Tank Slapping

Joined : 31 Mar 2008 Posts : 33

Hi guys....

What causes tank slapping?

Question

Joined : 17 Mar 2008 Posts : 128

I could tell you my version but need to make sure all members are over 18 Razz

Joined : 31 Mar 2008 Posts : 33

ohh.... c'mon... don't tell me it's due to loneliness.... You don't look that bad, schackster... haha... What a Face

well... seriously... please... c'mon... is the tires? the rider's weight? wind? design? handle bar? ...... Shocked

Subject: Re: Tank Slapping Thu May 01, 2008 9:50 am

Thank you John for bringing up this timely question, just recently, at the beginning of the month, one of the superbikers from another group had a unfortunately fatal encounter with a tank slapper.

A tank slapper explained simply is when the front steering uncontrollably sweeps the handlebars side to side at a very fast rate. (imagine u shaking your head like a 'feng tau' addict!) technically it has to do with what is called harmonic oscillation. As you ought know with motorcycle geometry and physics, a body in motion thends to stay in motion, due to the particular play of gyroscopic effects a wheel in motion will remain upright and move in a straight line as long as there is enough energy to do so, thats why the bike stays upright and if u dare u can take ur hands off without the bike falling over.....

But lets say the front wheel left the ground ( as in a wheelie) or due to uneven road surface or a bump or dip, if your wheel is not aligned when it recontacts the road, the bike will try to correct it to the straight upright position as per gyroscopic dynamics. sometimes it overcompensates this correctiona nd results in the harmonic oscillation, in other words the bike's front starts to shake, each wobble resonates so to speak and amplifies the effect so it rapidly builds up to a violent uncontrollable shaking or oscillation of the front steering.... the bars swing left & right sometimes hard enough to hit the tank or nearly ( at maximum turning angle lock) Hence the term ' tank slapper'

Unless you can effect corrective measures to bring the front stering under control, the almost inevitable result is a crash!

there are as many factors, theories and schools of thought on what exactly causes tank slappers and the way to get yourself out of one once it has occured. the list is quite extensive, but u can google up more info than i can list here, there is a video of the Isle of Man TT where a rider has a tank slapper at speed, I saw it and it looks S**T scary!!! the only thing worse than watching it is having it happen to you!.....

Which brings me to the next point. Yes, i do know what its like personally. I had a fairly low speed Tankslapper in the raain going uphill after a left turn, the bike did the actions stated above, the front slapped and the rear did its own hula dance in reverse and totally out of synch, not not at all like a high speed wobble but a freakin bronco busting death roll, the bike then flipped up in the air sideways like a reverse lowside ( lowsided into the air) at which point i got thrown to the ground....... and the the bike fell on top of me!

Lucky it was just an EX5 and lightish, the road was streaming with lubricating water to dampen the blow,and that i had my goretex rain suit on( no internal armour padding tho). A few sratches and cuts, bruised hip and other minor injuries.. I picked up the bike and rode it back home, dressed the wounds and rode out again (i was riding out to pick up a new bike i bought)

What I learned:

Always wear protective gear
Dont ride in a pissed off mood after an argument
Have respect for the road conditions
Watch out for rain and its effects on the road
Ride Defensively
Stay focussed but calm
Pray

If you get a tank slapper, do everything you posibly can to regain control, Pray.. ( screaming Oh F**K!!!!! into your helmet is not a valid prayer!). If you cant control it and its goingg down, skillfully dismount your bike (like some kung fu stuntman using wires, and land in a cool authorative pose on the road, like 'matrix' or the chick in 'underworld' when she jumps from the rooftop). a quick sweeping glance of the road to make sure u are not 0.2 seconds from being plastered by a bus, then roll or hop skip & jump to the pavement as the bus u just missed grinds ur bike under its multi tonnage or wheels!

turn away and cry into ur helmet (R.I.P. your bike), while smiling and thanking every god u know its was not u under the wheels.

Check for bodily damage, and signs of shock, apart from the fact that u narrowly missed certain doom.

Oh, and dont forget to post the experience in detail on the Spitfire website so that Schackster can have something new to read about, because the forum is so boring......

Btw, all the above is just my 2 sen worth, and some would say its not even worth that much, who cares... my right to share..., anyway, now some links:
http://www.slash5.net/org/Tank%20Slapper.html

http://www.ducati.ms/forums/showthread.php?t=35548

http://www.600rr.net/vb/showthread.php?p=226428

http://www.msgroup.org/forums/MTT/topic.asp?TOPIC_ID=409

For some general info on bike physics n theory:
www.msgroup.org/forums/MTT/forum.asp?FORUM_ID=198

Subject: Re: Tank Slapping Thu May 01, 2008 10:46 am

Subject: Re: Tank Slapping Sun May 11, 2008 5:48 pm

LOL, yeah i thought that might have been a contributing factor to my tankslapper. anyway.. the new GF turned out to be a 'China Bi*ch' low class , high maintainence pain in the ass.. and she dumped me many times.... last time was as a result of the Tsunami in penang... (Why does almost dry sea mud look like grey asphalt when its dry i wonder?)

Anyway, i am beyond hope.. now planning to spend $XXX to send her for plastic surgery so she looks like a high class china bi*ch, and she will prob still give me the same attitude!....

lucky i got more options for rides, plus two orphans.... but dont tell that highly strung godess that she is one or she may slap me too Sad

.. Wonder when her mama going to come back n sayang her?

Subject: Re: Tank Slapping Mon May 12, 2008 2:07 pm

Dang!!! Your analogies are hilarious, khai!!!

And oh, aside from one-too-many-high-speed wheelies, I believe that suspension set-up & maintenance of cone bearings has some part to play in it as well.

Subject: Re: Tank Slapping Mon May 12, 2008 3:03 pm