Talk Morgan Forums Morgan Sports Cars Maintenance & Servicing Rebound spring gap ??

Thank you CBY.

My wife is also happy with the result

We use the Morgan quite often for touring with luggage so ground clearance can be critical, hence the 195/65 R15 tyres.

Regarding ride height as governed by the front suspension it is fairly easy to understand that if the upper spring is set so that the static ride height is such that the lower spring is just touching the underside of the sliding stub axle it is in fact the length, or position, of the uncompressed and rather rigid lower spring which sets that static postion. If the position of the upper spring is adjustable you can therefore shim under the lower spring and raise the upper adjustable spring seat to lower the car by the thickness of the shims (always keeping to the rule of an uncompressed lower spring).
Because of variations between different models the SSL kit includes 2 x 20mm spacers that are placed as require by the installer (and the car). My installation, as adjusted to my particular requirements, uses 10 mm below and 10 mm above.
If, over time, the upper springs settle a little I can adjust the upper spring seat to once again restore the ride height always to the point where the lower spring is not in compression.
I won't go into full details here but if anyone really wants to know just ask me.

I can well understand that SSL would not sell individual components of the kit (except in the unlikely requirement of spare parts). The system is designed such that it works together as a set. It is a professionally developed, tried and tested, Morgan front suspension improvement system. I have always found SSL to be most approachable and they even supplied me with a slightly higher rate set of springs for the rear coilovers of the 5 link system. This has been a great help with the extra 25 kg of luggage that we carry on the rear rack when touring.

One last thing regarding dampers ( also called shock absorbers if combined with springs). The standard dampers that were supplied by Morgan are not particularly good quality but the did offer better alternatives as an option. It seems that this is an area where there are several very valid alternatives. However I would like to cover the issue of gas-filled dampers.
A gas filled damper is not a pneumatic suspension system, it is still an oil damper system. I will leave the explanation to my-cardictionary.com


I will add to that that a system of valves and apertures (that may be adjustable) governs the flow of oil in compression and rebound. Further reading on the subject at https://corneringperformance.com/how-do-suspension-dampers-work/

Just remember a pogo stick is a suspension system that does not have a damper

I think I will stop here as I do not want to get into a sort of text tennis match. If anyone wants further information feel free to contact me by PM.

You make a good point Peter regarding the unloaded rebound spring in the SSL RS kit defineing the static zero pre-load ideal setting. Misunderstood by some though is that irrespective of the 20mm spacer position, above, below or split in two and either side of stub axle (as yours) the stub axle and it's spacer(s) can be considered collectively as a unit which is always the same length. The main spring pre-load therefore remains the same for any particular model despite the adjustable collar needing to be lower for max ride height choice.

In essence then ride height options within kit do not affect spring loading.

2011 Plus 4 Sport….

Richard, you have already answered my first question which I was about to post in this moment:

You say, „In essence then ride height options within kit do not affect spring loading.“ That is what I thought also.

Peter, you say:
„If the position of the upper spring is adjustable you can therefore shim under the lower spring and raise the upper adjustable spring seat to lower the car by the thickness of the shims (always keeping to the rule of an uncompressed lower spring).“

I thought, the car would be raised in this case in comparison to the wheels?

Your quote from Peter's post sounds correct to me Heinz. The shim could go above or below rebound spring it would make no difference. As long as it was below stub axle it would raise same and therefore lower ride height once compensating adjustment was made to main spring to maintain zero gap with rebound.

I would imagine given the choice the shim or spacer should be above the rebound spring (as in SSL instructions) and so marginally reduce striction between spring and stub axle during turns as the inner wheel becomes unloaded, unless you have lower steering bearings of course, as I have.

The 205/65 R15 (or 205/60 R15) tyres were optional and fitted (normally?) to wider rims. The 205/65 actually give pretty much the same ride height as the narrower tyres fitted to the 4/4. Interestingly this would allow you to use a 4/4 wheel and a "space saver" spare.

About 9 years ago I created a table to compare the different tyres used on a Plus 4. The pdf file can be downloaded at http://www.talkmorgan.com/ubbthreads.php/ubb/download/Number/16690/filename/Tyre%20Sizes.pdf

Yes Richard's answer is correct but perhaps I should have made it clear that the adjuster is above the main spring and raising it effectively releases the spring allowing the car to settle lower. If it is raised too much a gap would open between the rebound spring and the bottom of the stub axle. Naturally, because of the weight of the car, the compression of the spring always remains the same.

Thank you both, Richard and Peter, for your explanations.

So was I. Gambalunga mentions using two tyre sizes on his Plus 4. 195/60 15s and 195/65 15s. I felt that should be absolutely clear. Heinz picked it up right away.

I seem to have offended some people here again.

CBY. It is a small matter the flatten the ends of a cut spring. Any machine shop or well equipped amateur garage can do it. In fact that is what happens to all coil springs including MMC. I am surprised you are unaware of that. I am very impressed with your credentials. I am merely a retired fellow (32 years) with Morgans.

As I noted a few times, I have decided that that a neoprene bumper, progressive, would be a lot smarter than anything suggested to date. I gather you prefer a progressive spring of varying rates and inconsistent strength along its length. Would that mean you would also recommend a bootie to cover it?

I find the whole discussion here basically very instructive and exciting. Let's keep in mind that actually all participants in this thread have understood the principle of the Morgan front axle. That wasn't always the case, by the way. A few years ago there were a few members who didn't want to believe that when pressure is applied by springs on two sides to a point in their center it is the same as a parallel connection of two springs.
How someone achieves his individual optimum of the chassis with the right choice and tuning of the springs corresponds to personal preference. I can fully respect anyone here who has chosen the Peter Ballard front suspension package solution...with all the fine tuning possibilities. I myself just bought 140 pound springs and steering bearings from Peter Mulberry for my little 4/4. The correct length of springs was critical and for many years this setting has worked almost perfectly. The rebound springs only come into play when the car is rebounding or cornering. I haven't had to readjust anything main springs outside of replacing the kingpins either. Maybe because my 4/4 is so lightweight.
Of course, someone may say that 140 pounds of springs is quite a bit for a 4/4. But I feel very comfortable with the controlled firm suspension in the front (which also is compliant enough for my taste) and a slightly more comfortable setup in the rear. By the way, with the lowering blocks removed (plus longer shocks and more clearance for rear suspension deflection) and that's what I learned from your website, Lorne, where you are referring to the 4/4 Sports. My one is not a Sports but a later Sigma model with a spare wheel and a luggage rack…but MMC kept to use the lowering blocks even if the car had added weight again.