First tank slapper

[p.dath]

Experienced my first tank slapping incident yesterday. Just a small one.

Been experimenting with using a much lower gear while cornering, so as to keep the bike in its powerband.

Anyway, was coming out of a left hand corner yesterday, poured on the power, felt the steering go light, and then the bars started flicking left and right. I was holding on gently to the bars and they ripped out of my left hand. Things seemed to go in slow motion for a while.
Can't remember what my right arm was doing. It was still holding on. Think I kept the throttle on. That part is a blur.

I was on the exit of the corner with plenty of space, so pretty much left the bike to do its own thing. A short while later it self corrected, and I was able to continue on riding like normal.

Now that I've had a small taste of what its like it doesn't seem so fearfull. Hopefully if it happens again I'll be able to retain control.

There's probably something your meant to do while having a tank slapper (to retain control). But to be honest, my brain really wasn't capable of additional thought process while it was happening. I'd equate my experience to emergency braking. Once your in the middle of the procedure it has to happen automatically because your conscious brain doesn't have spare concentration.
Unlike emergency braking, not sure I'd bee keen to practice tank slapping too much. Not sure I could even make it happen again on purpose.

I'm guessing I applied to much power (duh!), and the front wheel started to lift a tiny amount (hence going light), or perhaps there was just too much power going to the rear wheel making its contatc much much larger that the front tyre.
I'm not sure.


Now I just need to experience a front wheel slide ...

[Motu]

Your front wheel lifted,or had very little contact with the road,countersteering then puts a much greater amount of lock on,the front wheel gets contact again and the steering centralises,over corrects....producing a tank slapper.

[YellowDog]

Hey Dath Vader, it sounds to me like you did an excellent job of managing a potential show-stopper.

Well done for keeping your cool :clap:

[one fast tl1ooo]

Sound's like you had a good save..

[{.bLanK}G_o_D]

I experienced a tank slapper once on my old NSR mc16. Not a particularly thrilling experience I might add.
I was exiting an open road corner fairly hard on the gas and hit a pretty small bump in the road, enough to lift the front tyre and start it slapping.

Steering damper FTW!

[BMWST?]

Experienced my first tank slapping incident yesterday. Just a small one.

Been experimenting with using a much lower gear while cornering, so as to keep the bike in its powerband.

Anyway, was coming out of a left hand corner yesterday, poured on the power, felt the steering go light, and then the bars started flicking left and right. I was holding on gently to the bars and they ripped out of my left hand. Things seemed to go in slow motion for a while.
Can't remember what my right arm was doing. It was still holding on. Think I kept the throttle on. That part is a blur.

I was on the exit of the corner with plenty of space, so pretty much left the bike to do its own thing. A short while later it self corrected, and I was able to continue on riding like normal.

Now that I've had a small taste of what its like it doesn't seem so fearfull. Hopefully if it happens again I'll be able to retain control.

There's probably something your meant to do while having a tank slapper (to retain control). But to be honest, my brain really wasn't capable of additional thought process while it was happening. I'd equate my experience to emergency braking. Once your in the middle of the procedure it has to happen automatically because your conscious brain doesn't have spare concentration.
Unlike emergency braking, not sure I'd bee keen to practice tank slapping too much. Not sure I could even make it happen again on purpose.

I'm guessing I applied to much power (duh!), and the front wheel started to lift a tiny amount (hence going light), or perhaps there was just too much power going to the rear wheel making its contatc much much larger that the front tyre.
I'm not sure.


Now I just need to experience a front wheel slide ...

practise hard stopping a few times....you should experience a front wheel lock up...dont SLAM on the brakes just increase the pressure .I used to try to do long front wheel skids on purpose,but i always let the front brake off when the front wheel started to tuck under.Front wheel slides whilst leaning are much less predictable and can be instant and result in a n instant lowside.Front wheel loock ups are preceded by a lot of "scrabbling" noises from the front tyre

[CookMySock]

Your front wheel lifted,or had very little contact with the road,countersteering then puts a much greater amount of lock on,the front wheel gets contact again and the steering centralises,over corrects....producing a tank slapper.So the rider could minimise this by taking his weight off the bars?


