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Countersteering

en.wikipedia.org

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Re: Countersteering

#4
post #3

also https://en.wikipedia.org/wiki/Scandinavian_flick

The original article is about counter steering in bicycles and motorcycles to initiate a turn, not counter steering (or "opposite lock") in a car (or motorcycle/bicycle) in response to oversteer.

That said, they're quite all quite interesting phenomena in vehicle dynamics.

Re: Countersteering

#5
post #2

This Veritasium video touches upon the same phenomenon: https://www.youtube.com/watch?v=9cNmUNHSBac

Came here to cite this video. It’s wonderfully done. I think I knew it intrinsically but had never thought about it until this video came out.

Re: Countersteering

#6
It helps to think of the bicycle/motorcycle as an inverted pendulum. To sustain an acceleration in a given (lateral) direction, it must lean in that direction.

Countersteering helps to control/initiate the lean angle. To lean to the right, the rider steers to the left and the wheels (at the bottom) move to the left while the centre of mass stays where it was initially, thus the angle begins to lean to the right, initiating a steady rightwards acceleration.

Re: Countersteering

#7
There’s a lot about riding a motorbike that feels counterintuitive. The way this article is written it sounds like you can only initiate the steer with a counter steer but even if you’re already in a bend you can provide a counter input to tighten your line and steer harder. It’s taught pretty early on for new riders and it saves lives.

There’s loads of other weird things, because the rear tire is wider than the front, the contact patch is bigger at the rear, so to extract maximum grip you need a rearward weight transfer, so lightly accelerating in a turn is optimal. Even when not pursuing max grip you’d still do this to keep the envelope large around your actual grip requirements.

Although The front wheel has a smaller contact patch, the contact patch at the front is often a different shape- the front wheel is often a larger diameter so it has a longer but narrower contact patch than the rear. That makes for a vehicle that tracks and responds differently over uneven ground at the front vs the back which leads to you needing to let the front move itself, a relaxed grip is needed on the bars over uneven surfaces, otherwise you will transfer so of that motion from the handlebars, through your body to the pegs and the seat. That will lead to a loss of control. Utterly counter intuitive that to retain control over rough ground you want to almost let go of the handlebars.

There’s two great books - for direct machine control, “a twist of the wrist” volume 2 by keith code and for more abstract how to think about machine control - not So much how to steer but why to steer and where to - then roadcraft by the uk police is another great book.

Re: Countersteering

#9
When you lose traction in your car from rain or snow, your instinct is probably to countersteer, but you should instead steer into the turn and countersteer when you regain control.

I can't remember if they actually taught that in driving school, but my dad had me deliberately lose traction repeatedly in a parking lot in the snow to get the hang of it. It saved my life a few times because I was a reckless idiot as a teenager.

Re: Countersteering

#10
I'm now imagining some poor child's dumbfounded look as a HackerNews parent explains how to ride a bike by breaking down countersteering. lmaoo
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