As you know I love recumbent trikes. They are a blast to ride, comfortable and safe. They also have the potential for amazing speed (particularly with gravity assist).
But they have disadvantages too. That is one reason we all need to follow Richard Ballentines advice and have more than one bike.
Anyway three very different trike ideas have caught my eye this week.
First, the 2006 Trice Standard Models from ICE. I have linked to these before but mention them again as the current state of the art in tadpole trike design. You can’t go wrong with one of these. The team really know what they are doing. Plus of course for us Brits this is one of the few opportunities to buy a local product (although I suspect the foreign parts count rises with every new Trice model).
Second, the Shortbike. I found this in Velo Vision (which has much better photos in issue 20 than on the manufacturers website). This is not high performance (and the riding position looks like you end up a bit odd with both legs and arms stuck out in front). But the idea is great: sealed drive, bends in the middle via handlebars and good carrying capacity at the back. I would think that for a pop to the school or shops machine it could be great.
Third are some pictures from Ian Sims of Greenspeed of a Front Wheel Drive, Rear Wheel Steer trike that they produced for a primary school to race (he writes of reaching 78 kmph). It makes me wonder if this might be the basis for a fast low maintenance trike.
If the front wheel drive used a Rohloff then the chain could easily be fully enclosed and thus last for ever. If the drive could be to both front wheels then traction and tracking would be great. The rear could easily detach for folding (no chain to worry about). Different rears could easily be connected for load carrying etc. The front wheels will be easy to fit superb mudguards to (with full side protection) making this a great winter trike. Oh and it could easily be very low indeed (no chain going under the seat) for stability and aerodynamics.
Getting the steering right will be tricky (I guess that building a development rear with everything adjustable would be essential). But the wonderful stuff about the Dymaxion car would provide some info.
If you go for 2 wheel drive at the front then either you keep it really simple and just direct drive both and ignore scrub (could get you through tyres really quickly). Or you add a freewheel in each hub (that means you are always driving just the inner wheel when cornering which might work well with rear steering by helping straight line stability). Or you have a differential (poor for cost, weight, efficiency) but will be best when turning lots of tight turns as you don’t just drive the inside wheel (which is a problem on really tight turns as it will hardly move at all).
One wheel drive will be ok as long as it is the inside wheel (drives you up the crown of the road) until you try to climb a steep hill in the wet or when there is ice about when you are going to go nowhere. For race track use it is probably optimal for weight saving (although then it would be best to be the outside wheel).