In Australia vehicle design is goverened by the Australian Design Rules (ADRs). These rules define vehicle types and the design limitaions for each of the vehicle types. Building a car, for example, requires engine emmission standards, seat/belt standards, braking standards etc that must be met in order for vehicles to be registered and on the road.
I have always wanted to design and build my own vehicle but the costs associated with meeting the ADRs mean that designing and building a car of my own design is a lengthy and costly affair. After building the Clubman, the thought of spending the next 3-5 years building another car was a bit daunting, so I've been looking at some other options.
Having ridden motorcycles for many years when younger, I've often considered building a trike, or three wheeler, as the design challenges and possibilities are still very much untouched and the potential for developing a totally new vehicle is still very possible.
Given this idea I looked into the ADRs and found that, not only are there design criteria for three wheelers but that they are similar to motorcycles and hence free of the limitations of engine emmissions and other costly limitations.
I have spent the last year or so sketching ideas and designs for a three wheeler, free from preconceptions of what a vehicle should look like.
I started with a 1Front 2Rear configuration but the dreaded ADRs meant that this would ultimately require many of the restrictions applied to cars. I then developed a design using a 2Front 1Rear configuration based loosely on a motor cycle. This design used handlebars and motor cycle controls and a motor cycle seat but didn't lean around corners like a bike, it rolled outwards more like a car. I didn't like the idea of a motorcycle that leaned outwards as this would feel all wrong, so it was back to the drawing board!
The next phase was to build some lean into it. The internet is a wonderful place for inspiration and the tilting group on Yahoo has been a wonderful source of inspiration and research material. I have now spent quite some time trying to understand how bicycles actually work and the joys of countersteering!
Typically these guys are interested in vehicles where all three wheel tilt and I looked into this with my design too, but the limitation of finding or making front wheels and hubs/spindles meant that leaning the two front wheels was going to be difficult, given my limited resources and budget. Another design limitation I've given myself is to use existing parts wherever possible to reduce the costs and to allow over the counter spares to be used.
Given this, the three wheel tilting option was not going to be possible and so I've settled for a 2F1T configuration, meaning 2 Front wheels (non tilting) and 1Rear wheel tilting.
Fortunately, my 2F1R design was quite easily adaptable to a 2F1T design once I overcame a few design 'challenges' like leaning and steering!! I initially looked at using a single 'chassis' or frame that when leaned over allowed the front wheels to remain upright, but ultimately I couldn't find a front suspension design that would allow this without other adverse effects, so I came to the point where I am now using two frames with a pivot joint.
The front subframe is small, light and contains the front suspension and steering. The rear subframe contains the engine, rider and drivetrain and it leans, like a motorbike, in relation to the the front subframe.
The relationship between the two subframes is obviously very important and will be discussed in a later update.