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Countersteering

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Re: Countersteering

#61

Post by CraigJPerry »

KennyBlanken wrote: post #48
HPsquared wrote: post #23

Earlier quoted context omitted.

On the second point (the need to maintain light acceleration) I'd always thought this was more to counteract engine braking - if there is engine braking, that is more demand on the rear tyre, kind of like applying the brake - which takes up a bit of the "available" friction that could be used for cornering.

I can't speak to motorcycles, but when driving a car at the track there's "maintenance throttle" which is partly to counter the slowing you get from the tires scrubbing, and partly to balance 'weight'; most cars are far heavier up front than in back, so a bit of throttle puts a bit more weight on the back of the car, which helps keep the front outside tire from getting overloaded but also puts some weight on the back…

That’s right, in a car as you go into a corner you first steer a little bit, the car then “takes a set” - i have no idea where that terminology comes from but it just means the car moves to a steady state of loading up the outside suspension. Once you feel the car has taken a set, you can crank on a lot more steering. I’m describing it as two phases but the best drivers smooth both of these phases into one flowing motion - slowly steer at first then steer faster. Doing it in this two phase approach allows for far higher lateral g to be built in the turn than if you just smoothly turn at the same rate. You extract more grip because you build weight over the tire before asking it to grip and grip is parlty a function of weight on the tyre.

In most car drivetrain configurations you’d then use a balanced throttle through the turn.

You can use a balanced throttle on a bike too - many people do - but all race bikes and most advanced riders even in non race scenarios will use a slight acceleration not a balanced throttle because where in the car you want to settle the suspension with a heavy loading equally on your two outside wheels (e.g. in an FR layout car) on a bike you want to have around 65% weight on the rear.

There’s a similar effect with the Porsche 911 - it’s an RR layout with 12 inch wide tyres at the rear and a slight acceleration is optimimum for it.

Re: Countersteering

#62

Post by agurk »

I got a new (to me) motorcycle this year for a long trip I was planning and one of the things that surprised me was how much countersteer it needed to navigate tight mountain turns. I could definitely feel it in my arms at the end of each day.

A few thousand kilometers into the trip I changed the front tyre as it had hit the wear bars and was amazed how completely it changed the handling of the bike. Instantly I stopped needing to consciously countersteer to enter turns and needed to shift my weight in the saddle a lot loss too.

My assumption is that the new tyre has a cross-section that's a lot rounder than the old/worn tyres. I would have taken photos to compare them if I had realised that it would make such a difference. It was also a different brand (I didn't have much choice when I changed it) which also would have brought a different profile with it.

Re: Countersteering

#63

Post by d1l »

CraigJPerry wrote: post #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 fron…

Twist of the wrist is fantastic, as is the video, which can be found on YouTube. Agree with everything you said, and I'm curious: what do you ride? I've been tracking a mostly-stock R6 for the last 5 years, A the last 3 or 4. One thing I thought I'd add is that with motorcycles, the rider is a significant fraction of the total mass, so your position on the bike can greatly affect the center of gravity. You see guys leaning off the bike (towards the apex of a corner), which allows the bike to stand up taller, thus requiring less lean angle/more contact patch, which allows for higher speed and better grip at corner exit.

Oh and another surprising thing: on track I never use the rear brake when braking hard. Why? Hard braking lifts the rear wheel, and when you use the rear brake it becomes incredibly easy to lose rear traction!

Re: Countersteering

#64

Post by cdot2 »

ehnto wrote: post #53
wildrhythms wrote: post #30

Earlier quoted context omitted.

How does this happen? In the U.S. we have the Motorcycle Safety Foundation (MSF) which teaches a basic motorcycle riding course, and can give you a certificate for a motorcycle endorsement on your state license. One of their only prerequisites for the course is that you can ride a bicycle, because it guarantees the rider understands countersteering at low speeds before getting anywhere near a motorcycle.

The MSF isn't mandatory though is it? Also, statistics suggest a lot of the motorcyclists who get killed are doing it without a license anyway (or registered bike, or helmet...).

It is for some states. I know here in Texas it is.

