Quote:
Originally Posted by jethead
Sorry, What's a tank slapper? I'm not familiar with this term......
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Its a situation where the righting force of the motorcycle's front trail geometry overcompensates for the degree to which the front end has stepped out of line with the back end. The result is a harmonic oscillation of the front steering axis.
It happens for a number of reasons, the most common of which is setting down a wheelie with the front wheel at an angle or position that is out of line with the rear.
If you are familiar with a steering damper, they are put on SS bikes with acute rake angles specifically to avoid a tank slapper.
Another term for this is "headshake"...if headshake gets so bad that the front fork is going lock-to-lock...its called a tankslapper (as the grips appear to be slapping the tank).
Here is a great video, showing a tank slapper in motion:
YouTube - Tank slapper Isle of Mann TT
p.s. - If this happens, the best thing you can do is to give the bars ZERO feedback. A proper motorcycle will have the geometry needed to work out headshake on its own. Any attempt to try and muscle the tankslapper away will result in a sure wreck. Actually, the best thing would be to let go of the bars entirely, but most people could not do that.