ADVrider

Go Back   ADVrider > Riding > The perfect line and other riding myths
User Name
Password
Register Inmates Photos Site Rules Search Today's Posts Mark Forums Read

Reply
 
Thread Tools Search this Thread Display Modes
Old 07-09-2013, 06:30 AM   #781
Center-stand
Gnarly Adventurer
 
Joined: Nov 2008
Oddometer: 386
..

Have never meant ot imply that I ride with a death grip or tension, though sometimes I do tighten up a bit when I get in over my head.

I do want to go out and release the bars in a turn to get a feel for exactly what happens. I'll do that next chance I get.
Center-stand is offline   Reply With Quote
Old 07-09-2013, 03:29 PM   #782
lnewqban
Ninjetter
 
lnewqban's Avatar
 
Joined: Jan 2012
Location: Florida
Oddometer: 290
Cool2

Quote:
Originally Posted by Center-stand View Post
..
..........I do want to go out and release the bars in a turn to get a feel for exactly what happens. I'll do that next chance I get.
Don't release both ends, your bike may actually tend to straighten the curve and put you in a dangerous situation.

Releasing only the outside of the bar respect to the turn is a common practice in track days to ensure that both hands are not fighting each other.

The hand that remains holding the handlebar will feel any pull or push.
lnewqban is offline   Reply With Quote
Old 07-09-2013, 05:49 PM   #783
Center-stand
Gnarly Adventurer
 
Joined: Nov 2008
Oddometer: 386
..

Turn loose, don't turn loose, I'm so confused.

Read this: http://www.manicsalamander.com/artic...cycle-(!).aspx

This is an excerpt from the article: I think it explains a lot of things better than I have read previously, including my perception that the bike tends to right itself when releasing pressure coming out of a curve. It may be just a perception, but there are reasons why it feels that way.

......... Likewise, you need to steer the contact patches of a bike out from under it, so it falls, then arrest the fall by steering the contact patches to follow the top of the bike around the corner, then steer them even harder in the direction of travel than the top of the bike is going, in order to make the bike stand up again. It is often said that you recover from the lean by accelerating. Accelerating does widen your corner, thus making you go straighter. It does this by increasing the distance over which the sideways force of your lean acts. The physics adds up to the rule that a certain degree of lean, if you stay still on the bike, will result in a certain angular velocity (rate of directional change) at a certain forward speed. If you increase that speed by accelerating, it will not automatically change your degree of lean, but it will spread the force of the lean over a longer distance, thus diluting your ability to change direction, and you will go straighter. This is a natural and sensible thing to do when coming out of turns, but it is not sufficient to stand the bike up completely. It won't get the job done. You still need to finally steer the contact patch back under the bike.



Here's what acceleration in a corner does for you. It shifts weight to the rear, extending the fork, thus increasing rake and trail, which increases the self-correcting tendency of the steering. To the degree that you are leaning, this makes the bike stand up more. But it won't take you all the way, because that self-correcting force goes to zero as your lean goes to zero. Also, the faster you go, the more effective are your inputs to the handlebars, so it takes less and less motion of the bars to bring the contact patches under the bike the more you accelerate out of the turn. That reduces the trouble you need to go to in order to cancel the lean, but once again, you have to deliver that last nudge, to get the contact patches back under the center of gravity. Unfortunately, the contact patch takes more and more handlebar motion to steer, as speed approaches zero.



..

Center-stand screwed with this post 07-09-2013 at 06:02 PM
Center-stand is offline   Reply With Quote
Old 07-10-2013, 05:53 AM   #784
Rucksta
Chronic Noob
 
Rucksta's Avatar
 
Joined: Oct 2008
Location: Gold Coast
Oddometer: 2,568
Quote:
Originally Posted by Center-stand View Post
..I'm so confused...
That part I understood

Quote:
Originally Posted by Center-stand View Post
... Likewise, you need to steer the contact patches of a bike out from under it, so it falls ..
This part as well

Let me help confuse you more.



