Talk Morgan Forums Morgan Sports Cars Classic Morgans (pre-CX) Double Wishbone IFS for Classic Morgan's

Official release is in April this year for the SUPLEX 'Front Suspension Refinement System' rising rate spring system and tuned Bilsteins. I believe that 'Melvyn Rutter', 'Williams Sports Cars',' Mike & Ben Duncan' and Kev Vernon at 'Tudor Motors' will all supply & fit now before formal release. All have driven a test car. Contact your nearest or favourite from the above to discuss the system and decide.
Once released all Morgan dealers and specialists will be informed.
I have a test car, so contact me off group if you wish.
Thanks for your interest and patience! PJB.

PS I hope this is not considered over the top in advertising on this excellent forum, but this is for the benefit of so many Morgan owners, my test driving job is done. Press adverts will be around soon of course but we are waiting for MMC approval.

Can't wait to get mine Peter. Everything I read and hear on this subject makes it sound like a very valid solution at a reasonable price.

Any clever ideas in the pipeline for the rear suspension?

PJB -- PM sent

Clever ideas for rear suspension? oh yes, with the same philosophy by making the most of the standard car just optimising spring and damper characteristics to give good ride and handling with minimising spring wind up. PJB

Just heard feedback from a trial installation on a 3.9 Plus 8 of the new SUPLEX rising rate springs and Bilsteins. Better ride, less roll, no bobbing nose, no crashing over bumps. Owner pleased.
So fitment to a V6 Roadster should work equally well!
Regards PJB.

The kit will fit and work well on all models from 1952 (+4) to present day (with damper blade or thrust race). The spring & damper rates have been optimised and tested on a range of car weights; from the lightest test car a 1980's 4/4 up to a 950kg 3.9 +8, so will also work well on the Roadster.
There is a spacer and a threaded shroud to retain original ride height and to achieve correct rebound spring interaction for the different weights of cars. Trust this helps. PJB.

Nice to hear something positive about Morgan suspension. The problem with fitting a modern suspension is that suspension systems don’t work in isolation so lets consider other things; like the chassis. The received wisdom of sports car design says that you need an absolutely ridged platform in order for the suspension to do its job properly. Hence cars that have, or had chassis have monolithic ridged chassis. But a traditional Morgan doesn’t work like this. The chassis has the torsional rigidity of a banana and, Morgan would I think maintain that accepting chassis flexing solves the problem of how to make a light car in an economical and simple way. They believe, or used to believe, that their suspension and a bongy chassis somehow compliment each other and work to together. Which they sort of do but its not the way anyone else does it and that’s my point. So I’m not sure what happens when you put a suspension, which assumes a rock solid platform into a car that is anything but ridged. Or whether the same theoretical suspension dynamics even apply since the flimsy chassis is always going to be acting in torsion.

So if you change the suspension design do you then have to start bolting other bits onto the chassis to try to create a more ridged platform? The thing gets heavier, more complicated and where do stop? You loose the clarity and simplicity of the original idea and you end up with, well …just a different car.So if you want a traditional coach built body on a rudimentary chassis you are probably going to have to put up with things more or less the way they are. Which brings me back to my original point which was to question why sliding pillars don’t work as well as lever based systems because I am still not convinced that its purely a problem with the geometry.

Good thoughts Raf. The new SUPLEX (current Morgan supplier)front suspension initial rate(around 100 lb/inch)is about a third the static corner stiffness of the car (Chassis and Body - depends on year etc), as opposed to those older cars still running with a compressed rebound spring where the suspension is indeed maybe 2 or 3 times stiffer than the car's corner stiffness. Now that is an enourmouse improvement.

There is no need to "start bolting other bits onto the chassis" to make it stiffer, it has just enough stiffness and mass to work with the softer initial spring rate.
Also remember that although the torsional stiffness of the chassis is very low, the bending stiffness is not that bad in comparison, and this also resists the suspension bump loads.
Also when the suspension hits a bump it is not just the chassis stiffness that resists, it is also the mass above the suspension with its inertia, eg engine.

It is an exageration of course that a car chassis has to be rigid (impossible anyway of course), anything more than a factor of 10:1 (chassis stiffness : suspension bump rate) starts to be just about acceptable on a low performance car with soft suspension (bit subjective that I know), but OK much above 100:1 for higher performance cars is far more usual and required. But bear in mind this ratio is more than just getting the suspension to work, there are other important reasons for getting chassis/body stiffness high. Damper loads for example, the significant rising spring rate of the new front suspension reduces the shock load into the chassis so that a softer damper bump rate can be used that in turn does not need such a stiff chassis to work. Then there is also a need to minimise secondary ride (NVH) such as you feel after a bump, that needs a stiff structure too.

In the last decade Morgan have gone away from a compressed rebound spring at static ride height that made the front suspension stiffer than the car, all the models now run (or should run) a front suspension with the rebound spring uncompressed so that the suspension on all current cars is actually less stiff than the car.

SUPLEX have not developed the system with "theoretical suspension dynamics" they have worked on this for over two years and thousands of miles of testing different rising rate characteristics and damper curves on different Morgan models.

There is no need to "to put up with things more or less the way they are", optimised rising rate springs and specially tuned/matched dampers offer an massive improvement. Just ask the dealers who have driven the test car.
https://sites.google.com/site/morganatica/suspension/springs-progressive-rising-rate

Sorry if this seems a bit blunt when Raf offers good thoughts on the chassis/body contribution.

Spring is just around the corner! PJB

Which Corner???? At the moment we seem to have a decreasing spring moving back into winter!!! Hopefully the advent of your rising rate spring will improve temperature too!!!

Robbie oh very funny! PJB