HIGH SIDE DYNAMICS
This article discusses some of the details of motorcycling that may be discussed briefly in a safety course.
Making a mistake while riding a motorcycle can lead to some kind of consequence, sometimes just surface abrasions on yourself and your motorcycle, sometimes more serious injuries and sometimes it can even be FATAL!
One of the more serious mistakes of riding a motorcycle, is unconciously contributing to a HIGH SIDE.
When a bike is "dropped" or "dumped" or "laid down", it falls down due to gravity assistance and ends up sliding on its side. At slower speeds it results in little damage to the bike or rider, when the rider is adequately protected with proper riding gear and a good helmet. The term "LOW SIDE" refers to the more common way of encountering some trouble while riding a bike, where the rider is removed from controlling the bike and (usually) goes in the direction as the bike -> 'down'. Thankfully, this type of situation is generally survivable.
A HIGH SIDE, on the other hand, means that you are FORCIBLY REMOVED by being thrown UP and OVER the 'high side of the bike'. The bike then can follow the rider into the air, and then back down (and possible ON TOP of the rider!) Not too many people survive this kind of encounter!
How does a HIGH SIDE happen and what can you do to prevent it?
A HIGH SIDE starts when you use TOO MUCH REAR BRAKE PRESSURE, LOCKING the REAR WHEEL. This causes the rear of the bike to slide out away from the direction that the bike has been moving, because all the traction has been lost from the rear tire. The rear wheel, in fact has now begun to MOVE FASTER than the front tire, centrifugal forces tend to come into play here as well.
The correct response would be to turn the front wheel in the direction of the slide, but if the REAR BRAKE is released in the process, it leads to a serious mistake which will comprimise any attempt to correct the skid.
Normally the rear wheel tracks the front. When the rear brake locks, the rear wheel loses traction, then begins to slide OUTWARD from the center of a curve. As the rider turns the front wheel in the same direction as the skid, the direction of the bike is now changed. Meanwhile the rear end of the bike continues to slide and is now MOVING FASTER than the front end of the bike at this instance. This is sometimes referred to as 'sliding out'. If left alone, the bike will try to 'lay itself down'.
However, if rider realizes that the rear end of his bike is sliding completely out of control and decides to correct by releasing the rear brake to 'ride out of the situation' .....the rear tire begins to turn again. It now can move easier in the forward direction than before, as it regains traction. The bike is now moving FASTER in the direction pointed by the front tire. At the same time, the inertia forces imparted by the rear end, coupled with the abrupt stopping of rear wheel sliding comes into play because forward momentum energy will be imparted on the suspension parts which are generally springs to store and release energy, with some oil damping.
Centrifugal force, coupled with inertia try to keep the bike's TOP SIDE moving in the direction it was last travelling. Since the bottom of of the rear wheel has stopped sliding, this results in the bike being VIOLENTLY TWISTED in the direction of the earlier slide. The front wheel helps this twisting action because of the bearing located on the front axle. This will cause the bike to ROTATE UP, using the front axle as a pivot point. The rider will be thrown off the bike in the same direction as it is being twisted. (Analogous to being in a rodeo on a bucking bronco and being thrown off the horse).
The mistake, of course is to release the pressure on the rear brake. Should you be confronted with a point of no return, with the rear wheel locked up while the rear of the bike is coming around, the safest course of of action is probably to STAY WITH THE BIKE and RIDE IT INTO THE GROUND by doing a LOW SIDE.
Now you should be asking this question.."Can a HIGH-SIDE occur if you do not release the rear brake pressure at all?" If you were ever to witness a 'straight line' high side accident, you would observe that the skid mark was straight.... until it ended with a 'J'. This would mean that the rider successfully kept his bike pointed in the direction of the skid until he had turned the front wheel to its limits and hit the 'stops'. At that point the bike direction abruptly changed, and the skid increased until it represented a 90 degree tire orientation the direction the bike is moving. This point would have presented the maximum traction point. At this point the bike stops its skidding, and VIOLENTLY SNAPS into air.
What could you do if you had a choice in the situation at hand?
As soon as you know that YOUR EFFORTS are not going to PREVENT A HIGH SIDE and the situation is fast appoaching where you KNOW you have lost complete control....
GRAB THAT FRONT BRAKE AS HARD AS YOU CAN and FORCE A LOW-SIDE!
You have a much better chance of survival, with minimal or less serious injuries with a low side by laying it down. This doesn't imply that you should use this technique to avoid proper emergency braking, BUT if there is NO OTHER CHOICE, it is better to 'sacrifice' the bike in order to keep yourself from getting major damage.
Courtesy of http://www.bikersdown.net
This article discusses some of the details of motorcycling that may be discussed briefly in a safety course.
Making a mistake while riding a motorcycle can lead to some kind of consequence, sometimes just surface abrasions on yourself and your motorcycle, sometimes more serious injuries and sometimes it can even be FATAL!
One of the more serious mistakes of riding a motorcycle, is unconciously contributing to a HIGH SIDE.
When a bike is "dropped" or "dumped" or "laid down", it falls down due to gravity assistance and ends up sliding on its side. At slower speeds it results in little damage to the bike or rider, when the rider is adequately protected with proper riding gear and a good helmet. The term "LOW SIDE" refers to the more common way of encountering some trouble while riding a bike, where the rider is removed from controlling the bike and (usually) goes in the direction as the bike -> 'down'. Thankfully, this type of situation is generally survivable.
A HIGH SIDE, on the other hand, means that you are FORCIBLY REMOVED by being thrown UP and OVER the 'high side of the bike'. The bike then can follow the rider into the air, and then back down (and possible ON TOP of the rider!) Not too many people survive this kind of encounter!
How does a HIGH SIDE happen and what can you do to prevent it?
A HIGH SIDE starts when you use TOO MUCH REAR BRAKE PRESSURE, LOCKING the REAR WHEEL. This causes the rear of the bike to slide out away from the direction that the bike has been moving, because all the traction has been lost from the rear tire. The rear wheel, in fact has now begun to MOVE FASTER than the front tire, centrifugal forces tend to come into play here as well.
The correct response would be to turn the front wheel in the direction of the slide, but if the REAR BRAKE is released in the process, it leads to a serious mistake which will comprimise any attempt to correct the skid.
Normally the rear wheel tracks the front. When the rear brake locks, the rear wheel loses traction, then begins to slide OUTWARD from the center of a curve. As the rider turns the front wheel in the same direction as the skid, the direction of the bike is now changed. Meanwhile the rear end of the bike continues to slide and is now MOVING FASTER than the front end of the bike at this instance. This is sometimes referred to as 'sliding out'. If left alone, the bike will try to 'lay itself down'.
However, if rider realizes that the rear end of his bike is sliding completely out of control and decides to correct by releasing the rear brake to 'ride out of the situation' .....the rear tire begins to turn again. It now can move easier in the forward direction than before, as it regains traction. The bike is now moving FASTER in the direction pointed by the front tire. At the same time, the inertia forces imparted by the rear end, coupled with the abrupt stopping of rear wheel sliding comes into play because forward momentum energy will be imparted on the suspension parts which are generally springs to store and release energy, with some oil damping.
Centrifugal force, coupled with inertia try to keep the bike's TOP SIDE moving in the direction it was last travelling. Since the bottom of of the rear wheel has stopped sliding, this results in the bike being VIOLENTLY TWISTED in the direction of the earlier slide. The front wheel helps this twisting action because of the bearing located on the front axle. This will cause the bike to ROTATE UP, using the front axle as a pivot point. The rider will be thrown off the bike in the same direction as it is being twisted. (Analogous to being in a rodeo on a bucking bronco and being thrown off the horse).
The mistake, of course is to release the pressure on the rear brake. Should you be confronted with a point of no return, with the rear wheel locked up while the rear of the bike is coming around, the safest course of of action is probably to STAY WITH THE BIKE and RIDE IT INTO THE GROUND by doing a LOW SIDE.
Now you should be asking this question.."Can a HIGH-SIDE occur if you do not release the rear brake pressure at all?" If you were ever to witness a 'straight line' high side accident, you would observe that the skid mark was straight.... until it ended with a 'J'. This would mean that the rider successfully kept his bike pointed in the direction of the skid until he had turned the front wheel to its limits and hit the 'stops'. At that point the bike direction abruptly changed, and the skid increased until it represented a 90 degree tire orientation the direction the bike is moving. This point would have presented the maximum traction point. At this point the bike stops its skidding, and VIOLENTLY SNAPS into air.
What could you do if you had a choice in the situation at hand?
As soon as you know that YOUR EFFORTS are not going to PREVENT A HIGH SIDE and the situation is fast appoaching where you KNOW you have lost complete control....
GRAB THAT FRONT BRAKE AS HARD AS YOU CAN and FORCE A LOW-SIDE!
You have a much better chance of survival, with minimal or less serious injuries with a low side by laying it down. This doesn't imply that you should use this technique to avoid proper emergency braking, BUT if there is NO OTHER CHOICE, it is better to 'sacrifice' the bike in order to keep yourself from getting major damage.
Courtesy of http://www.bikersdown.net
