Pillar of Wisdom - Gyroscopic forces...not

[Tuxstir]

without reading all the comments, last year i think.. i remember seeing a test done, where they used a gyroscopiclly neutral bike, and it still remained upright under speed... they effectively proved that the gyroscopic forces do not keep a bike upright..

 

 

http://janheine.wordpress.com/2011/04/27/bicycle-stability-everything-works-together/

Edited June 10, 2013 by tedibear

[Robrider]

Part of the reason that braking in a corner makes a rider unstable is that this fights the gyroscopic forces that are in play. When this deceleration happens suddenly (like when braking) the wheel will want to "stand up" and this greatly affects the stability of the rider throuhg a corner.

 

Note: when I say corner, I'm talking about really fast bermed cornering with the implementation of countersteer.

 

To be honest, I don't think that's gyroscopic forces. The main reason being, that an accelerating/decelerating wheel doesn't show any gyroscopic forces. If this were so stopping in a straight line would cause you to fall over. I think this can be explained in another way, but let me think about it for a bit. I might change my mind (see the light)

[patches]

I'd like to respond but quickly educate me on a X-up and whip?

 

 

Watch at 3:00 (X-up then bar spin). Done quite fast so as to minimise effect on stability.

Then Skip to 4:13 (whip). The rider uses a combination of the gyro on the front wheel and body movement to "pull" the bike sideways.

[DJR]

Ever tried riding with a seized headset? It is impossible to stay upright.

 

Try balancing your bike on its BB and spin both wheels...... See if the bike stays upright.

 

Pain or Shine (a really crafty rider) and myself once tried to ride a very unusual bmx at a school fair. The headset was modified with a roller gear to turn the front wheel left when you turned the handlebars right. No matter how hard we tried, we ended up on our ears within metres. I tried to cheat by not pedalling, simply to push off and let it free. He tried to wheelie. We still managed less than 5 metres. Most people fell of on their first pedal stroke.

Edited June 10, 2013 by DJR

[Johan Bornman]

cut cut cut cut

 

I disagree with what you said about gyro effects in the corner. The gyro effect has an initial effect as you lean. But once the wheel is "leaned" the gyro effect stops. This to me means that in a long corner you would have trouble steering. I think gyro has little to no effect, even in a corner.

 

 

cuty cut cut cut.

 

I hope I didn't say or imply that. You are right, the effect is only initially. But don't see why you would have a problem steering in a long bend. You'll do the initial lean with all its effects and then stay like that. To compensate, you lean more or less and it settles all over again. Did I miss something?

[DJR]

I knew this was going to be interesting - cool thread JB

[Cassie]

Anyone thought about "educating" Mr Badenhorst???

 

Great Post JB...took me a while to get my mind around all of that...

[Pappa Bear]

 

 

Pain or Shine (a really crafty rider) and myself once tried to ride a very unusual bmx at a school fair. The headset was modified with a roller gear to turn the front wheel left when you turned the handlebars right. No matter how hard we tried, we ended up on our ears within metres. I tried to cheat by not pedalling, simply to push off and let it free. He tried to wheelie. We still managed less than 5 metres. Most people fell of on their first pedal stroke.

 

We had a simaler bike at our school.....at a fair..... I belive that you should try riding such a bike cross armed, left hand on the right grip, and right hand on the left grip. I once did this on my bike, while at school, and just moered over..... You should try it! Or not!

[Johan Bornman]

https://www.youtube.com/watch?v=4aJzYioSDi4

 

Watch at 3:00 (X-up then bar spin). Done quite fast so as to minimise effect on stability.

Then Skip to 4:13 (whip). The rider uses a combination of the gyro on the front wheel and body movement to "pull" the bike sideways.

 

OK, I think I get it but it was quite fast and I'm didn't replay enough. What I think is happening there is the gyro effect, but it has nothing to do with balancing.. Do the experiment I suggested with the spinning wheel (but hold both ends of the axle to help you, then mock-do an X-up and whip and you'll see why it moves the bike - 'cause it can. On the road, there is no way that it can move like that.

