Talk Morgan Forums Morgan Sports Cars Classic Morgans (pre-CX) New Trad suspension set up

Hi Tim

That's how we set up Andy's initially but due to ride height problems (I think speed bumps? Andy?) he was back the week after for more tea and a swap of the spacer, mind you the second time took a fraction of the first time....we were not replacing the kingpins and bushes and everything was clean ;-).

Had mine changed last November. Such an improvement over our rough undulating roads. People who have driven it have been very impressed by the improvement. Remember mine is 1989 vintage that had been fitted with soft springs about 8 years ago.

And this is only the front suspension alteration to cope with dreadful roads , the back is more difficult still as there are little if any options ?

I think it is a little bit of a case of not being able to have "a drunk wife and the barrel full" (The Italian equivalent of not being able to "have your cake and eat it too").

First, I have to say that I believe the case for not having compression between the upper load carrying spring and the lower rebound spring has been fairly well proven.

I refer anyone interested to: https://sites.google.com/site/morganatica/suspension/main-rebound-spring-interation

To get back to the Suplex kit: in order to have a comfortable ride, and rising rate springing, it is obvious that the initial movement is going to be a little softer that the old standard setup. In cornering body roll is reduced by the very rigid lower spring which does not allow the unloaded wheel, the inner wheel, to be pushed down by the force of the upper load carrying spring.

In my experience it works very well. The front suspension works over bumps, in cornering the car feels very stable and well planted, and if bumps are encountered in a corner the front wheels do not tend to skip sideways. The reduction in body roll by comparison to the previous setup was quite marked.

I am no rally driver but I do tend to push fairly hard if I don't have my speed controller in the passenger seat. I do not particular notice a higher initial roll on turn in, I and others who have driven the car think the car feels very well balanced.

When the kit was first installed it was not really set up correctly and I had to make some adjustments. I have checked on a couple of occasions and I have not found the need to make any further adjustments. My setting is such that the lower springs are under very slight pressure but can still be turned, just, by hand. I imagine that if one required to reduce the initial softness to give less initial roll on turn in it would simply be a matter of ordering springs with a slightly higher rate. Comfort would be reduced but it would be more to the liking of those that require a faster turn in.

I did hear some discussions of Suplex developing a competition version but I have no idea if that progressed.

I imagine that much of what has been learned in the development of the Suplex Front suspension ‘Refinement System’ has been applied to the current spring setup on production cars. I would expect to see stiffer and virtually unloaded rebound springs and that would be bound to make an improvement even without the adjustable rising rate system.

There is quite a bit of information here including, at the bottom of the page, the possibility to download both fitting instructions and a quick setup guide. An important note is that the dampers must be removed to correctly find the static ride height and what is not mentioned is the importance of having the car on a perfectly level surface.

At the end it comes down to personal preferences. In other words if you want a comfortable ride, to use the car for long distance touring, without sacrificing good handling, you would probably prefer the Suplex front suspension setup. If like fast and furious, fast steering and no initial roll on turn in, and you are not worried about comfort, something else may suit you better.

Morgan have used an improved system on the SP1 that uses coilovers. Others are currently testing a coilover system, and Mulfab has already developed one.

My feeling is we will hear more on rear suspension in the not too distant future.

What chassis is the SP1 based on? please.

It is a modified trad chassis. There is a thread on the topic of the SP1 rear suspension.

http://www.talkmorgan.com/ubbthreads.php/topics/222263/1

Whenever suspension kits are marketed, the science is a bit sketchy, and nowhere worse than with the MGB upgrades which appeared in the 90's. We had cantlevered telescopics on one side of the wishbone, retaining the unvalved lever arm as a top link, right up to replacement double wishbone with coilovers.
At the rear there were parabolic springs, telescopic conversions, trailing arms with coilovers, and finally the IRS using a Sierra diff in a tubular cradle with rear discs. None were ever presented with empirical data. For those who don't part with money easily, this makes it a hard sell.
In the MGB world there were very few complaints after paying for the upgrades, that's human nature.
But then again, how can 'improvements' be measured to demonstrate anything worthwhile?
How would you measure comfort? How do you measure roadholding and handling, other than times round a track?
And who's to say that I'll like what you like?

In the Morgan world I can say that Mulfab bearings present much lighter steering than with damper blades. The difference is significant. I can also add that Mulfab bearings present lighter steering than MMC steering bearings, and that is why I upgraded Mr Bumble with the kingpin change.
Other than that, all I can say is that I prefer AVO's to standard MMC dampers. You might not, or you might prefer Koni's. I don't like Koni's because I bought an MGB with Koni's on the rear and the ride was terrible (hard).
I like my Morgan to corner flat, so the very idea of initial roll (after paying the money) puts me off, big time.
And so on...........

Good dissertation Peter, thank you for posting

That's very good news ! I hope we will be able to fit it to existing mogs .