My provisional design

I am sure that this design will change as the project progresses, hopefully based on comments from previous, more experienced builders.

Design principles:

• Rideability
• Ease of welding / alignment
• Mechanical simplicity
• Low weight

I will use rectangular section steel tubing and steel plate.

• Front part:  30x10x1.5,   40x20x1.5,  40x40x1.5
• Rear part:  40x20x1.5
• Pivot:  Steel plate with two Heim joints.

The wheels will be 20 inch (406) with rims for 50mm (Big Apple) tyres.

The rear hub will be a Sturmey Archer X-SD tricycle drum brake hub, allowing the rear part to be single-sided.

The drive will be a conventional derailleur system, initially with a Flevo bottom bracket for adjustability.