Front wheel loock ups are preceded by a lot of "scrabbling" noises from the front tyreWhile laid over? Or just when upright? I figured the result of a front lockup when laid over was immediately catastrophic, which is why I didn't think it was worth practicing it.

Considering 90% of my riding was in the dry, and that I had Michelin PR2's, the chances of me physically being able to lock the front were microscopic.

Steve

[puddy]

Yeah, I remember my first one! I was 19 and was single at the time. She had been with at least half of the team already, or so the stories went....
....she wasn't unattractive, but had a bit of an Amy Winehouse kind of air about her.
We were all out on the town, and, well, you know the rest!:rolleyes:

[puddy]

FUCK, sorry, never saw the word TANK!

[OutForADuck]

Tank slappers are a combination of rubber wheels, front end lightened and rough roads (or just a stone can do it if you have enough wegiht off).

They are caused almost in reverse of how you steer through counter steering, i..e you turn the bars, cause twisting force in the tyre which moves the front wheel outside the arc of travel and you turn.

With a tank slapper the road surface creates tyre twist, which is transmitted back to the handle bars as well as causing the wheel to move outside the arc of travel and steer you, which causes more twist, etc etc.

It all happens when the tyre is unweighted and will happen at the frequency of your steering geometry (i.e. fast turning bikes (steep steering angles) more prone) and tank slap faster.

If you pick the front wheel right up its affect is immediately removed and slapper stops (watch racers going over a ripple strips).

If you hold the bars you add torsional force (rather than damping it out) and usually increase the tank slap - so be careful of trying to "hold onto them too hard".

If you suddenly add weight, you better ensure your twisting force is neutral at the time or you are going to add power to the slapper - so try not to back off suddenly.

Ride it out and let it swing is best if you don't fancy just lifting it up a bit higher first.

BTW, letting it slap, it will usually sort itself out as it did with you p.dath.

Just remember if you want to start one, lighten the front on a rough surface or leant over (or land the wheelie slightly off centre :clap:)

Not to do with the back patch getting bigger.... to do with you getting alot more drive out of corners and ligthening that front wheel whilst you are leant over.... get a steering damper and keep riding it harder!!!

[OutForADuck]

FUCK, sorry, never saw the word TANK!

Not a lot of difference in either is there... screw the thing to the stops and hold on in both cases :rolleyes:

[p.dath]

Hey Dath Vader, it sounds to me like you did an excellent job of managing a potential show-stopper.

Well done for keeping your cool :clap:

I don't think I had enough spare concentration to be able to panic. :)


So the rider could minimise this by taking his weight off the bars?

After much mentoring and riding with others I've learnt not to put weight on the bars (aka, use my knees and core body strength to hold myself on the bike).


Yeah, I remember my first one! I was 19 and was single at the time. She had been with at least half of the team already, or so the stories went....
....she wasn't unattractive, but had a bit of an Amy Winehouse kind of air about her.
We were all out on the town, and, well, you know the rest!:rolleyes:

That is so hilarious. Maybe you read what you wanted to see. :)

[PrincessBandit]

Only ever experienced one (small one) on the bandit and have no desire to repeat. I can't quite remember what I did apart from throttling off very gently and making sure I didn't grip the bars too tight. I do remember my bpm being rather elevated for a while on the remainder of my trip!

[86GSXR]

I had one on my first Tiger. A very nasty and uncontrollable one despite trying very hard to stop it. Wrote off the bike and put me in hospital. Much pain :pinch:

[george formby]

Jolly good fun. I love making my bars waggle coming out of corners. The tank slapper you want to avoid is from a bent frame, knackered tyre or losing a balancing weight. Smacking both thumbs alternately off the tank at 120mph is terrifying.

