The lowsider or lowside is a type of

motorcycle A motorcycle (motorbike, bike, or trike (if three-wheeled)) is a two or three-wheeled motor vehicle Steering, steered by a Motorcycle handlebar, handlebar. Motorcycle design varies greatly to suit a range of different purposes: Long-distance ...

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crash Crash or CRASH may refer to: Common meanings * Collision, an impact between two or more objects * Crash (computing), a condition where a program ceases to respond * Cardiac arrest, a medical condition in which the heart stops beating * Couch ...

usually occurring in a turn. It is caused when either the front or rear wheel slides out as a result of either too much

braking A brake is a mechanical device that inhibits motion by absorbing energy from a moving system. It is used for slowing or stopping a moving vehicle, wheel, axle, or to prevent its motion, most often accomplished by means of friction. Backgroun ...

into the corner, too much acceleration through or out of the corner, or too much speed carried into or through the corner for the available grip. It may also be caused by unexpected slippery or loose material (such as oil, water, dirt or gravel) on the road surface. In the

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and

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it is referred to as a "lowside" rather than a "lowsider".

Causes of lowsider crashes

All horizontal

force In physics, a force is an influence that can change the motion of an object. A force can cause an object with mass to change its velocity (e.g. moving from a state of rest), i.e., to accelerate. Force can also be described intuitively as a ...

s occurring between the motorcycle and the road (such as accelerating, decelerating and steering) are transmitted by

friction Friction is the force resisting the relative motion of solid surfaces, fluid layers, and material elements sliding against each other. There are several types of friction: *Dry friction is a force that opposes the relative lateral motion of ...

in the

contact patch Contact patch is the portion of a vehicle's tire that is in actual contact with the road surface. It is commonly used in the discussion of pneumatic (i.e. pressurized) tires, where the term is used strictly to describe the portion of the tire’s ...

es. There is a limited amount of force each contact patch can transmit before the tire begins to slide. Typically, the maximum force once sliding is slightly less than before sliding."Tire and Vehicle Dynamics", Hans B Pacejka When travelling in a curve, the tires provide the

centripetal force A centripetal force (from Latin ''centrum'', "center" and ''petere'', "to seek") is a force that makes a body follow a curved path. Its direction is always orthogonal to the motion of the body and towards the fixed point of the instantaneous c ...

needed for the acceleration towards the center of the curve. The capsizing

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provided by gravity acting on the motorcycle center of mass when leaning into a corner is balanced by a righting moment generated by centripetal forces in the contact patches when all is working correctly. If, having reached a given lean angle, the centripetal forces are reduced then the motorcycle increases its angle of lean until it touches the road surface, usually unseating the rider in the process. Lowsiders are caused by exceeding the lateral friction limit or by exceeding the combined lateral/longitudinal friction limit in one or more of the following ways: * Braking force plus turning force exceeds friction available on either tire * Turning forces exceed friction available on either tire * Acceleration force exceeds friction on the rear tire * Bodywork or peg hitting a road surface lifts the bike causing less friction on either wheel * Rapid deflation of one of the tires causes grip levels to reduce Lowsider crashes are not usually caused by braking in a straight line in dry conditions. It is more likely that the rider will go over the handlebars through too much front wheel brake force or will lock the rear wheel resulting in a straight skid. The name derives from the fact that it is the low side of the motorcycle that hits the ground.

Injury risks

Riders are usually advised to do a lowsider rather than a

highsider A highsider or highside is a type of motorcycle accident characterized by sudden and violent rotation of the bike around its long axis. This generally happens when the rear wheel loses traction, skids, and then suddenly regains traction, creating ...

if neither can be avoided. The lowsider has the advantage of the motorcycle sliding before the rider, thus not threatening to crush them. Also, a lowsider tends to send the rider sliding across the road whereas a highsider is considered more severe as it violently throws the rider from the motorcycle with a higher probability of broken bones. The main injury risks are: * Gravel rash due to sliding across the road surface at speed * Hitting traffic coming in the opposing lane * Impact injuries on the side the rider goes down (usually an elbow, shoulder or hip

contusion A bruise, also known as a contusion, is a type of hematoma of tissue, the most common cause being capillaries damaged by trauma, causing localized bleeding that extravasates into the surrounding interstitial tissues. Most bruises occur clos ...

, but the bike landing on an ankle can cause injuries, too) * Hitting static objects on the side of the road such as

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or signage

References

{{reflist Motorcycle dynamics Road accidents and incidents

Causes of lowsider crashes

Injury risks

See also

References