontal.