There are a several ways of achieving a rising rate spring. The one chosen by PJB was to use and inner spring which added to the overall rate as the outer spring became compressed. To look at the relatively light weight inner spring you would not think it does much but it seems to be cleverly calibrated to give just the correct amount of increasing rate.

The other thing to consider is that the correct setting for Morgan front springs leaves the lower rebound spring unloaded (enough so that you can just turn it by hand) at static ride height. Achiving this with the variables involved without an adjustable upper spring seat would seem to me impossible.

Worth mentioning also that the rebound spring should have a fairly high rate to limit the downward travel of the unloaded wheel in cornering. In Morgans this has the effect of reducing body roll in cornering. This is part of design that PJB has used successfully in both the Suplex RS kit and the Suplex race suspension.

I should make the usual disclaimers that I have no interest in Suplex other than being a happy customer but I have been intersted enough in the theory to seek some education on the topic. I am by no means an expert but I do understand at least some of the principles involved (with some help smile )

Peter

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