Tank Slapper

A tank slapper is a rapid, violent side-to-side shaking of a motorcycle's front wheel and handlebars that occurs when the front and rear wheels become misaligned, causing the handlebars to swing so forcefully they may strike the fuel tank on either side.

This dangerous phenomenon is most commonly associated with motorcycles, though the term can also describe a similar oscillating loss of control in cars. When it happens on a bike, riders often describe it as one of the most frightening experiences in motorcycling because the handlebars shake so violently that maintaining control becomes extremely difficult.

The name "tank slapper" comes from the literal action of the handlebars slapping against the sides of the motorcycle's fuel tank during the violent oscillation. You might also hear this called a speed wobble, death wobble, or shimmy. All these terms describe the same scary situation where the front end of the motorcycle rapidly wobbles back and forth.

A tank slapper typically starts when something causes the front tire to become misaligned with the rear tire. The motorcycle's natural tendency is to try to correct itself and straighten out, but this correction creates momentum that swings the front wheel too far in the opposite direction. This overcorrection then repeats rapidly, creating the characteristic violent shaking.

Several factors can trigger this condition. Landing a wheelie too hard or at an angle is a common cause, as is hitting road imperfections like potholes or bumps at speed. Harsh acceleration that lifts weight off the front wheel can also start a wobble. Poor suspension setup, incorrect tire pressure, worn tires, or even strong crosswinds can make a motorcycle susceptible to tank slappers.

The dangers of a tank slapper are serious. The violent shaking makes steering nearly impossible, and riders can easily be thrown from their motorcycle. Crashes resulting from tank slappers can cause severe injuries including broken bones, head trauma, and muscle damage. Even riders who successfully recover from a tank slapper may experience lasting anxiety about riding.

Prevention is the best approach. Many riders install a steering damper, which is a device that dampens the side-to-side motion of the handlebars and helps prevent wobbles from developing. Regular maintenance of your suspension, tires, and steering components is also crucial. Keeping proper tire pressure and avoiding sudden throttle inputs can reduce your risk.

If you find yourself in a tank slapper, the most important thing is to stay calm. Resist the natural urge to grip the handlebars tightly or chop the throttle completely. Instead, relax your grip on the bars while gripping the tank firmly with your knees. Maintain steady throttle or even gently accelerate to transfer weight to the rear wheel. Leaning forward can also help by adding weight to the front end. These actions give the motorcycle the best chance to stabilize itself and allow you to ride through the wobble safely.