Re: I also ride Moultons
one-eyed_jim":u3vvzpsx said:
GrahamJohnWallace":u3vvzpsx said:
I've got a 1986 AM7, and a 1992 Pashley built APB.
There are a few obvious parallels between Moultons and Clelands of course (and I'm not just thinking about the head tube length!
)
Here is a concept drawing for a Cleland/Moulton/Pederson/ re-invent the wheel suspension system. It dates from 1993 and is based on Newton’s laws of motion and the physics were tested through experiments with radio controlled models. It was never built.
Would it work? Well, yes and no.
With a few tweaks of its proportions, it would achieve what I set out to do. Namely to design a suspension system in which the various rotational forces and reaction forces were held in equilibrium and other forces like chain tension, were isolated. I worked out that it would also need RockShock SID type pre-loadable springs (not available at the time).
On the other hand, the geometry is a disaster. Braking forces are not isolated from the suspension and the bike could stall suddenly if the rear wheel hit a large bump when travelling at low speeds. The cost of making a prototype, and my understanding of its flaws, were the main reasons why it was never built. (Look up Klien Manta, for information on the issues with high pivot suspension designs)
Notice that it does not have a Cleland riding position. This is because moving the centre of gravity, back and up, increases the vertical components of the propulsion forces, which would further exacerbate the design problems.
Unlike the Giant NRS system in which equilibrium is maintained through chain tension + pre-loaded springs, this idea uses the torque reaction from the rear wheel. This was not a new idea at the time. I remember that Joe Breeze used this in his "Sweet-spot" designs.
Yes, it has two chains, one running inside the seat stay. The gearing is based on the "Osgear" derailleur system and is designed change gear whether forward or back-pedalling. The entire drive system is designed to be totally enclosed.
Unlike Geoff Apps who turns his ideas into real machines that work, I just think up I ideas, lots of them. I might even post some more if anyone’s interested.