Countersteering Confession

[Edbear]

Now that I am concious of it I have found it is easier to hold lines at reasonable speeds.

Sorry, I have to bite! How do you hold the line at unreasonable speeds...?

[Pixie]

The wheels move out from under the bike to the side while the centre of gravity of the bike stays put, hence the bike topples and I turn. I tested that out last year when I first joined this site. But I'll report on the bmx wheel test tomorrow...

OK genius
Coast down a straight incline,on your bike,with your hands off the bars.
Lean your body as far to the left or right as possible,this will move the C of G of the bike/rider system out from the center line of the bike (outside of the tyres contact patch)
Now see if the bike steers from a straight path

[Kflasher]

Who would have guessed there is a science to having fun

[McJim]

OK genius
Coast down a straight incline,on your bike,with your hands off the bars.
Lean your body as far to the left or right as possible,this will move the C of G of the bike/rider system out from the center line of the bike (outside of the tyres contact patch)
Now see if the bike steers from a straight path

This works on a push bike but I've never had the guts to do it on a motorbike. Is it supposed to work on a motorbike too?

[sAsLEX]

......watch a sea king flying along - it flies on a lean!

Only got Sprites so will have a look at them next time I see them

Don't apologise. I'm guessing that square profile tyres are fine for the mud tracks that very early bikes had to deal with, but they wouldn't be suitable for concrete or tarseal at anything over 20k/hr.

WRONG again. There are a few who use car tires on the rear of their cruisers and find good results from them. Search if you dont believe me.

Well, maybe. But has anyone ever experienced having a car go left when you turn the wheel to the right ?

Yes, its called drifting......

[judecatmad]

Well, maybe. But has anyone ever experienced having a car go left when you turn the wheel to the right ?

Depends how fast you're going around the corner! Go too fast and you won't go in the planned direction!

But that's centripetal force versus friction as opposed to gyroscopic force. Cars definitely do experience forces pushing to the left when going into a right turn (hence why your inside wheels will lift if you're going too fast!).

I guess with a car, the fact that you have a fixed axis between 2 rotating wheels means that cars are not subject to the same gyroscopic forces - cars don't lean in the same way that bikes do.

My head hurts............

[Animal]

I was an aircraft engineer when I was young, so I can tell you from experience: Helicopters defy all aerodynamic conventions and fly by converting vibration into lift. An amazing phenomenon.

[Motu]

I don't know much theory,but I now how to drive on gravel.With the VW's I used to thrash around we could say polar inertia - throttle off and a flick of the wheel to the right....then start dialing in left lock as you come into the corner with the back end coming out to the left,some is to do with the camber of the road too.But I've definatly entered corners turning the wheel the opposite way to the corner....and looking through the passengers window going straight ahead! You can do it on a bike too...if you are brave enough.

And what is the rear wheel doing while all this countersteering stuff is going on? Back to our spinning bicycle wheel - you turned it right,and it tilted left....now tilt it left - it will turn left....and stand up too.

[McJim]

O-kay. Now I feel sea sick. I'm gonna forget about corners and move to Arizona after reading this thread.

[judecatmad]

I was an aircraft engineer when I was young, so I can tell you from experience: Helicopters defy all aerodynamic conventions and fly by converting vibration into lift. An amazing phenomenon.

Bumblebees also defy the laws of aerodynamics/physics too...apparently....

(useless item of trivia #652)

[petesmeats]

In my understanding there is a major interaction between many different components when turning a bike but put simply...

1. The Gyroscopic stuff helps us get the bike on a lean

2. The Lean makes the bike/rider COG move to the left/right of the contact patches on the road

3. The weight of the rider acts through the COG but is transferred down through the bike at the lean angle.

4. The force at the contact patch has a horizontal and a vertical component.

5. The vertical component supports the rider/bike weight and the horizontal component (acting toward the centre of the turn) Acts as the centripetal force which turns the bike through the corner.

6. The further the bike leans the greater the horizontal reaction force will be meaning that the bike can turn through a tighter angle.

7. Once the Horizontal reaction force reaches the max friction force (Tyre constant x Vert reaction force) of the tyre on the road the bike will fall and the rider will leave copious amounts of leather/skin/plastic/glass etc all over the ground.

That is my understanding of cornering...

EDIT: The Rear wheel contributes alot to this cornering

I experimented with it in the weekend going out to Akaroa and found that in fact there is another aspect to it...

If on a right hand corner I lean too far i will scrape my exhaust on the ground causing me to lose my concentration and only narrowly escape being inserted into a wall...

I reckon that if you want to learn the art of cornering the theory only really comes into it once you are competent... It is mainly just practice and trial and error (hopefully not catastrophic error) That will get you to the point where to go faster the theory must be known...

I'm also not completely convinced about the whole broomstick thing...

Feel free to correct me if i'm wrong about stuff cos i'm a youngun' with much to learn...

[Masterchop]

Arhh, Now I see why all you guys are so slow!

You think about it all to much.
Relax it just happens.

[marty]

the c of g always acts vertically down.

[thealmightytaco]

OK genius
Coast down a straight incline,on your bike,with your hands off the bars.
Lean your body as far to the left or right as possible,this will move the C of G of the bike/rider system out from the center line of the bike (outside of the tyres contact patch)
Now see if the bike steers from a straight path

I'm not sure which argument you're fighting for but...

OK genius
Of course the bike steers offline, the offset cog will cause the lean and then the bike to turn as camber thrust kicks in. But on a motorbike that bollocks might take a bit long, thanks to the gyroscopic ladida, and a persons balls being too small to accept such a lack of control.

But if you read back to where I tested the bmx wheel you'll find I've already surrendered to accepting the gyroscopic effect tips the bike over, if only to kickstart the whole operation at the least.

[Animal]

Bumblebees also defy the laws of aerodynamics/physics too...apparently....

(useless item of trivia #652)

This is true! I remember reading somwhere during my training that NASA had apparently studied their design (at some ridiculous cost) and declared them to be in defiance of all conventions. Yet the little bastards do fly! I know this because I personally collected one across my neck while doing a-hundred-and-plenty. The bruise was impressive, but got me no sympathy!

Anyway, cats rule!