[FJRider]

Yeah, I remember my first one! I was 19 and was single at the time. She had been with at least half of the team already, or so the stories went....
....she wasn't unattractive, but had a bit of an Amy Winehouse kind of air about her.
We were all out on the town, and, well, you know the rest!:rolleyes:

Those slappers are built like a tank ... :rolleyes:

[YellowDog]

Yeah, I remember my first one! I was 19 and was single at the time. She had been with at least half of the team already, or so the stories went....
....she wasn't unattractive, but had a bit of an Amy Winehouse kind of air about her.
We were all out on the town, and, well, you know the rest!:rolleyes:
The never look as good in the morning:

http://www.s1sb.com/images/amy_winehouse.jpg

[vifferman]

Meh.
Both the current bike and previous one (FahrtSturm) would waggle the bars coming out of corners hard on the gas in second. Love the feeling of sliding the rear then having the front coming up as the rear tyre hooks up. :clap:

Fortunately, neither had radical enough steering geometry that things got out of hand, although I've had the steering very slightly crossed up and then it's jerked itself straight again as the front tyre's gripped again.

[Ixion]

That's head shake , not a slapper. Still very frightening and dangerous though. A slapper is when you get head shake (like happened to you), BUT it happens that the shake frequency is a harmonic of the natural resonance frequency of the frame. So the oscillation becomes self amplifying, and the "slap" gets worse and worse, until it smashes the lock stops off and smashes the forks into the tanks (and mashes your hands if they're in the way). Fortunately, a true tank slapper is very very rare nowadays.

[p.dath]

That's head shake , not a slapper. Still very frightening and dangerous though. A slapper is when you get head shake (like happened to you), BUT it happens that the shake frequency is a harmonic of the natural resonance frequency of the frame. So the oscillation becomes self amplifying, and the "slap" gets worse and worse, until it smashes the lock stops off and smashes the forks into the tanks (and mashes your hands if they're in the way). Fortunately, a true tank slapper is very very rare nowadays.

Gees, hope I get to avoid that happening!

[FruitLooPs]

Gees, hope I get to avoid that happening!

Like so :crazy:
http://www.youtube.com/watch?v=V1W5HN40bpw

[McJim]

I experienced my first one at Pukekohe a couple of years back. Just turning into the back straight on a ZX636 and pinned it. Front wheel lifted, I eased the throttle to bring the wheel back down and it was not in line hence started wobbling a bit. Didn't ease the throttle but tucked down on the tank to lower centre of gravity and all was well so pinned the throttle again and enjoyed the rest of the back straight :2thumbsup:

Did another one recently in town exiting a roundabout a wee bit too briskly :rofl:

[cowboyz]

the 9 coupled with really shit suspension, headshakes are really common. I think Im just so over it now I just dont bother getting excited about it. Had 2 or 3 tank slappers. A beauty in the wet passing a car. That was a entertaining 45mins (or was it 1.5 seconds.. felt like longer) I dont care what anyone says.. if you get in a real tank slapper and get out of it.. its pure dumb luck you didnt get spat off.

[Kiwi Graham]

Good on ya for getting away with your first tank slapper Phil, sounds like you did all the right things.
Once youve had a tank slapper always give the front brakes a couple of pumps, bad ones can shake the pistons back into the calipers.
Not doing this could induce your next experiance, when you get to the next corner, grab a handful of front brake to realise it aint there! Tip in anyway and wham, there's your front wheel slide ha ha. Two experiances in one go!!

[p.dath]

Good on ya for getting away with your first tank slapper Phil, sounds like you did all the right things.
Once youve had a tank slapper always give the front brakes a couple of pumps, bad ones can shake the pistons back into the calipers.
Not doing this could induce your next experiance, when you get to the next corner, grab a handful of front brake to realise it aint there! Tip in anyway and wham, there's your front wheel slide ha ha. Two experiances in one go!!

Pump the brakes, ok will try and remember that one.

[lanci]

I hope I don't encounter the full on tankie, the recent head shakes aren't too bad as the wide bars on the Trumpy make it seem controllable.

[PeteJ]

Phil, please remind me at the next ART day to have a chat with you about this.

[Scotty595]

My first one was more a a head wobble than a full on tank slapper still scary all the same, my second one was pretty scary though, going along the motorway in the wet, felt pretty lucky to get out of it, although i think some of what has been said in other threads helped keep me up, although the foot coming down touching the motorway to stabilise the bike was pure luck that it worked.