1. S&S coupled custom welded frame enables transport in two pieces so one is not bench pressing 86# of 8'3" long bike at a go into truck bed or atop truck cap. A godsend. Couplers on all cables as well.
2. Foot-forward frame (custom welded) reduces stress geometry on knees. When I try my single normal bike the knee pain is startling and disabling.
3. Retrofitting with Bafang 1500watt mid-drive motor and 52v battery. Had to rebuild all systems and machine some parts, to accommodate. Throttle-only assist up hills, soft ground, and windy conditions.
4. Freewheeling chainring adapter spider from Sick Bike Parts. Captain and Stoker can pedal or stop independently. Easy stops and starts, no surprise if goose motor on hazard.
5. Drilled out rims for Schrader, ditched the Presta valves. More robust, no more bent stems and easier to get tubes or assistance on trail if ever needed.