How to Not Get Tank-Slapped

Tip #90 from the Total Motorcycling Manual

The tankslapper is a force to be reckoned withCycle World

Also known as the the death wobble, the speed shimmy, or, for the more technically minded, the undamped second-order positive feedback mechanism, the tankslapper is a force to be reckoned with. It’s a rapid back-and-forth oscillation of the handlebar, often increasing in force and amplitude. The small ones can be either entertaining or terrifying; the large ones inevitably will leave you looking for a soft place to land.

The baby tankslapper cycles back and forth two or three times and then goes away. A big one grows faster and more intense until either you crash or it yanks the bar right out of your hands, and then you crash.

What causes it? A whole variety of contributing factors: tire stiffness, forward weight transfer, road surface, and chassis stiffness. Wheelie your bike long enough for the front wheel to quit turning, land hard, and you’ll often conjure one up. The most common causes are exiting a bumpy corner or a sudden weight transfer.

What should you do? First, don’t let go. Second, stop doing whatever it was that brought it on. Of course, this is easier said than done, but usually you should slide back on the seat and take some of the weight off the front end with the throttle.

And, of course, the best method is to fit a steering damper before the fact—which is why you’ll seldom see a race bike without one.