Button, as per my explanation the 5L does not need an 'anti sway bar'/'anti roll bar'. These [IMHO] nasty devices add to single wheel stiffness and maintain stiffness with both wheels in phase. This is the opposite of what is required, for ride one wants compliant single wheel responses but then find a way of adding roll stiffness without increasing single wheel stiffness. The links in the 5L are arranged so that in roll they start to 'fight' or 'lock up' thus increasing roll stiffness with the rate of roll stiffness increase controlled by the rubber bushes - this is done without stiffening the small displacements of single wheel inputs. So this gives good ride over road irregularities BUT with significant anti-roll from the geometry of the links. Look at the work done by various car manufacturers now (BMW Mercedes etc) to reduce the stiffness of anti-roll bars and build in anti-roll with rebound spring control to improve ride. Good to hear from you Bill - Regards Peter.
CBY. At your request, I add the following images to show the design at the risk of appearing to market the product. I declare that I am involved commercially in this product but at heart I love Morgans. Moderators - If I have abused the rules of this forum please tell me. Regards Peter.
The kinematic of the rear axle seems to be close to a circle whose center is the rear axle of the previous leaf spring with little variations of the wheelbase.
It looks like the Earles suspension of the old BMW motorcycle. When you brake is there a lift movement?
CBY, there is no lift under braking and only a little squat under power. Very little wheelbase change in bump as you say. The pitch centre does move around a bit in bump, tough as the top link articulates a bit. Had to compromise somewhere to get the geometric progressive roll stiffness right - space as always is a bit tight. Thanks for your comments. Peter.
Hello PJB, For my understanding, the clevis fixed on the rear axle have a slotted hole where are bolt the black links with rubber bushes. Does the bolt slide in the slotted hole or is it only for adjustement and in this case the rubber bushes compensate the length variation when the rear axle move up or down?
What you are seeing in the photo that may seem to be a slotted hole is, in fact, a second set of holes. There is plenty of metal between the two sets of holes, don't worry.
The rearmost holes are used in the case of the earlier models of Morgan that have part of the handbrake mechanism on the back of the diff. In that case the axle has to be mounted aproximately 20mm (3/4") further forward to avoid impact of the mechanism on the fuel tank. This would be the same position as with the leaf springs. Taking accurate measurements before you start is part of the installation proceedure.
The car in the photo is a relatively late model car that uses a cable machanism and the axle can be mounted in the rearward position. This centres the wheel better in the wheel arch which is more aesthetically pleasing.
There is also another variation which can be ordered. This has a narrower cross bar for the older narrow chassis cars.
The system works, but I try to understand how. My question is about the cinematik of the upper black link.
My understanding : the lower tubular bar between the previous leaf spring axle and the rear axle and the upper " black " link are not is the same plan and the layout is not a parallelogram. When the rear axle moves up or down, the center distance of the bolts’axe of the " black " upper link varies and is compensated by the deformation of the rubber bushes. The deformation of the rubber bushes brings stiffness, like an additional spring, in order to stabilize the rear axle in all directions. I don’t know if I am right.
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