[sheepdog 44]

I've seen the fifth e-wheel made for the Insight. It's a really simple motorcycle type chain drive with an actuator or hydraulic pump that lowers it and presses it into the ground. That part is key, It needs to have force applied pushing it into the ground for traction and power. The prototype was mounted just to the left of the rear right wheel attached to where the spare tire well is. That is the best place to put it, simple and efficient.

Another problem with mounting it on the tail is you have inconsistent traction on the wheel as it goes over wavy hills and dips. An EV trailer type trailing arm would work, but it's better right next to the rear wheel. Best to keep them seperate.

The problem with a fifth wheel is that the prototype doesn't have the power required for freeway speed cruising. It's more accelerating from a stop and cruising around 35mph. Thats ok for some people, but if you want a serious EV mode plug in hybrid type deal, Then do a partial EV rear wheel conversion. Get some good motors.

If you just want a fifth wheel, from what i saw it looked easy to fabricate if you can weld and all that stuff.