Talk Morgan Forums Morgan Sports Cars Maintenance & Servicing The Trad Supension Basic

Yes CBY, I understood that. But it is quite an assumption for real life and I wanted that to be clear. And the newer aftermarket, when using coil springs, do not reveal their spring rates as the older aftermarket and the Factory once did.


Yes. Then you can draw conclusions. But they would not apply to trads that do not use girders or have a stiff chassis like all modern fare. They use a light flexing frame, typical of the Golden Age of Automobiles in the 1920s and 30s. . The flex is part of the suspension and imparts a delicious feel when set up properly. Something I have never experienced in other autos. And a dual point spring system is best as it spreads the stress over two points on each side rather than focusing them on two. The problem of focusing suspension or other forces always causes problems to Morgan trads. Even the mighty crossframe at the front bends like a bow with braking forces For decades, moggers banged thee old kingpins down the tubes to prevent that. https://www.gomog.com/allmorgan/CrossframeBrakingEffect.jpg When the Factory tried to copy the Mulberry anti-tramp bars to cure early Roadster tramp, (they used one anti-tramp bar only to keep costs down) their fitting point sheared!. I could go on with examples forever. Leafs springs (bless'em) work for decades on the Morgan trad chassis. They also USE the flexing frame rather than ignoring it.




Absolutely. Not a "today car" at all. Applying standard suspension principles that have been used and taught for the last 50 years is inherently unwise. However, I do understand that experts taught in ways and means of another era, think they are designing properly. A good question to you would be to ask yourself why leaf springs are the goto technology in the long distance tricking arena. [b]Think of a standard 36m trailer for example. What does it share with a trad Morgan?[/b] They certainly do NOT have a stiff frame. Ever seen one that went off the road?

You mean like my UK chassis below?



Morgan trad chassis are not made of memory steel or anything better than simple mild steel railing. Material cost is about 400 quid. In the case you describe, they will bend and stay that way. But they will still remain flexible. It is why I advise anyone making or buying a chassis (aside from G.E.E.) to ship their chassis directly to a chassis straightener shop, and spend a few quid to have it straightened. But it is going to change anyway depending on equipment and usage. But it will make assembly a lot less frustrating. I deal with this daily on the Help Line.



[quote=CBY] Some years ago I modelized the chassis of my PLUS 4, I was curious to verify the MORGAN chassis legend. I am a normal driver, not a pilot and I like sciences, so I use stress analysis program, this is less dangerous than extreme driving and keeps exercising my mind. Stress analysis on the main girder gives an idea of the constraint values. The most critical part begins at motor & door level. Under a 3g vertical impact the constraint is roughly 12 daN/mm² (~3,82*3) inducing a security coefficient of roughly 3 (depending on the used steel).

I come from a non-mechanical background as well. From a more cerebral training and profession. I prefer Morgans. They have been my hobby for 30 years, either working on them or mogging in them. I retired very young and have studied and experienced Morgans more than all scholastic studies. I was soon assured by everyone working on them, that each one is different, for the reasons I have given and other stuff. Accordingly, I don't think Morgans are susceptible to formulas, especially another technological era based on stiff chassis era. Hell, that era even reduced the automobile tyre air cushions. Not everything, in any era, makes sense. One has to progress by trial and error.

[quote=CBY]I love my MOG, and use it for touring, with speed limitations you can keep driving sensations we can all share, but each with his own methods. Experience is the final complement of the theory.

Me too. I muse now about the last 25 years whether Morgans and the aftermarket has changed so much because the newer decision makers were trained to expect a one-size-fits-all car. Stiff chassis, like the Aeros and the CX cars.. They cannot not fathom a flexing chassis. (who can blame them?!!) People from Aston Martin or Ferrari or those who read modern car magazines worship stiff chassis. But any trad owner will tell you how he/she adores the feeling of his trad when it is set right, and on the right road. My wife wouldn't let me sell it even if I wanted to. I have agreed with that on the condition that HW + Battery<MW

I do not apply this thinking to the non-Morgan components trads use. In my case, I choose what is best from the buffet available for my, for example, engine. 1960 to 2004 and the aftermarket.

Thank you for the link. It seems to show the advisability of leaf springs on trads.

Lorne