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09 Nov 2003
p. You know what I would like to see invented? Automatically-engaging stabilising wheels for bicycles. Bikes are fine when you are bowling along at some speed, but you lose the gyroscopic stability as you slow down. Also, when you are riding in traffic, you are continually slowing down, putting your feet down, and engaging your feet on the pedals again--all of which is inefficient. On a recumbent bike, the speed at which instability strikes is lower, and getting the bike started is harder. Tricycles are great in this respect; you can stay with your feet clipped in to the pedals for maximum pedalling efficiency, and there's no problem about stability at low speed. But trikes are big and heavy so you use more energy just shifting the extra weight, and the extra wheel and frame sections make them expensive.
p. In my opinion, the ideal compromise would be a pair of stabilising wheels, which would automatically lower when the speed dropped below a certain level, then raise again as you got back up to speed. Ideally, the speed threshold would be adjustable for different bikes and riders. I have a very simple computer on my bike which measures my speed quite accurately, so the technology already exists for that part. It would also need a small and light motor to raise and lower the wheels, but as they would be lightweight and fairly small it could be a done by a small, battery powered motor.
p. The result would be relaxed, efficient commuting, and increased safety in the event of emergency braking, and the wheels would even form a handy stand when parking the bike. The main sticking point would be how good it looked, though--no-one would want to be seen dead on a bike with training wheels, so they would have to be designed with a hi-tech, sporty look. If anyone feels like building a device like this, I would happily be a beta tester!
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Richard: I've done exactly the same thing with clipless pedals, which is why I haven't fitted them to my recumbent yet. I love your idea for speed induced lift on the wheels -- assuming that I ever get up enough speed to allow that. Great name, too!
ThoughtBadger: Ooo, you really took my idea apart, didn't you? 
I only partially had my tongue in my cheek. I agree that part of the charm of the bike it its simplcity, though that isn't the reason that most people who commute on bikes in Oxford like them: it's because they are cheap and they get you from A to B without having to worry about parking and so on. Nor do I see how adding one small component would necessarily destroy the simplicity. Some people have hub dynamos which aren't at all transparent in their function, or particularly simple, but they serve an important purpose.
Of course, it wouldn't be worth using unless it worked well, and I'm a biologist, not an engineer. I agree that much of the problem is with the number of cars on the road, but it's a bit of a vicious circle -- if people don't feel safe cycling, then they won't, which means more cars on the road. So if this technology did work well, it might encourage more people off the roads and on to bikes.
Heh, it's just an idea, and I wouldn't force anyone to use it 
3
Although my first thought was that this would be best designed by Heath Robinson (with lots of pulleys, flywheels, umbrella parts, and knotted string), mature reflection leads me to believe that perhaps De Selby (from "The 3rd Policeman") could help you in constructing this. Or maybe there might be something to be gleaned from the writings of the noted obsessive cyclist, playwright, protodadaist, and maniac Alfred Jarry. The discipline he invented - Pataphysics, which if I remember rightly is to do with the discovery of solutions to nonexistent problems (not that different to some branches of advanced maths really!) could be of some help.
Good luck with it anyway! 
by ThoughtBadger @ 10/11/2003 9:12 pm • Permalink •
4
Seems someone else has beaten you to automatic stabilisers...
by Phil @ 12/11/2003 1:11 pm • Permalink •
5
Phil: Very interesting! My only other exposure to monowheels was a hilarious Scrapheap Challenge where they had to build a single-wheeled motor vehicle. I had tears of laughter running down my face as one of the riders (sitting astride -- and inside -- the wheel) accelerated a bit too fast and nearly did an impression of a hamster in a running wheel. I didn't quite understand what the 'digitally encoded learning key' was all about though -- how much does it need to learn? All it's got to do is close an electrical circuit.
1
I've never ridden a recumbent but I've always imagined slow speed stablity to an issue although I have no idea why. I've had plenty of stability issues on a standard road bike -- notably when I could not free my feet from clipless pedals and tumbled over at a stop -- sometimes with aprehension as I was suddenly a very low profile object at the crest of a hill, for example.
Wouldn't a modifed set of training wheels solve your problem? While a electronically controlled retractable system sounds nice, it seems like it would add unneeded complexity. (Although, maybe a physical control is possible through the increase of wind drag on the stabilizing wheels: i.e. as speed increases enough lift is generated to lift the wheel from the pavement.) You could call them "Fly Wheels™.----- I assume your tongue is in your cheek, but will reply in a boring and literal manner.
Bicycles are wonderful things. They are beautiful machines because they are simple. Anyone can take a bicycle apart and reassemble it, and you can see how everything works just by looking at it. What you suggest would destroy this, but apart from this aesthetic objection, I think it unlikely that the convenience offered by your idea would offset the disadvantages caused by the the additional weight and bulk. It further occurs to me that the convenience might be at best dubious, as at least you know how far your foot is from the ground at any one time, which would be unlikely to be the case for the wheels on your proposed device. I think your idea would cause quite a few spills!
The real problem you describe is political not mechanical, namely the quite ludicrous number of cars (including my own) on our roads, and in particular in our towns and cities.
by ThoughtBadger @ 10/11/2003 12:11 pm • Permalink •