It's a tandem, Jim, but not as we know it.
How on earth does having two separate gearing and drive systems work?
Its quite simple really, see the quadem project in the hpv thread for the design, build ,modifications it has gone through on the way .
It started life as a tadpole and became a single seater quad before undergoing a stretch about xmas time
The gearing is easy the right hand gears go down to the back via 4 chain lengths to a 8 speed block with a triple on the front as per any tadpole
but
the stokers drive is on the left and runs down the left hand side to a 7 speed block with 2 and a bit chain lengths . both freewheels are mounted on the rear axle side by side and there are 2 rear mechs as well. Looking from the back it looks rather strange but it does go well with 2 fit bodies . the 4 disc brakes operated via front and rear combined pairs stop 22 stone quite quickly - it does get a lot of attention .
The next stage is to fit a " back pedal front mech " system to allow a triple chainwheel on the stoker but TBH 7 speed on the rear is enough .
The quadem is/was a prototype tandem quad and is almost 9 feet long and a tad under 3 feet wide . weight about 90lbs and has a centre suspension point which gives a little more flex to the chassis to keep the wheels on the ground .
two freewheels , 5 brake cables and 3 gear cables so far !
the cut and shut is just in front of the freewheels 20" was added to go from a single seater to a tandem
