Comment by tome
8 years ago
Have you actually tried turning a bicycle without countersteering? I have, the last time the topic was discussed on HN. I found I was able to turn without any perceptible countersteer. It's technically possible that I do have to countersteer for a small number of miliseconds over a small number of milimeters, but my experience leads me to doubt it.
Bikes have "rake"[1]- the tilt in the axis of steering. In a bike with 90 degree rake you would always need to countersteer.
When the wheel is forward of the axis of steering, you don't need to countersteer for small turns. When you turn the bars, the contact point on the wheel moves forward and to the side, dropping the front of the bike down and tilting it into the direction of the turn for you. That mimics the effect of countersteer. It's also one of the factors that makes some bikes, like mopeds, easier or harder to control.
During harder turns, the amount of lean created by the rake angle is less than required and you do need to countersteer. It's very hard to notice even when you're actively looking for it though.
[1]: https://ep1.pinkbike.org/p4pb9516905/p4pb9516905.jpg
If you have a normal bicycle without modifying the steering column then you were using countersteer whether you realized it or not. Even if you weren't toughing the handlebars, the lean initiates a countersteer. And you need countersteer again in the opposite direction to re-center yourself. If there's video or experimental setup info I'd like to see it.
Based on live TV illustrations I've seen, using paint on a wheel, the counter steer can amount to as little as 1cm. I'm not sure if that is perceptible without the paint trick.
A moped (and I assume a motorcycle) is a lot harder to turn without countersteering. I’m not sure if that’s because it’s more massive or what.
Anyway, learning to ride a moped was when I first consciously discovered countersteering. It made things a lot easier after that point.
It could be based on speed rather than mass. Above 5-10 mph or so, you turn a motorcycle with pretty much total countersteering, forcefully pushing forward on the inside hand grip to get the motorcycle to lean over. The faster you're going, the further you need to lean the motorcycle.
That makes sense too.
The geometry is set up to be stable at a higher speed. Even then some sports bikes require a steering dampener to prevent "speed wobbles" (which, yes, are an actual thing and are much worse at 260kph than at 30kph on your BMX when you're a kid.)
Is "speed wobble" anything like the Jeep "death wobble" (actually can happen on any 4wd vehicle, but Jeeps seem to have the problem more as steering and suspension components wear)?
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