Lowsider
From Wikipedia, the free encyclopedia
The lowsider or lowside is a type of motorcycle accident usually occurring in a curve and caused by a locked wheel due to excessive braking.
[edit] Behaviour leading to a lowsider and physical explanation
All forces occurring between the motorcycle and the road (such as accelerating, decelerating and steering) are transmitted by friction occurring in the contact patch. There is a limited amount of force the contact patch can transmit before the tire begins to slide.
If the driver makes a curve on a motorcycle, the driver applies a force on the motorcycle, causing it to alter its course. This force is transferred to the motorcycle through the contact patch. Braking within a curve will increase the stress in the contact patch, because now there is an additional force which also has to be transmitted through the contact patch. This additional amount of force may cause the tire to slide and lock. If braking is applied equally to both tires, the rear tire will begin to slide first because braking causes a weight shift towards the front tire, improving its contact with the road while lessening the rear tire's grip.
Once a tire slips in a curve, it will move outwards under the motorcycle and cause the cycle to lay down in the direction the driver is already leaning to counteract the centrifugal force. Unless this movement is counteracted, the motorcycle will lay down and slide outwards. Counteracting this movement by reducing brake force may lead to a highsider.
The name derives from the fact that it is usually the inward side the motorcycle will fall on (or the side that points downward in a curve, the low side).
Drivers are usually advised to do a lowsider rather than a highsider if neither can be avoided. The lowsider has the advantage of the motorcycle sliding before the driver, thus not threatening to crush him.
