Trike rear suspension softening possible?

[Broken_Mold]

I sold my last VW-based trike about thirty years ago and have wanted another since. I have had a good collection of Beetles and Beetle parts for even longer. The only thing I lacked was a good frame with which to start. I really wanted this trike, unlike my last, to look more like a motorcycle than the run of the mill VW-based trikes complete with swoopy fiberglass bodies. I had in mind for it to look similar to an early Harley Davidson servi-car. The wide glide five degree triple trees, front fork tubes, and 16" front wheel are from a Harley. The rear wheels are 4 1/2" smoothies with old style hub caps with 5.60-15" Firestones from Coker Tire.

I recently found and bought an old "Boxer" trike frame (with MSO) that was set up for a Honda 750 engine as it looked like it would lend itself well to a VW trike project and still look like a motorcycle. I have the front end mocked up to verify my math calculations for rake and trail as well as to adjust the seat, handlebars, brake, and clutch pedals. I plan to use a '69 Type 1 torsion housing which I don't have cut down yet.

The torsion housing spring plates are the reason for my inquiry. I've adjusted spring plates to correct saggy tailed old Beetles in years past so I know how and why that works. What I'm wondering about though is actually unloading the torsion bars so that the very light weight trike will ride smoother. The only weight on the rear of the trike will be the motor, trans, and solo rider. Has anyone done this before? If so, can you tell me about what degree I should set the spring plates at? Will the axles be approximately a few degrees above horizontal when the spring plates are set correct?

[eyetzr]

You could just ditch the torsion springs all together and use coil overs and a torsion elimination kit. You would have any spring tension you want. Sand rails do this for travel, bugs with air ride do it for airbags. Check Colrydes web site for some images.
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I think he meant "rare", as in "not well-done"

[Broken_Mold]

Since the torsion housing will be either a '69 or '72 I actually had considered the torsion elimination option. However, I knew that coil-over shocks designed for off-road applications were not only very expensive but the spring tension and rate were overkill. Cheaper coil-over shocks (like Empis) always advertise not to use them alone but as "helpers" to assist stock suspension.
Since my trike application doesn't have the weight of a factory steel body or even the weight of a fiberglass body I'm left wondering if the cheaper coil-overs might work. The coil springs on them seem to be about the same as the coil springs on rear shocks on some larger bikes. I had even considered bike shocks but thought that finding one with the correct mounting holes on both ends and the correct length might be quite difficult, if not impossible.

[eyetzr]

You need to shop in the hot rod section. Try Summit or..... spring rate based on vehicle weight.
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I think he meant "rare", as in "not well-done"

[ratrog]

I'm on my 3rd trike as I write this. I always just lower the rear end just one outer tooth on the torsion bar and use cheap oil filled shocks. Give a soft comfortable ride and because its still light you don't get excessive rear camber.