Tankslappers explained

[idleidolidyll]

damn the demon drink! hic!

came here looking for 'tanked slappers' only to find a bunch of motorcyclists talking bike stuff

my 'polagies

[idleidolidyll]

Only my opinion!

I hate the linked break thing, I really believe that the rider should be in controll of there own destiny, but I also hate ABS systems, you cannot stop as quick with ABS as you can with a normall system

agreed

anecdote:
owned a motorcycle courier business in Cardiff, Wales. One day my bus partner and I headed off to Caerphilly over the mountain for a spin and I watched Scelly pull into the big layby at the top where the obligatory burger cart lurked surrounded by customers and people looking at the view. Scelly was in front by a good margin and as he hit the gravel he hit the rear brake and slid into a nice controlled stop with the crowd in awe.

Thinking "shit, that was cool" I started to do the same thing only to remember too late that I was on a Guzzi with linked brakes.

I'm still not sure what was more painful: the gravel rash or the hysterical laughter from about 30 onlookers.

I hate ABS, it lacks feel and ultimate power and linked brakes don't do it for me as I use rear wheel braking a little to steer the KTM

[Morcs]

Ive had the vfr 2 days and ive already experienced 5 small tankslappers (3-4 turns of the wheel from side to side)

Its pretty much self induced though, when flat tack in first, changing to second aggresively it always seems to do it - is it more to do with the bike or me being agressive on the bars - clutch in hard, throttle off hard, clutch out hard and throttle on hard?

Its only scary when it actually happens on a bumpy piece of road, where the front wheel comes off the ground...

[Shaun]

Ive had the vfr 2 days and ive already experienced 5 small tankslappers (3-4 turns of the wheel from side to side)

Its pretty much self induced though, when flat tack in first, changing to second aggresively it always seems to do it - is it more to do with the bike or me being agressive on the bars - clutch in hard, throttle off hard, clutch out hard and throttle on hard?

Its only scary when it actually happens on a bumpy piece of road, where the front wheel comes off the ground...

By the sound of things, you are being to aggresive with handle bar controls input, try smoothing out your actions a little and see what happens

[TonyB]

Morcs- it could also be the forks. If the damping is shot, you'll get this problem a lot. On my FZR, this problem was frequent, when I was riding like a delinquent. So I had the forks repaired, and the problem disappeared.

[Toaster]

Had a wicked tank slapper last year on my previous bike -a GSXR. Lost traction on the rear just as I opened the throttle with wonton abandon, slapped that front around like heck and just managed to stay on.... slammed my foot down in the process and shattered one bone and split the other from top to bottom in my foot.

[terbang]

Must admit I prefer the 'tanked slappers' any day over the motorcycle kind. They're prettier.

[NordieBoy]

Its pretty much self induced though, when flat tack in first, changing to second aggresively it always seems to do it - is it more to do with the bike or me being agressive on the bars - clutch in hard, throttle off hard, clutch out hard and throttle on hard?

Less arm, more wrist.

[dank]

Both kinds of slapper are dangerous and expensive on the wallet.
Ive had many, the bike tends to do it sometimes also. wha whaaaah.

[Skyryder]

Na a tankslapper is a biker whose rodgered his ol' lady on the tank of his bike. It's why Harleys have two filler caps on each side. Give's the ol' girl somit to hang on to.

Skyryder

[ducatilover]

argh if only i read this in 2005......i was told to lean back during a tankslapper as to take the weight off the front wheel to reduce the harmonic imballance

[ducatilover]

this is waht my first real tankslapper did.... it kinda hurt too

theres a huge wrist dent in the tank lol. and im sure a few things may have fallen off.




argh pictures wont load

[idleidolidyll]

Well it's all about a lack of control of course.

The speed bump on the road of life that sets a slapper up for ridicule and derision is usually alcohol and yes, they get well and truly tanked sometimes.

However, at some time in their life, most men will seek a tanked slapper for a bit of recreation.

It's a natural thing.

[classic zed]

The best way I have found to get out of a tank slapper (and Iv had a few over the years) is to lay down on the tank, it lowers the centre of gravity and stops it almost immediately

[Roki_nz]

Not sure if you guys have seen it but go it from this site:

http://www.msgroup.org/tip.aspx?num=190


A tank-slapper (wild and rapid swings of the handlebars from hard-stop right to hard-stop left and back again) happens when harmonic feedback is generated following your front tire hitting an imperfection on the road surface such as the slight bump at the end of your driveway.

It usually happens at speeds of around 20 MPH - sometimes a little faster, sometimes a little slower - but it CAN happen at any speed!

I have heard otherwise well informed riders give advice to newbies about how to handle a tank-slapper. Usually it goes something like this: 'Just hit the throttle and lift the front-end off the ground. That will stop the oscillation."

Please! That advise is virtually assured of getting you into serious trouble - more than you were in when the tank-slapper began.

Harmonic feedback means that a small force is being applied EXACTLY in-phase with the end of a counter-force (shock absorber) which results in another 'bounce' of the system AND AN AMPLIFICATION of the previous bounce.

The second time it happens the amplification is huge. The third time and you eat asphalt - maybe the fourth time...

It is exactly the same principal that keeps your old grandfather's clock pendulum swinging - it gets a tiny 'kick' at exactly the right time (in-phase) at the end of each swing.)

Your bike probably has one of two kinds of devices in it designed to prevent these from happening:


A small shock absorber attached to the steering stem

A pressure bearing within the triple-tree
These are called steering head dampers or 'stabilizers'. Their sole legitimate purpose is to disrupt harmonic feedback and, thus, stop tank-slappers before they start. Some vendors (and motorcycle shops) will tell you to get one in order to stop your front-end from 'shaking'. NUTS! If your front-end shakes at any speed there is something wrong with the suspension.

If your steering head damper is weak or maladjusted then it cannot dampen (and, thus, kill harmonic feedback) shocks to the front-end.

As to suggestions about how to handle one if it happens ... it is NEVER appropriate or safe to do a wheelie. Your response should be to hold firmly to both grips and absorb the 'harmonic feedback' into your arms - i.e., dampen them - and grabbing a handful of the front brake. Then go get it fixed!

Your NUMBER ONE RESPONSIBILITY on a bike is to maintain control of it.

For those giving advice ... if your bike is already out of control do you really think it makes sense to increase speed? To do a wheelie? Does it not occur to you that you were traveling at some rate of speed and it was just a minor imperfection in the road surface that started this and that when you come back down from a wheelie, going faster than you were, that front-end is going to get a severe jolt? What do you think the odds are of going into another tank-slapper then?

You must disrupt the harmonic. You do that by stiffening your arms and changing the front-end geometry, if you can. Braking, by the way, both slows you down so that if you do hit the ground it won't hurt as much, and it compresses the front shocks which changes the front-end geometry.

Sound like a better alternative to you than hitting the after-burner?