I kind of have to disagree with the answer slightly. If Sir Richard was bolt upright and jerked the handlebars to the left, the bike would go left, or straight, but poor Sir Richard would be thrown to the right.
Yeah, I can see that, but I don’t think it’s right given that Sir Richard was going fast. At that speed, when jerking the bar to the left, the gyro effect of the wheels will create a lean to the right. I don’t think there’s much chance of resisting that at speed. That then will result in a right turn.
I’ll grant you though that if a bicyclist riding fast were to deliberately jerk the bar much too hard to the left than a good rider would ever attempt, momentum would probably toss him off expeditiously, mostly straight ahead, not off the road as the puzzler describes Nigel’s description. Maybe that’s what you are thinking?
So maybe their answer is quasi-bogus??
A good rider at low speed can make the bike do what you say, ie, go left when turning the wheel the left (I just tried that). This is what it takes to make a very slow speed turn, such as trying to ride a figure eight. It seems that at low speed, lean is more important than what happens to the handlebar. That explains riding no hands and making turns (I was pretty good at that when I was 12). I just think that at high speed, you can’t do what you say, and it’s after dark now so I’m not going to go out and confirm what I suspect is true. But steering the bar to the left will cause an instant lean to the right, and that results in turning right.
My point of contention with their answer is that I think there’s more physics involved than they explain, but since I’m not exactly sure how it works, I’m can’t really stand firm on that. But I think it’s related to the arc that the tire cuts when it is not vertical. But I’m on thin ice there!
I do think there’s some effect of the rider being familiar with the dynamics of a bicycle. I know that if I’m riding fast and need to turn a bit, my whole body just naturally knows what to do, I don’t really think about it. I lean a bit while I’m nudging the handlebar, it’s not one action causing the other. But I NUDGE the bar, I don’t jerk it at speed.
Maybe the physics is harder to see on a bicycle just because the rider is heavier than the bike and rider weight can overcome some of the gyro effect. But on a motorcycle, I think it’s really clear and obvious that pulling the left handlebar and pushing the right initiates a RIGHT turn. It takes only a very subtle touch at slow speeds to make the motorcycle lean and turn.