02-07-2016, 03:01 PM
Intrigued by Riko’s post I have done some research on this subject. Rather than broadcast my own rather amateurish opinions, I consulted Keith Code’s “A Twist of the Wrist II: The Basics of High Performance Motorcycling.
‘Who is Keith Code?’, you may ask. Keith Code is a former motorcycle racer, writer, and founder of the California Superbike School. He has been called "arguably the best known and most successful on-track motorcycle instructor in the world”. He knows a little bit more about riding technique than me (insert irony smilie here). I would recommend his book to anyone, regardless of skill level. Never too smart to stop learning and never to late to visit things long forgotten. Let me quote, in part, from Chapter Eight, Rider Input - Holding On:
“…, The overwhelming choice for runner-up in the “unwanted riding conditions” class is: TOO TIGHT ON THE BARS. The same triggers [Code calls them Survival Reactions, or SRs] that cause roll-off/roll-on also fire up this unconscious action. ……"
Continuing, Code says:
"My first inclination is to simply say “relax on the bike”, but because we’re dealing with SRs, it’s not that easy. If there was a way to simply hot-wire (by pass) these reactions, I’d tell you, but there isn’t. But we can handle them, using education as our primary tool. So let’s get smart about holding on.
Machine Demands
Depending on road surface conditions, speed, tires and suspension your bike will head shake, a little or a lot, with some combination of these influences. Any bike will do it. What most riders fail to realise is that this shake is a necessary part of the bike’s suspension system. This system has two stages we can see right away, (1) the tire, and (2) the shocks and forks. The tire handles some of the road’s imperfections because it is rubber and flexes. When it reaches the limit of it’s flex, the shock and fork take over to stabilise the bike. What happens when these two systems fail to handle the situation? The forks move, side to side. They are the next thing to move and they do.
When (1) and (2) above have reached their limits, the immediate result is weight changes to the tires: heavy/light, light/heavy. A spread-out contact patch (when weighting is heavy) forces the forks to turn inwards. When weighting lightens up, the forks seek to return to the centred or neutral position, to track for the lean angle you have. The fork doesn’t quite stop at the perfect tracking position, it goes slightly past it. By this time the tire has hit at least one more surface imperfection and is going through the light/heavy phase again, spreading the contact patch and turning it inwards. That’s what shakes the head.
Stop Shaking
No one is strong enough to stop this from happening. In fact, if you did stop it, the bike would instantly wobble violently and be totally out of control. [My italics.] The good news is that if your bike is basically tight (steering-head bearings not excessively worn, forks and shocks not sticking etc,) the head shake stays up front and does not transfer to the rest of the bike. The bad news is that these head shakes are transferred, back through the rider, after SR#2 [holding on too tight] has kicked in.
………. Hold tight and the bike feels totally unstable and ready to crash; loosen up and it goes straight, even though the front end is working [sometimes imperceptibly] back and forth.”
Code then goes on to explain why holding on tight causes the bike to run wide in turns. Interesting stuff. But back to the wobbles. Code again (his bold):
“….. If everything is tight and your steering damper (if fitted) is working correctly, it only gets as bad as you hold it tight! Remember to relax. Overcoming the “too tight” SR is the hard part. Allowing the front end to “work” is a standard riding technique which agrees with machine design.
Too tight on the bars is the most common source of motorcycle handling problems.”
Donny Greene, five times US 250 GP Champion, comments at the end of the chapter:
“Bending the elbows and wrists instead of straight-arming the bike will set you up to be in a more friendly and relaxed position on the bike. I only vary my grip when I’m making steering changes. Outside of that , my grip is equal and relaxed as I can make it. Treat the bike like a friend and it won’t work against you”
The advice Code and Greene give is real world stuff. When I’m into a long section of twisties and a few of my lines are not what I would want I deliberately loosen up on the bars and ensure that my inside push to counter-steer is only inside of the knuckles, light but positive. Before I apply any counter steer force I consciously relax my outside hand to the point of almost no contact if it is the left and just enough for throttle control with the right. Grip with the knees, eyes on the extended line (look through the corner), weight on the balls of the feet, and lo and behold, problem fixed. Mostly habit for me but if I'm a bit tired or tense for any reason, it has to be done deliberately.
You may have the impression that Code’s book is biased towards the track, and I have to say it is, even though the techniques described therein do translate to the street rider. A good read that is very applicable to street riding is Lee Parks’ Total Control: High Performance Street Riding Techniques. Some say he “unlocks the Code”. He discusses at length a relaxed grip, steering with the inside arm only, and steering “weave”. He says:
“As a motorcycle travels down the road, it actually moves in a nearly undetectable low-amplitude weave, even when the rider thinks it is going straight. ……..”.
“It is my ardent belief that when cornering, you should only use your inside arm to steer. This includes both pushing and pulling when appropriate. ……”
So there it is. Straight from the horses mouth, so to speak. Steering wobble - it’s always there. Good bike condition and a proper riding technique make it our friend.
Both these books are available on internet order in both hard and soft copy. Some forum members have read them. Once again, if you think you would benefit then some schooling at a reputable and appropriate place (Both Parks and Code run schools), and a bit of reading are invaluable tools in the armoury of the serious and safe motorcyclist. I’m a bit long in the tooth (despite my own advice) for track days and try to survive on the road by sheer rat cunning and the occasional glance at Parks and Code. Otherwise I'd enjoy a day at the California Superbike School chasing Ride4now (see [url=http://cb1100forum.com/forum/showthread.php?tid=7938&highlight=california]his thread) and checking out all that California talent.
