and normal forces. There is a limited amount of force tangential to the road that the contact patch can transmit before the tire begins to lose traction, and therefore slide or skid. When going through a curve on a motorcycle, centripetal force (added to the other lateral forces such as acceleration or deceleration) is transferred from the road to the motorcycle through the contact patch, and is directed at a right angle to the path of travel. If the net force is greater than the static friction coefficient of the tire multiplied by the normal force of the motorcycle through the tire, the tire will skid outwards from the direction of the curve. Once a tire slips in a curve, it will move outwards under the motorcycle. What happens from there depends on how well the rider is able to restore balance and control. If the tire regains traction after the rider starts to skid while the motorcycle is moving sideways, the tire will stop its sideways movement causing the motorcycle to suddenly jerk into an upright position (and beyond). This movement can easily cause the rider to be thrown off. Injury risks The term highside derives from the side of the motorcycle where the rider separates from it. If forcibly thrown over the bike, the rider is said to have dismounted on the high side. The violent motion of the motorbike usually throws the rider several feet into the air which can result in broken bones on impact with the road surface. As the highside catches the rider unexpectedly, the rider's limbs can be thrown into protrusions on the bike (usually the handlebars) and suffer contusions. The rider is thrown ahead of the bike and is at risk of being hit and seriously injured by the bike, particularly if the rider stops quickly. Because highsider accidents are so much more deadly than lowside accidents, the Motorcycle Safety Foundation recommends that if a rider locks the rear brake at higher speeds and the traction is good, the brake should not be released. See also Bicycle and motorcycle dynamics Lowsider Motorcycle safety References Road accidents and incidents Motorcycle dynamics