A Progression of Ideas a FWD Lean Steered Trike

 It began as one thing and ended up another. The age old challenge of building a rear wheel steered bike provoked me to start on an uncharted path. My original proposal consisted of a short wheel base recumbent design with under the seat steering to the rear wheel and power transmitted to the front wheel.

After reading of the many attempts by universities to build such bikes it became clear that balance and steering set up uncomplimentary forces which promptly dismount you. I abandoned this project after almost completing the frame.

Back to the computer [another diversion learning a CAD program]. After pondering many bike configurations I settled on a front wheel drive (FWD) trike with the cranksets geared and centred in the front wheel.

I didn't want rear steering with it's above mentioned habits, plus the fact that to avoid objects your wheels must first head off in the direction of the very thing you wish to avoid. Tempting disaster hey?

 Problem 1: Gearing

The wheel centre gearing is a good idea, but creates too many headaches. I opted for a more conventional derailleur setup. Power is transmitted along the right side of the trike via the chainwheel to the derailleur, across the double sided track hub to the left side chain, which then drives a fixed hub sprocket on the front wheel.

Freewheeling is by way of the gear cluster; however the left chain is always moving when the wheel is rotating. The front axle locates 4 bearings, locates hub and pedal arms and supports frame.

 Problem 2: Steering

When cornering on a bike, you turn the handle bars; slightly and lean a lot, varying with the speed and road camber. Ideally if I could combine these two angles into a compound angled plane I would have steering. Eureka!

By drawing a vertical plane rearward from the front wheel intersecting it with a compound plane originating from the ground point of the front wheel this then creates the hinge line on which the trike turns.

The front wheel leans and turns and you must do the same when pedalling. The seat is also on this frame unit. The second frame is pivoted behind the seat and just behind the derailleur. It also comprises the two rear wheels and a fixed handle bar unit.

Good points                                                                       

Room for touring luggage on rear frame.

Mounting low, it would possibly make for improved stability.

Easily mounted and dismounted.

Seated at eye level with car drivers.

Shorter and almost as narrow as a bike

 Shortcomings

Front wheel can spin on steep hills and wet roads.

Standard brakes can lock up rear wheels causing instability.

Begins to be unstable at speeds above 15kmh

Although the trike didn't set the world on fire it does turn a few

heads and still poses a few questions.

It is affected by road cambers of 6 degrees or more, wanting to climb up them.

Specifications                                            Maximum steering setup angles                 Back