What is meant by 'Tank Slapper'?

[grotbag]

I read this on another thread

my friend just had a nasty accident on her Z750 which was caused by a tank slapper.

But I have no idea what a tank slapper is?

[jonnywombat]

This would be a good example

Hope that helps

[grotbag]

ahhh a serious case of the wobbles, thanks jonny

[jonnywombat]

There is a lot of science going on to understand and prevent tank slappers, with the goal to design them out of bikes..

Put simply if you are going just the right speed and hit just the right series of bumps it will cause an oscillation in the bars. Instead of dying away, like a normal twitch, they increase in severity.. as the frequency of the oscillation matches the harmonic frequency of the bikes steering/suspension set up..(the same phenomenon that makes a tuning fork hum, or the Tacoma narrows bridge collapse) causing positive feedback, so every wobble feeds the next larger one.

If you experience this then apart from prayer you can take steps to try to reduce it..(although no guarantees here).. the way to try and regain control is a little counter intuitive... you have to release pressure on the bars, allowing them to move freely, and gently roll out the throttle a little bit..(but do not shut off completely)

Do not grip the bars tightly or apply the front brake!!!

Originally Posted by jonnywombat

you have to release pressure on the bars, allowing them to move freely, and gently roll out the throttle a bit..

Do not grip the bars tightly or brake!!!

I was taught (by an expert) to stop a tank slapper, do not throttle off, apply the back brake gently, this should stop the tank slapper.

[jonnywombat]

Originally Posted by papasmurf

I was taught (by an expert) to stop a tank slapper, do not throttle off, apply the back brake gently, this should stop the tank slapper.

Nothing is guaranteed to stop a full on tank slapper, sometimes you can recover sometimes not.. The info I have is from a meta analysis complied by the engineering dept of some uni somewhere... and will post link when I can find it again...

i have edited my above post for clarity...

Originally Posted by grotbag

I have no idea what a tank slapper is?

[MaccyMoo]

Originally Posted by papasmurf

That's exactly the image that sprung to mind!

[Shamblatron]

This is just the image that popped into my head, I have noticed something tho, GB is this another escaped smilie?

[Rerb]

They are like rats deserting a sinking ship

You be sure to keep your eyes peeled Shamb, your doing a sterling job