Countersteering vs body leaning?

**R-Soul** · 18th May 2010, 17:41

Originally Posted by bogan

firstly weight is a bit of an ambiguous term in physics, most say gravity, or mass, depending on what is meant. Leaning in or out creates exactly the same moment, conservation of angular momentum.

Weight is mass accelreated by gravity G, in Newtons (as a force). W= m X G. Nothing ambiguous about it.

Yeah I guess you get the same moment. So then (subjectively) why does it feel a lot more controlled when you lean into a corner (even at low lean angles when suspension differences should be minor)?

**bogan** · 18th May 2010, 17:56

Originally Posted by R-Soul

Weight is mass accelreated by gravity G, in Newtons (as a force). W= m X G. Nothing ambiguous about it.

yeh, but many say weight when they mean mass, I just don't see weight much in physics texts, does it even have a symbol?

Originally Posted by R-Soul

Yeah I guess you get the same moment. So then (subjectively) why does it feel a lot more controlled when you lean into a corner (even at low lean angles when suspension differences should be minor)?

fear barrier type stuff I think, cornering one style so much that different style seems wrong.

**MSTRS:Me** · 18th May 2010, 17:57

I don't know all the technical terms. But I have a fair grasp of cause and effect.
What I can say is if you get something wrong enough, you WILL have a moment...

**R-Soul** · 19th May 2010, 07:20

Originally Posted by bogan

yeh, but many say weight when they mean mass, I just don't see weight much in physics texts, does it even have a symbol?

fear barrier type stuff I think, cornering one style so much that different style seems wrong.

Normally in physics texts it more strictly regarded as a force F. its ony when you have a mass on Earth accelerated by our gravity acceleration constant G then its regarded as being 'weight'. That is what weight actually means. Although the term is confused by incorrect usage of it (eg "I weigh x kilograms" - kilograms actually being a mass unit, not a force unit). Its also further confused by the aditional imperial terminologies used.

But the unit of weight is measured in is Newtons, same as force.

You might be right about the fear barrier - I have been wracking my brain, and the COM of both bike and rider should stay the same. Ah well, at least that means that I have ingrained good techniwue, so that when I do it wrong, it feels bad, right?

**Crisis management** · 19th May 2010, 08:26

Originally Posted by MSTRS

Sorry, but you are wrong.
The bike does begin to lean to the side you weight, BUT in doing so, the steering head reacts by turning outwards, which 'flops' the front tyre onto the side you have leaned towards, which in turn pulls the steering head etc back to the 'correct' side thereby the bike then turns in tha direction. It is EXACTLY the same as bar input. Just not as precise.

No your wrong.....apologies for wandering into this physics discussion but there seems (I may have misunderstood this) to be an understanding that the bike leans into the side you weight a peg on, this does not happen.

Assume you are travelling in a straight line, put weight on the right hand peg and the bike will lean to the left, the bike & rider act as a unit to maintain balance, when the rider moves weight to one side the bike leans the opposite way to maintain balance. Try this out by standing on the pegs, hands off bars at 50km/hr in a straight line and steer with the pegs.

The reason this is important is that peg weighting and effective countersteering are closely linked, to paraphrase Mr Code:
To initiate a left hand turn, weight the right hand peg at the same time as you push the left hand bar forward, not only do the two actions initiate a sharp lean to the left of the "body" of the bike but the physical action of pushing down (weighting the peg) of the right leg and pushing forward with the left arm are physiologically linked, they are sympathetic movements of the body. Try reaching up high with the left arm and you will find you have extended the right leg at the same time.

This is (IMHO) the beauty of motorcycling, the close link between the machine and the human body, it's a dance not a science experiment.

Before you refute all my claims, bugger off outside and try it out, get in harmony with the machine.