If I loft the front wheel coming out of a corner does the bike
  • spear off the road in a straight line ?
  • continue on the arc it was before the front wheel lifted?
  • do something else ?
Why is it so?
__________________
My bike is slow but the earth is patient.
Rucksta is offline   Reply With Quote
Old 07-10-2013, 09:56 AM   #785
SkiFastBadly
A beer? Yes, please
 
SkiFastBadly's Avatar
 
Joined: Mar 2007
Location: Woodinville, WA
Oddometer: 1,515
Quote:
Originally Posted by Rucksta View Post

If I loft the front wheel coming out of a corner does the bike
  • spear off the road in a straight line ?
  • continue on the arc it was before the front wheel lifted?
  • do something else ?
Why is it so?
You'll go straight...without a front tire contacting the ground you are at the mercy of Newton's first law.
__________________
The crows seemed to be calling his name, thought Caw.

2008 Buell Ulysses
2008 Triumph Scrambler
2004 HD Heritage Softail
SkiFastBadly is offline   Reply With Quote
Old 07-10-2013, 02:11 PM   #786
Center-stand
Gnarly Adventurer
 
Joined: Nov 2008
Oddometer: 386
.

Quote:
Originally Posted by Rucksta View Post

If I loft the front wheel coming out of a corner does the bike
  • spear off the road in a straight line ?
  • continue on the arc it was before the front wheel lifted?
  • do something else ?
Why is it so?
Too many variables. Who's holding your beer?

..
Center-stand is offline   Reply With Quote
Old 07-10-2013, 04:51 PM   #787
joexr
Banned
 
Joined: Jan 2011
Location: S.E.
Oddometer: 3,773
Quote:
Originally Posted by Rucksta View Post
That part I understood



This part as well

Let me help confuse you more.




If I loft the front wheel coming out of a corner does the bike
  • spear off the road in a straight line ?
  • continue on the arc it was before the front wheel lifted?
  • do something else ?
Why is it so?
It'll try to go straight. If you move your body to the side , the bike will turn the opposite direction , by forcing it to lean.
joexr is offline   Reply With Quote
Old 07-10-2013, 06:33 PM   #788
Center-stand
Gnarly Adventurer
 
Joined: Nov 2008
Oddometer: 386
..

Just wanted to add a couple more paragraphs from the article linked above.

This, and the paragraphs above, seems to suggest that the neutral time during a turn would be that portion of time when speed and turn radius are constant. If speed or turn radius changes then rider input is necessary to maintain lean and line and / or vice versa. Most riders, especially racers, will slow on approach and entering of a turn, then accelerate out of the turn, so neutral time would be minimal.

Excerpt from How To Steer a Motorcycle, Articles by Paul

,,,,,,,,,,,,,,And what about gyroscopic forces? They increase with wheel and engine speed. They are almost nil at walking speed, but if you have heavy wheels, like the cast aluminum mags on late-'70's Yamahas, they have a significant effect at 60MPH. Their overall effect, if you don't turn the handlebars, is to resist changing the lean of the motorcycle. Keep in mind, though, that only the front wheel's gyroscopic forces will make the motorcycle lean, since that is the one that you can turn to the side. There are also gyroscopic forces present in more parts of the motorcycle than just the front wheel. I just went out to my garage and took a motorcycle wheel, spun it on its axle, held it, and turned it different directions. Here are the results:

Regarding front wheel motion I have these observations. If you steer it left, it leans right. If you steer it right, it leans left. But it only leans farther as long as you steer farther. If you hold your steering angle, it holds its lean. If you steer straight again, it goes vertical. So the gyroscopic force has the same effect on lean as countersteering, but that force disappears as soon as you stop moving the handlebars, and reverses as you bring them back to center. This means that in that initial stage when you get the bike leaned over, gyroscopic force works for you in the front wheel, but as soon as you try to steer around the corner, it works against you, tending to stand the bike up. Obviously, we overcome that standing up force, because we can stay leaned.

..
Center-stand is offline   Reply With Quote
Old 07-11-2013, 07:52 PM   #789
Rucksta
Chronic Noob
 
Rucksta's Avatar
 
Joined: Oct 2008
Location: Gold Coast
Oddometer: 2,568
Quote:
Originally Posted by Center-stand View Post
.



Too many variables. Who's holding your beer?