Re: Countersteering

#65

Post by pryelluw »

agurk wrote: post #62

I got a new (to me) motorcycle this year for a long trip I was planning and one of the things that surprised me was how much countersteer it needed to navigate tight mountain turns. I could definitely feel it in my arms at the end of each day. A few thousand kilometers into the trip I changed the front tyre as it had hit the wear bars and was amazed how completely it changed the handling of the bike. Instantly I stop…

Nice, what bike?

Re: Countersteering

#66

Post by koonsolo »

CraigJPerry wrote: post #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 fron…

Motorcycle physics are very interesting to say the least. My favorite is this:

What happens to the suspensions when you brake? Front one compresses while the back one extends. That one was easy. Now this:

What happens to the suspensions when you accelerate? Front one extends while the back one... also extends.

Motorcycles are specially designed to have this last behavior.

Re: Countersteering

#67

Post by thefz »

ehnto wrote: post #52
thefz wrote: post #22

In mountain biking where you turn more by leaning the bike and rotating the hips, it is very evident that briefly steering by rotating the handlebar to the opposite direction points the head tube of the frame right into the turn, and then it's just a matter of straightening the handlebar and leaning into the corner.

I think the hips is mostly about the ergonomics of getting the right weight distribution for the bike, but the countersteering is the same. lean the bike over with the opposite steering input, and the whole situation leans over (including you!)

Turning the hips does a lot of subtle things, it impresses a rotational force to the rear wheel helping it to pivot on itself, and a rotational force into the pedals to further help the frame to rotate on itself. Further than that, it forces your head to turn into the direction you are heading and your shoulder line to stay parallel with the handlebar.

Man, bike-human mechanics are complicated.

Re: Countersteering

#68

Post by vceder »

wildrhythms wrote: post #30
frankdejonge wrote: post #14

In the Netherlands, countersteering is part of any motorbike practical exam. This is not standard in a lot of companies, but it is such an essential skill. It literally saves lives.

How does this happen? In the U.S. we have the Motorcycle Safety Foundation (MSF) which teaches a basic motorcycle riding course, and can give you a certificate for a motorcycle endorsement on your state license. One of their only prerequisites for the course is that you can ride a bicycle, because it guarantees the rider understands countersteering at low speeds before getting anywhere near a motorcycle.

In EU motorbikes fall under a different license then cars, so it involves both practical and theoretical test. What I know from the Swedish licenses is that the motorbike one is considered the more difficult test to pass.

There is a "high speed" slalom course you have to do as part of the test and it's impossible to do it without counter steering through it.

Re: Countersteering

#69

Post by projektfu »

HPsquared wrote: post #23
CraigJPerry wrote: post #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 fron…

On the second point (the need to maintain light acceleration) I'd always thought this was more to counteract engine braking - if there is engine braking, that is more demand on the rear tyre, kind of like applying the brake - which takes up a bit of the "available" friction that could be used for cornering.

I would say it's more to keep some weight on the rear wheel and prevent a low-side crash. When the bike is slowing down the weight shifts to the front, whether through friction braking or engine braking. If you are already at the correct speed, lightly accelerating helps bring you through the corner with more even weight on the wheels. Incidentally, race car drivers do the same thing, except when drifting, but you almost never see intentional drifting in road racing.

Re: Countersteering

#70

Post by projektfu »

ehnto wrote: post #55
Hamuko wrote: post #40

Earlier quoted context omitted.

> Anyone who rides a single-track vehicle will instinctively do it any time they turn. I've seen videos that suggest otherwise. Not linking it, since the last time I did, I got downvoted to hell and back for it.

You can't turn a bicycle or motorbike without counter-steering, so these people are just not turning their bikes? It's not possible to not countersteer as the bike would lean to the wrong direction and you'd turn the wrong way (since you'd have been initiating a countersteer, afterall). Are you seeing people just manhandle the bars the wrong way in emergencies? I could believe that. https://www.youtube.com/watch?v=9c…

That's exactly it. Countersteering is a learned behavior that people aren't aware they do. They will describe it as leaning into the turn or whatever. Then, when they are in an emergency and need a tighter turning radius, they instinctively put in the wrong input and the bike straightens up. Explicitly teaching countersteering helps teach them to respond to emergencies with the correct input.
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