**MSTRS:Me** · 19th May 2010, 08:39

Hmmmm...might have to try that.
Right or wrong about which side goes which way, peg weighting still initiates counter steering, tho

**Crisis management** · 19th May 2010, 08:55

Originally Posted by MSTRS

Hmmmm...might have to try that.
Right or wrong about which side goes which way, peg weighting still initiates counter steering, tho

It's subtle, the reason the "weight the side you want to turn to" theory exists is that the intial effect is small, so the bike seems to fall into the side you weight once countersteering takes over.
You're right about peg weighting initiating countersteering, just maybe not the way you assumed it occurred. A good way to see this is get that tarty wife of yours on a bike, riding away from you, standing on the pegs and weighting pegs alternately, you will get a graphic illustration of the actions/ reactions (and a good laugh with any luck).

I suggest this purely in the interests of science.........

**MSTRS:Me** · 19th May 2010, 09:10

Originally Posted by Crisis management

A good way to see this is get that tarty wife of yours on a bike, riding away from you, standing on the pegs and weighting pegs alternately, you will get a graphic illustration of the actions/ reactions (and a good laugh with any luck).

I'm not sure that I'd see what the bike was doing. I know what her arse looks like in leather...

**bogan** · 19th May 2010, 09:18

Originally Posted by Crisis management

No your wrong.....apologies for wandering into this physics discussion but there seems (I may have misunderstood this) to be an understanding that the bike leans into the side you weight a peg on, this does not happen.

Assume you are travelling in a straight line, put weight on the right hand peg and the bike will lean to the left, the bike & rider act as a unit to maintain balance, when the rider moves weight to one side the bike leans the opposite way to maintain balance. Try this out by standing on the pegs, hands off bars at 50km/hr in a straight line and steer with the pegs.

yeh that sounds right, but so is mstrs isn't he? weighting the peg shifts the person to the other side of the bike, so the bike go ever so slightly the other way, which ever so slightly steers the front to the outside (peg weighting side), and that initiates a bike and person lean to the inside.

Originally Posted by Crisis management

The reason this is important is that peg weighting and effective countersteering are closely linked, to paraphrase Mr Code:
To initiate a left hand turn, weight the right hand peg at the same time as you push the left hand bar forward, not only do the two actions initiate a sharp lean to the left of the "body" of the bike but the physical action of pushing down (weighting the peg) of the right leg and pushing forward with the left arm are physiologically linked, they are sympathetic movements of the body. Try reaching up high with the left arm and you will find you have extended the right leg at the same time.

This is (IMHO) the beauty of motorcycling, the close link between the machine and the human body, it's a dance not a science experiment.

Before you refute all my claims, bugger off outside and try it out, get in harmony with the machine.

yup, born to ride! But those of us planning to build these things (or just have an interest) need to treat it as a dance and a science experiment.

**Dare** · 19th May 2010, 09:26

Haven't got anything amazing to add to this except for a wee story.
One time my acc cable broke at some ungodly hour and instead of languishing by the side of the road I decided to crank the idle up and clutch it home. It worked but that's not the point of this story, on the way I realized it was something of a cruise control. Take both hands off the bars (feels a bit like doing it on a pedal bike only more solid) and you can turn it pretty sharply (it is a 250 after all). It wouldn't work much at high speeds (/not stable below about 10) and you could get some serious wobble if you're not careful. BUT. It is possible to a fair degree.
On the no BS bike you might notice that the rider is hopping all over the place but keeping his CoG more or less OVER the bikes so that it doesn't lean, that is not a very clear demonstration IMO.

**Geemsee** · 19th May 2010, 13:21

Originally Posted by schrodingers cat

Read a couple of really interesting articles recently.

http://www.sportrider.com/tech/146_0110_art/index.html

http://www.sportrider.com/tech/146_0302_art/index.html

THe discuss the mechanics of counter steering vs Body leaning.

My question is: They talk about weighting the footpegs to influence the chassis. I can sort of see what they are getting at but wind myself into knots experimenting on the (empty) road.

Can someone please explain in detail the hows/whats/Whyfors of this?
Esp the appropriate timing and sequence of the rider inputs

Personally, I subscribe to the Mick Doohan 'school' of motorcycling technique or "basically I don't really know what I'm doing"!

*

(*I think he said this in an interview once)