Suitable Shockers

[Greylag]

Hello All,

I'm contemplating changing both sets of shockers on Blue the 2CV trike for cosmetic reasons mainly but my other half said she thought it had "bottomed out" on the left hand rear shocker when we were out on it the other day. I've asked a few mates and none seem to be able to agree on which are suitable, the rear ones are set at an angle and are 285mm long the front are 320mm long. I've seen pit bike ones rated at 800lbs and 1000lbs but these are supposedly to fit 150-200cc machines which leaves me a bit sceptical about the claims on strength. I've been told that the angle of the rear shockers will reduce the rigidity by at least 50%. I know that a lot of the kit cars use motorcycle type shockers so I thought I'd seek the opinions of the members on here.

The photos are of the shockers fitted at the present time.

Thanks in advance
Regards
Dave

[Geoff Ryall-Harvey]

I would relocate the brackets and make them much more upright. They just can't work properly at that angle - even if you uprate them.

[billdavies]

Graylag,
I agree with Geoff, it is better to get the action of the rear shocker as near to vertical as possible. However in your case the space frame that carries the engine/box assembly has a limited capacity to extend the top fixing. There appears to be a cross member that could be stretched to increase the angle...but watch the bottom fixing as it is inside the wheel rim...you will NOT be able to get them vertical on the basis of your bottom fixing.
On the front shockers you can play about with different spring ratings...chopper shops are probably the best to advise. They come into the max loading on heavy braking
regards Bill D

[howardjs]

Hi Dave,
Yes the angle of the spring damper unit means that as the suspension compresses the rate of the spring will decrease. If the spring is vertical the opposite is the case.

Looking at the photo of the rear end. it looks as though the coil over unit is the only thing locating the top of the hub upright. I suppose the lower joint at the wishbone to hub must be a substantial horizontal pivot joint. Even so, having only the spring unit as the location and pivot means that the top of the upright is not very well supported for fore and aft movement or hub twisting loads (wind up) under acceleration and braking. It also means that the wheel will get some positive camber angle as the suspension rises. (unless the wheel camber is very negative unloaded) This will tend to reduce the tyre contact patch area when cornering.

I know it means some engineering but I would be inclined to change this arrangement by adding an upper wishbone and relocating the lower end of the spring unit onto the lower wishbone (see photo). The spring would need to offset to avoid the drive shaft, however this would solve all the problems.

Howard

[Greylag]

Thanks for the replies all.

Howard my mate says he can relocate the top mounting to bring the shocker more upright so I'll probably let him have a play with it for me. I'll get some heavy duty shockers for the front they don't seem to be a big problem at all. All the shockers are working but going rusty so it's mainly cosmetics but my other half was convinced it bottomed out on a right hand bend ie left hand shocker hence why I was enquiring about the back shockers.

Thanks again for the replies
Regards
Dave