Cheers all.
‘Who is Keith Code?’, you may ask. Keith Code is a former motorcycle racer, writer, and founder of the California Superbike School. He has been called "arguably the best known and most successful on-track motorcycle instructor in the world”. He knows a little bit more about riding technique than me (insert irony smilie here). I would recommend his book to anyone, regardless of skill level. Never too smart to stop learning and never to late to visit things long forgotten. Let me quote, in part, from Chapter Eight, Rider Input - Holding On:
“…, The overwhelming choice for runner-up in the “unwanted riding conditions” class is: TOO TIGHT ON THE BARS. The same triggers [Code calls them Survival Reactions, or SRs] that cause roll-off/roll-on also fire up this unconscious action. ……"
Continuing, Code says:
"My first inclination is to simply say “relax on the bike”, but because we’re dealing with SRs, it’s not that easy. If there was a way to simply hot-wire (by pass) these reactions, I’d tell you, but there isn’t. But we can handle them, using education as our primary tool. So let’s get smart about holding on.
Machine Demands
Depending on road surface conditions, speed, tires and suspension your bike will head shake, a little or a lot, with some combination of these influences. Any bike will do it. What most riders fail to realise is that this shake is a necessary part of the bike’s suspension system. This system has two stages we can see right away, (1) the tire, and (2) the shocks and forks. The tire handles some of the road’s imperfections because it is rubber and flexes. When it reaches the limit of it’s flex, the shock and fork take over to stabilise the bike. What happens when these two systems fail to handle the situation? The forks move, side to side. They are the next thing to move and they do.
When (1) and (2) above have reached their limits, the immediate result is weight changes to the tires: heavy/light, light/heavy. A spread-out contact patch (when weighting is heavy) forces the forks to turn inwards. When weighting lightens up, the forks seek to return to the centred or neutral position, to track for the lean angle you have. The fork doesn’t quite stop at the perfect tracking position, it goes slightly past it. By this time the tire has hit at least one more surface imperfection and is going through the light/heavy phase again, spreading the contact patch and turning it inwards. That’s what shakes the head.
Stop Shaking
No one is strong enough to stop this from happening. In fact, if you did stop it, the bike would instantly wobble violently and be totally out of control. [My italics.] The good news is that if your bike is basically tight (steering-head bearings not excessively worn, forks and shocks not sticking etc,) the head shake stays up front and does not transfer to the rest of the bike. The bad news is that these head shakes are transferred, back through the rider, after SR#2 [holding on too tight] has kicked in.
………. Hold tight and the bike feels totally unstable and ready to crash; loosen up and it goes straight, even though the front end is working [sometimes imperceptibly] back and forth.”
Code then goes on to explain why holding on tight causes the bike to run wide in turns. Interesting stuff. But back to the wobbles. Code again (his bold):
“….. If everything is tight and your steering damper (if fitted) is working correctly, it only gets as bad as you hold it tight! Remember to relax. Overcoming the “too tight” SR is the hard part. Allowing the front end to “work” is a standard riding technique which agrees with machine design.
Too tight on the bars is the most common source of motorcycle handling problems.”
Donny Greene, five times US 250 GP Champion, comments at the end of the chapter:
“Bending the elbows and wrists instead of straight-arming the bike will set you up to be in a more friendly and relaxed position on the bike. I only vary my grip when I’m making steering changes. Outside of that , my grip is equal and relaxed as I can make it. Treat the bike like a friend and it won’t work against you”
The advice Code and Greene give is real world stuff. When I’m into a long section of twisties and a few of my lines are not what I would want I deliberately loosen up on the bars and ensure that my inside push to counter-steer is only inside of the knuckles, light but positive. Before I apply any counter steer force I consciously relax my outside hand to the point of almost no contact if it is the left and just enough for throttle control with the right. Grip with the knees, eyes on the extended line (look through the corner), weight on the balls of the feet, and lo and behold, problem fixed. Mostly habit for me but if I'm a bit tired or tense for any reason, it has to be done deliberately.
You may have the impression that Code’s book is biased towards the track, and I have to say it is, even though the techniques described therein do translate to the street rider. A good read that is very applicable to street riding is Lee Parks’ Total Control: High Performance Street Riding Techniques. Some say he “unlocks the Code”. He discusses at length a relaxed grip, steering with the inside arm only, and steering “weave”. He says:
“As a motorcycle travels down the road, it actually moves in a nearly undetectable low-amplitude weave, even when the rider thinks it is going straight. ……..”.
“It is my ardent belief that when cornering, you should only use your inside arm to steer. This includes both pushing and pulling when appropriate. ……”
So there it is. Straight from the horses mouth, so to speak. Steering wobble - it’s always there. Good bike condition and a proper riding technique make it our friend.
Both these books are available on internet order in both hard and soft copy. Some forum members have read them. Once again, if you think you would benefit then some schooling at a reputable and appropriate place (Both Parks and Code run schools), and a bit of reading are invaluable tools in the armoury of the serious and safe motorcyclist. I’m a bit long in the tooth (despite my own advice) for track days and try to survive on the road by sheer rat cunning and the occasional glance at Parks and Code. Otherwise I'd enjoy a day at the California Superbike School chasing Ride4now (see [url=http://cb1100forum.com/forum/showthread.php?tid=7938&highlight=california]his thread) and checking out all that California talent.
Cheers all.
