I have been toying with the idea of putting my 5-1/2 HP Chinese industrial back to work. I have an industrial split pulley designed to change ratios as it slides back and forth. Servicycle and Simplex used a rocker peddle like an early Indian or Hawg clutch to change ratio. I have just about given up on the Sturmey -Archer hub tranny I used as a jackshaft on my 6-1/2 HP one. It just doesn't want to give all 3 speeds and the gear positions seem to drift around. It is generally rideable and will churn out mid-50's and it even stops now that I went to a motorcycle front wheel with a go-kart disk caliper on it. Also the Cerianni fork makes for fewer warts. I think the VST would make life more pleasant. Not really motivated to do it now what with having to title,tag, insure it and just don't give a hoot for the tiddlers. What I have in mind may stretch too far aft to be practical There is also the possibility of running 2 Gilmer belts with both driven cogs freely rotating on the shaft to the final drive. A hollow shaft with a rod and enlarged place to push balls into half-holes in the cogs. That is how a Hodaka tranny works. Without being in an oil case, lubrication could be a problem. Maybe aluminum bronze or likesuch?