Sadly not much progress so far - been busy with VV and had a bit of a lack of space for dismantling it!

Have managed to draw up a draft design for new seat clamps - idea is that a 9mm bolt (will probably machine from stainless) goes through the hole in the top block, clamping the seat itself and the sheet metal 'loop' which goes around the main frame tube. Tightening the bolt which goes through the wedges will tighten it all up against the frame. The dowels between top and bottom parts keep it all aligned - not sure they're strictly necessary.

Not completely decided re materials - possibly aluminium for top and bottom and stainless for the wedges. Or stainless top and bottom (maybe machined away a bit more to save weight) and brass for the wedges. Bolt will be stainless or possibly titanium if I can find it :-)

The original seat clamps were missing when I got it back - they were a bit of an awkward design anyway and never worked really well.





Any thoughts? Peter B, any chance of a close-up of your seat clamps? They may have done an updated design at some point which it may make sense to copy instead...

Peter:

Here is a diagram from Robert Mackinnon's Zenit owner's manual:



The lower 'ramp' wedge is plastic and stationary. The angled block rides the lower wedge as the pin is tightenened.

I don't have any closeup photos of my own at present, but may be able to get some together soon if you'd like.

I agree that the original seat clamps were a rather poor design... especially given the sophistication of the rest of the trike. I've replaced the quick release pins with 'honest' 6mm bolts, and rather crudely shimmed the seat clamps to keep the seat from sliding out of place... for now. It's not the best solution, by any means.

I would encourage you toward the clamp redesign. What you have looks good (to my untrained eye), but I might make the bottom block out of a nylon-like plastic, to save marring the paint. Lining the inner clamp surfaces with some sort of plastic shell might help avoid scraping paint on seat adjustment as well (have already scarred mine). Also, I think you'll want a spacer between the seat mounting 'eyes' to keep them from breaking when tightening the seat bolt.

(I'm aware there's no paint at present to be concerned about, but...)

I'm not all that happy with the seat itself, despite added padding. The seating position just doesn't feel that 'secure', and I may end up trying to find an alternate seat and modify it to fit the Zenit.

(Heresy.)

Peter B.

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Hi Peter,

Thanks for the diagram - yup, that's the design mine used originally. No need for photos if yours is like that too.

Good point re the scratching - I was thinking of a layer of rubber on the bottom anyway.

Re the spacer - the top block of my new design fits closely between the 'eyes' so no extra spacer is needed. That was one of the design objectives - I wanted something which would clamp the whole lot solid with a separate mechanism for the 'lift' action which wedges it in place on the frame tube.

Not a bad idea to add a more comfortable seat - though I don't recall being uncomfortable on mine (can't remember what sort of seat cushion it had when i owned it before). You could maybe incorporate some seat angle adjustment too... and a luggage rack?

Getting some freezing mornings here with icy roads - I'm wishing I had my trike working!

peter Wrote:
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> Getting some freezing mornings here with icy roads
> - I'm wishing I had my trike working!

Here we have over a foot of snow... and I'm not inclined to try the Zenit under said conditions...

Spring is only about five months away... (sigh).

Peter B.

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