Witchcraft?

**mickchaganis** · 11 Jun 08, 03:40 PM

Only just past my test a few weeks ago, friends talked to me about counter stearing, sounded like witchcraft to me! But read about it, understood it and started practicing it, WOW it bloody works and I didn't even have to rip the head off a chicken and rub it's blood on my elbows!!!

**Kenoir** · 11 Jun 08, 03:53 PM

Quote:

Originally Posted by mickchaganis

But read about it, understood it and started practicing it

I think the actual physics of it are right up there with astro physics! Now that Stephen Hawking has mastered the origins of the universe, he's going to be working on counter steering...... or did I just dream that bit?

**Paivi** · 11 Jun 08, 04:05 PM

Here's what June's Bike magazine said to illustrate it:

Imagine a pair of ice-cream cones stuck together at the fat ends. As long as the tips are an equal distance agove the surface of a table, the cones will roll in a straight line. But if one tip rests on the tabletop, our double-cone will roll in a circle around that point because of the cone's tapering profile - left tip down and it circles to the left.

Counter-steering works by using the tapered shoulders of the front tyre to make the bike turn. Pushing the left bar away from you makes the front wheel point right, which means it's running on the left hand shoulder of the tyre - so it will stop rolling in a straight line and instead describe a circle around a point to the left of the axle (and, hence, turn left).

**Kenoir** · 11 Jun 08, 04:08 PM

I'm sure Dr Hawkin will make it sound much more complicated!

**Kenoir** · 11 Jun 08, 04:09 PM

Nice tutu Paivi by the way

**Paivi** · 11 Jun 08, 04:12 PM

Tutu? It's an exclusive Dolce & Gabbana dress that Harrie got for me from Gecko Connection. Don't you know anything about fashion?

**mickchaganis** · 11 Jun 08, 04:33 PM

I'll have a flake in both my ice creams please, but only one with strawberry sauce

**Kenoir** · 11 Jun 08, 04:53 PM

Quote:

Originally Posted by Paivi

Tutu? It's an exclusive Dolce & Gabbana dress that Harrie got for me from Gecko Connection. Don't you know anything about fashion?

It is a very small picture you know!

And as for fashion, I was voted the best dressed centennial being in the known universe 3 years running!

**Gilps** · 11 Jun 08, 05:13 PM

Quote:

Originally Posted by Paivi

Here's what June's Bike magazine said to illustrate it:

Imagine a pair of ice-cream cones stuck together at the fat ends. As long as the tips are an equal distance agove the surface of a table, the cones will roll in a straight line. But if one tip rests on the tabletop, our double-cone will roll in a circle around that point because of the cone's tapering profile - left tip down and it circles to the left.

Counter-steering works by using the tapered shoulders of the front tyre to make the bike turn. Pushing the left bar away from you makes the front wheel point right, which means it's running on the left hand shoulder of the tyre - so it will stop rolling in a straight line and instead describe a circle around a point to the left of the axle (and, hence, turn left).

Bike ought to know better. That's not the reason it works. It's to do with centre of gravity and centrifugal force. Using bike's theory - going in a straight line and turning the wheel to the right will actually place the inside of the right tyre closer to the tarmac. Because of the rake of the steering the left side will be lifted away from the road. With the wheel now on the right hand side of the tyre the wheel will now turn right. Take a coin and try it. Lean it over to the right and push it along. What happens? It goes to the right. Only that's not what happens with CS is it.
What actually happens is that the contact patch remains in the same postition when you initiate the turn, it has to because of centrifugal force pushing it in a straight line. So, if the wheel is turned to the right, the whole front end of the bike is pushed to the left of the contact patch, thus moving the centre of gravity to the left and causing the bike to pull to the left.

**-=JK=-** · 11 Jun 08, 07:28 PM

Oh mate, you had to mention centifugal force, didn't you

As you know, there's actually no such thing, and it is a "pseudo" force, and doesn't appear anywhere in Newtons laws of motion.

Having said all that, it exists to describe the physics involved in masses rotating on a single plane(afaik), otherwise the boffin's head's explode, and it all gets very messy.

All totally beyond me, although i'd plump for something along the lines of the rotating mass of the wheel & tyre coupled with the tyre profile.

Not sure about the coin example, as it's not spinning quickly enough to want to stay upright & in a straight line, which is what you're trying to overcome with a bike wheel.

Interesting debate tho'.

All i know is, push the left bar & it goes left, push the right & it goes right. This is a good thing.

**stevel** · 11 Jun 08, 07:35 PM

Try putting that in Youtube, there's all sorts on there. Not much of it clears things up, but I reckon it's all to do wiith gyroscopic precession. So there

**billywiztheelder** · 11 Jun 08, 09:41 PM

I'm with you Gilps although I don't hold with the front tyre profile having anything to do with it.

The instant you push the left bar the bike is still vertical but the bike tries to follow the direction in which the front tyre is pointing i.e. to the right. Then this imaginary Reactive Centrifugal Force (which does not appear in Newton's laws of motion for an inertial frame of reference) forces the bike. who's Centre of Gravity is above the points of tyre contact with the road, to lean to the left.

The steering geometry i.e. forks angle of rake then forces the front wheel to follow the angle of lean. Try it with a push bike by holding the saddle, front wheel pointing straight ahead, lean the bike to the left. Which way is the front wheel pointing now?

If the front forks were perfectly vertical, as in a penny farthing bike it would point straight ahead and if the forks had a negative angle the reverse would happen!

**Cess pit** · 13 Jun 08, 12:27 PM

AAhhh.....physics, my favourite subject.

If one allows for the dangle angle, weights the left peg with the right foot and then divide your age by the number of fingers on your left hand...(those from Norfolk will need to make adjustments here) then you will magically find that you have negotiated you way into casualty.

Just push them bars guys and enjoy, I really don't care why it happens, just that it does...........

**sim1** · 13 Jun 08, 12:43 PM

Quote:

Originally Posted by Cess pit

AAhhh.....physics, my favourite subject.

If one allows for the dangle angle, weights the left peg with the right foot and then divide your age by the number of fingers on your left hand...(those from Norfolk will need to make adjustments here) then you will magically find that you have negotiated you way into casualty.

Just push them bars guys and enjoy, I really don't care why it happens, just that it does...........

As an apprentice on building site I always heard the witchcraft explanation of why my conduits always looked pished...The angle of the dangle is directly proportional to the throb of the knob provided the foreskin remains constant.

As far as countersteer goes..why bother about trying to explain the physics of it, same as why the bee cannot fly. It's voodoo, just live with it.

**sim1** · 13 Jun 08, 12:47 PM

Quote:

Originally Posted by Kenoir

It is a very small picture you know!

...

For those of you with IE7 use CTRL+mouse scroll wheel to zoom the page/pictures up

For those with Firefox - get the zoom add in and right mouse scroll I think.