 

 

BTW, the video you first posted is about angular momentum. It is a different issue. Just try my experiment and keep a wheel handy when posting. Once you've observed the first effect, I'll show you another trick.

[Robrider]

Part of the reason that braking in a corner makes a rider unstable is that this fights the gyroscopic forces that are in play. When this deceleration happens suddenly (like when braking) the wheel will want to "stand up" and this greatly affects the stability of the rider throuhg a corner.

 

Note: when I say corner, I'm talking about really fast bermed cornering with the implementation of countersteer.

 

Ok, I've thought about it, I don't think it is gyro forces causing this.

 

When the bike is leaned over, it is riding on the side knobs. If you apply brakes, the force that touches the ground will be on the side of the tyre, not the centre line. This off centre force will cause the tyre to go "toe-in", or in other words, sharpen the corner, causing the bike to stand up right.

[Robrider]

I hope I didn't say or imply that. You are right, the effect is only initially. But don't see why you would have a problem steering in a long bend. You'll do the initial lean with all its effects and then stay like that. To compensate, you lean more or less and it settles all over again. Did I miss something?

 

I think we are in agreement

[Lucky Fish]

Quote 'Johan Bornman' the in the OP.

 

'Cyclists and motorcyclist instinctively know that to turn right, you lean right and left, you lean left. We don’t turn the handlebars, they somehow turn themselves, we just lean.'

 

On a point of order. To turn RIGHT you first have to turn the handlebars to the LEFT (to break balance), before you can start to 'lean' into a corner. (It is impossible to make a bike turn to the right, assuming of course, that the bike is moving and you are balanced on the bike. by turning the handlebars to the right!)

 

If you don't believe what I have said, go ask any motor cycle racer how hard they have to turn 'away' from the intended direction under braking and with sticky tyres to make the bike 'lean' into the corner.

 

Alternatively just Google. LOL

[BergForce]

Quote 'Johan Bornman' the in the OP.

 

'Cyclists and motorcyclist instinctively know that to turn right, you lean right and left, you lean left. We don’t turn the handlebars, they somehow turn themselves, we just lean.'

 

On a point of order. To turn RIGHT you first have to turn the handlebars to the LEFT (to break balance), before you can start to 'lean' into a corner. (It is impossible to make a bike turn to the right, assuming of course, that the bike is moving and you are balanced on the bike. by turning the handlebars to the right!)

 

If you don't believe what I have said, go ask any motor cycle racer how hard they have to turn 'away' from the intended direction under braking and with sticky tyres to make the bike 'lean' into the corner.

 

Alternatively just Google. LOL

 

Also wanted to make this point, but that initial opposite turn to brake balance is such a small movement and almost instinctive that it is probably insignificant in this debate.

[blacksmith]

Ok, so can I throw a gyro in the works?

 

Edited June 10, 2013 by blacksmith

[Johan Bornman]

Quote 'Johan Bornman' the in the OP.

 

'Cyclists and motorcyclist instinctively know that to turn right, you lean right and left, you lean left. We don’t turn the handlebars, they somehow turn themselves, we just lean.'

 

On a point of order. To turn RIGHT you first have to turn the handlebars to the LEFT (to break balance), before you can start to 'lean' into a corner. (It is impossible to make a bike turn to the right, assuming of course, that the bike is moving and you are balanced on the bike. by turning the handlebars to the right!)

 

If you don't believe what I have said, go ask any motor cycle racer how hard they have to turn 'away' from the intended direction under braking and with sticky tyres to make the bike 'lean' into the corner.

 

Alternatively just Google. LOL

 

Nothing LOL about this.

 

The old counter steer argument again. Another myth, on google or elsewhere. You don't have to counter steer at all. I'll prove it by giving you a situation where you CANNOT counter-steer: riding no-hands. You still steer just like as if your hands are on the bars.

 

You don't have to turn a little bit left before turning right. Only old ladies in white Toyota Corrolas do that. There is also no such thing as breaking balance. It is not a locked-in scenario, you are constantly steering this way and that way without breaking anything.

[blacksmith]

damn, can't get this embedding thing right. Here's the link