A high side is a type of motorcycle crash where the rear wheel loses traction, then suddenly regains it, violently flipping the bike toward the outside of a turn and launching the rider into the air. It’s widely considered the most dangerous kind of single-vehicle motorcycle crash, and nearly all high sides are triggered by something the rider does mid-corner.
How a High Side Happens
The sequence starts when the rear tire breaks loose while you’re leaned into a curve. This can happen because you hit the rear brake too hard and lock the wheel, or because you cracked the throttle too aggressively and spun the tire. Either way, the rear end starts sliding out of alignment with the front tire.
Here’s where instinct becomes the enemy. When the rear steps out, most riders reflexively release the brake or chop the throttle. The moment that happens, the rear tire suddenly grips the pavement again. But the wheel is now pointed in a different direction than the bike is traveling. All that rotational energy snaps the rear end back in line with the front, and the bike whips upright with enormous force. The motorcycle essentially catapults the rider up and over the high side of the bike, toward the outside of the turn.
Riders have been launched 33 to 54 feet through the air in documented high side crashes. Video analysis of real incidents shows riders landing in bizarre orientations: seated but facing backward, or prone with feet leading. The violence of the launch is what separates a high side from every other type of motorcycle fall.
High Side vs. Low Side
A low side is the opposite scenario. The tire loses traction and the bike simply slides down toward the inside of the turn. The rider goes down with it, relatively close to the ground, and both bike and rider slide along the pavement. It’s still a crash, but the forces involved are dramatically lower.
A study of 78 crashes in MotoGP, professional motorcycle racing’s top class, put hard numbers on the difference. Of 58 low side crashes, only one resulted in a significant injury, and none required emergency transport. Of 13 high side crashes, seven produced significant injuries, nine riders needed emergency transport to a medical facility, and three were admitted to a hospital. Roughly 77% of riders who high-sided retired from the race, compared to about 33% after a low side. These are elite riders wearing the best protective gear available, crashing on tracks designed with runoff zones. On public roads, the gap in severity is even wider.
The key distinction is trajectory. In a low side, you slide. In a high side, you fly. The bike launches you upward and forward, then you hit the ground and decelerate at roughly 1g as you tumble and slide to a stop. You also risk the motorcycle landing on top of you or striking you as it tumbles separately along its own path.
The Two Triggers
Locking the Rear Brake in a Turn
If you apply too much rear brake while leaned over in a curve, the rear tire locks and begins to skid. The back of the bike slides outward. If you keep the brake locked, the bike will low side, which is bad but survivable. The critical mistake is releasing the brake once the rear has already swung out. The tire instantly regains grip, snaps the rear back into alignment, and you’re airborne.
Spinning the Rear Tire With Throttle
Rolling on too much throttle while exiting a corner can overwhelm the rear tire’s grip, especially on a powerful bike. The tire spins, the rear kicks sideways, and the natural reaction is to back off the gas. That’s the same trap: the tire grabs, the bike whips upright, and the rider gets thrown. The most common trigger for a high side in professional racing is actually oversteering to avoid a low side, which means the rider was already in trouble and made a correction that traded a slide for a launch.
Why Instinct Works Against You
The cruel physics of a high side is that the “safe” reaction, letting off the brake or throttle, is exactly what triggers the violent part. If you keep the rear tire locked or spinning, the bike will slide out from under you in a low side. That’s a much better outcome. Experienced track riders and racers know this: once the rear is sliding in a curve, commit to the slide. Fighting it by releasing inputs is what turns a manageable crash into a catastrophic one.
This is counterintuitive and extremely difficult to execute under pressure. Your hands and feet want to let go of everything when the bike starts misbehaving. Training yourself to hold the rear brake when the tire is already locked, or to manage throttle smoothly rather than chopping it, takes deliberate practice. Many track schools and advanced riding courses specifically drill this scenario.
How Modern Electronics Help
Traction control and stability systems on newer motorcycles are specifically designed to prevent the conditions that cause high sides. Bosch’s motorcycle stability control system, used across many brands, relies on a six-axis inertial measurement unit that reads the bike’s acceleration and lean angle 100 times per second. Wheel speed sensors independently track how fast each tire is rotating.
When the system detects the rear wheel spinning faster than the front during acceleration, cornering traction control steps in and reduces engine torque before the tire can break loose. Because the system knows the bike’s lean angle, it can intervene earlier and more precisely in corners, exactly when high side risk is highest. Additional features like wheelie control and rear-wheel lift-up mitigation address related scenarios where the bike’s attitude is changing dangerously.
These systems don’t make high sides impossible, but they’ve dramatically reduced their frequency. On bikes equipped with modern IMU-based traction control, the electronics can catch a rear tire spin and dial back power faster than any human could react. For street riders, this technology is one of the most meaningful safety advances of the past decade. It’s now standard on most mid-range and premium motorcycles, and it’s worth understanding what your bike offers and keeping those systems enabled, especially in corners.
Reducing Your Risk
Smooth inputs are the single best defense against a high side. Abrupt throttle changes and aggressive braking while leaned over are the two actions that start the chain reaction. Rolling on the throttle gradually as you exit a turn, rather than snapping it open, keeps the rear tire within its grip limits. Using primarily the front brake for hard stops and being gentle with the rear brake in corners eliminates the most common lock-up scenario.
Tire condition matters more than many riders realize. Worn tires, cold tires, or tires on a slippery surface all have less grip to spare before they break loose. Wet roads, painted lines, metal manhole covers, and oil patches all reduce the margin. If you’re riding on compromised traction, everything needs to be even smoother and more gradual.
If the worst happens and the rear does step out mid-corner, the counterintuitive rule applies: don’t release the rear brake, don’t chop the throttle. Let the bike low side. A slide you can walk away from is always preferable to a launch you can’t control.