What Is High Siding A Motorcycle And What Causes It?

High siding is a type of motorcycle crash where the bike’s rear tire loses traction, then suddenly regains it, snapping the motorcycle upright and throwing the rider over the top. The rider often gets launched into the air before the bike itself. It is widely considered more dangerous than a low side, where the bike simply slides out from under the rider.

The term comes from the direction the rider travels. In a low side, the bike falls to the inside of the turn and the rider goes down with it. In a high side, the bike whips to the outside of the turn and the rider is flung over the high side of the seat. The physics behind it are well understood. The outcome for the rider is often worse.

What Is High Siding A Motorcycle And What Causes It?

A high side happens when the rear tire breaks traction and then grips again while the bike is still moving and leaned over. That sudden return of grip is the problem. The rear wheel stops sliding sideways and catches the pavement, but the motorcycle is still carrying forward momentum and is still at a lean angle. The energy has nowhere to go except up.

The sequence usually looks like this:

• The rider accelerates too hard, brakes too abruptly, or hits a slick patch, and the rear tire loses grip.
• The rear of the bike slides out sideways, often to the outside of the turn.
• The rider instinctively rolls off the throttle or the tire finds clean pavement, and traction returns.
• The rear tire catches, the bike snaps upright violently, and the rider is thrown over the handlebars or over the high side of the seat.

The snapping motion is the key. It is not a gradual loss of control. It is a sudden transfer of force that the rider cannot physically counter in time. This is why high sides are often described as the most violent type of motorcycle crash.

Why Does The Rear Tire Lose Grip In The First Place?

Traction loss at the rear wheel almost always comes down to one of a few conditions. Too much throttle for the available grip is the most common cause. When a rider opens the throttle hard while leaned over, the rear tire can spin faster than the bike is moving. That is called wheelspin, and it means the tire has broken free of the road surface.

Cold tires are another factor. Tire rubber needs to reach operating temperature to provide maximum grip. A tire that has not warmed up offers less traction, so the same throttle input that would be fine on a warm tire can break the rear loose on a cold one. This is part of why crashes are more common in the first few minutes of a ride.

Wet or contaminated pavement reduces grip dramatically. Oil, antifreeze, sand, painted road markings, and metal surfaces like manhole covers all offer far less traction than dry asphalt. A rider who does not adjust throttle and lean angle for these conditions is at higher risk.

Abrupt braking can also cause the rear to slide. Hard rear brake application can lock the rear wheel, and a locked wheel provides almost no directional grip. Some riders also downshift too aggressively, which can cause the rear tire to lose traction through engine braking alone.

Why Is A High Side More Dangerous Than A Low Side?

In a low side, the bike and rider slide along the ground together. The rider stays relatively close to the pavement and the impact forces are spread across the slide. Protective gear is designed to handle this kind of contact. Road rash and broken bones are common, but the mechanism is more forgiving.

A high side is different in almost every way. The rider is thrown upward and often forward, which means a longer fall and a harder landing. The bike may also tumble and follow the rider, creating a risk of being struck by the motorcycle itself. Impact speeds at the moment of landing can be high because the rider has been launched rather than simply dropped.

The body position at impact also matters. A rider thrown over the top is often tumbling and unable to control how they land. Head, neck, and spinal injuries are more likely in this scenario. This is why high sides are treated as a distinct and more serious category of crash.

What Role Does Rider Input Play In A High Side?

Rider reaction is often the trigger that turns a slide into a high side. When the rear tire steps out, the natural instinct is to chop the throttle. That instinct is understandable, but it is also what causes the tire to regain grip suddenly. A gradual, controlled reduction of throttle gives the tire a chance to regain traction more smoothly.

Experienced riders are often taught to stay smooth on the controls when the rear slides. That does not mean the slide is always recoverable. Sometimes the slide is too far gone, or the surface is too unpredictable. But the difference between a slide that recovers and one that becomes a high side often comes down to how abruptly the rider reacts.

This is one reason rider training programs emphasize smooth inputs. Throttle, brake, and steering inputs that are applied gradually give the tires time to communicate with the road. Abrupt inputs overwhelm the available grip. The physics are not complicated, but the human instinct under stress is hard to override.

Can A High Side Be Prevented?

Some high sides are preventable, and some are not. The most effective prevention is managing traction before it is lost. That means respecting cold tires, reducing lean angle and throttle in wet conditions, and avoiding abrupt control inputs when the bike is leaned over.

Tire condition matters more than many riders realize. Tread depth, tire age, and inflation pressure all affect how much grip is available. A tire that is underinflated, overinflated, or worn past its useful life offers less traction than a properly maintained one. Checking tire pressure before a ride is a basic step that has a real effect on grip.

Traction control systems on modern motorcycles can help in some situations. These systems detect rear wheel spin and reduce power to help the tire regain grip. They are not a substitute for good riding technique, and they do not prevent every high side. But they can reduce the likelihood of a rear tire breaking loose under hard acceleration.

Rider training also plays a role. Courses that teach throttle control, braking technique, and cornering fundamentals help riders build the habits that reduce risk. No amount of training makes a rider immune to a high side, but it does change how a rider responds when the rear tire starts to slide.

What Should A Rider Do If The Rear Tire Starts To Slide?

The general guidance is to stay smooth and avoid sudden inputs. If the rear tire steps out, the goal is to let it regain traction gradually rather than forcing it to catch all at once. That usually means maintaining steady throttle or reducing it slowly, keeping the bike as stable as possible.

This is easier to describe than to do. Under stress, the body wants to react quickly. Riders who have practiced slide recovery in a controlled environment, such as a track or a training course, are often better prepared to respond calmly. That practice does not guarantee a good outcome, but it improves the odds.

If a high side does happen, protective gear is the last line of defense. A full-face helmet, armored jacket, gloves, and boots are designed to reduce injury in a crash. They cannot prevent all injuries, especially in a high-energy impact, but they are the difference between a survivable crash and a catastrophic one in many cases.