..
I find if I have to get someone to hold my beer - the worst case (most entertaining) scenario is the usual result
__________________
My bike is slow but the earth is patient.
Rucksta is offline   Reply With Quote
Old 07-11-2013, 08:11 PM   #790
Rucksta
Chronic Noob
 
Rucksta's Avatar
 
Joined: Oct 2008
Location: Gold Coast
Oddometer: 2,568
Quote:
Originally Posted by SkiFastBadly View Post
You'll go straight...without a front tire contacting the ground you are at the mercy of Newton's first law.
Quote:
  1. First law: When viewed in an inertial reference frame, an object either is at rest or moves at a constant velocity, unless acted upon by a force.[2][3] Wiki

This makes me wonder if there is a "virtual" point of contact when the front wheel is off the ground providing the "force"
The bike will turn on one wheel.
Turning the bars will affect the lean angle (if the front wheel is still spinning)
The out-tracking behaviour is apparent if somwhat magnified like extended forks give but without the increase in trail.
__________________
My bike is slow but the earth is patient.
Rucksta is offline   Reply With Quote
Old 07-12-2013, 04:44 AM   #791
Center-stand
Gnarly Adventurer
 
Joined: Nov 2008
Oddometer: 386
..

Rucksta, maybe something in this will answer your questions.


http://www.darkroastedblend.com/2008...-known-to.html

..
Center-stand is offline   Reply With Quote
Old 07-12-2013, 08:55 AM   #792
Rucksta
Chronic Noob
 
Rucksta's Avatar
 
Joined: Oct 2008
Location: Gold Coast
Oddometer: 2,568
Quote:
Originally Posted by Center-stand View Post
..

Rucksta, maybe something in this will answer your questions.


http://www.darkroastedblend.com/2008...-known-to.html

..

Not really - the article is light weight on the details of steeering but thanks for the read.
We already knew a bike could turn on one wheel from the video of the stunt rider.
The value I took from it was inventors have been engaged by how mono track and mono wheel vehicles turn or don't turn for quite some time.
Some, like their creations, and this thread keep going round in circles.

I'm not actually looking for an answer as I'm happy to accept my motorcycle turns if I do this thing or that thing or even some other thing.
If you could come up with yet another thing I would be happy to listen and try it even if the idea sounded somewhat implausable.
Push left to go left would have sounded implausable to many hearing it for the first time.

If I could ask the questions that challenged some of the devout, polarised views of the one true way to turn a motorcycle it would please me.
__________________
My bike is slow but the earth is patient.
Rucksta is offline   Reply With Quote
Old 07-13-2013, 12:13 AM   #793
Center-stand
Gnarly Adventurer
 
Joined: Nov 2008
Oddometer: 386
..

Not sure how, but in my mind this fits here. It is a wheel going round, ....and round and round.

http://screen.yahoo.com/man-hula-hoo...112816079.html

..
Center-stand is offline   Reply With Quote
Old 07-13-2013, 08:34 AM   #794
lnewqban
Ninjetter
 
lnewqban's Avatar
 
Joined: Jan 2012
Location: Florida
Oddometer: 290
Cool2

For those who don't care or don't get counter-steering, just try balancing via steering:



lnewqban is offline   Reply With Quote
Old 08-07-2013, 01:19 PM   #795
Seth650
Gnarly Adventurer
 
Seth650's Avatar
 
Joined: Sep 2012
Location: N. E. Pa.
Oddometer: 382
I do countersteering on poor quality pavement (greasy and dirt-strewn), and often off-road.

In a turn:

1. non-countersteer - lean with bike:

pro's
not tedious on twisties.
easier to learn.

con's
g-forces add side-weight to contact patch(es).
rider less reactive to unexpected obstacle.

2. countersteer - stay upright with only bike leaned (including partial stand-on-pegs):

pro's
g-forces don't add as much side-weight to contact patch(es), as rider g-force is straight not sidways, with more weight on front wheel when on pegs.

more reactive for swerving.

con's
tedious on twisties.
requires additional practice to do safely.
__________________
2011 WR250R 2009 DR650
Seth650 is offline   Reply With Quote
Reply

Share

Thread Tools Search this Thread
Search this Thread:

.
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On

Forum Jump


Times are GMT -7.   It's 06:10 PM.


Powered by vBulletin® Version 3.8.5
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Copyright ADVrider 2011-2014