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Tankslappers - How to handle them.


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I spent half an hour typing this out for the sake of my track going kakis. I myself have experienced this tankslapping phenomenom before on my sportsbikes… to say the least, it is most unnerving when you feel 2 lumps in your throat. Hope this article will help you guys too.

 

Ride hard and ride safe on the tracks!!! - Raptor

 

The following article is an extract from the Roadracing World magazine.

This article was written by Misti Hurst, an instructress at the California Superbike School for Roadracing World magazine.

 

What’s a tankslapper?

 

A tankslapper is a rapid, high intensity and unwanted motion of the handlebars back and forth. Literally it is slapping of the bars from side to side that can get violent enough that it seems like they will actually hit the tank of the motorcycle, hence the name ‘tankslapper’. The bad news is they are scary as hell and can cause some pretty nasty crashes. The good news is that there are some very effective techniques you can use to handle them.

 

What causes tankslappers? The suspension on a motorcycle is designed to make the ride more comfortable for the rider and primarily to keep the tires in good contact with the road surface which can include bumps, cracks, potholes and all manner of other imperfections. This system must work while the motorcycle is straight up and down and also during turning when the motorcycle is leaned over, sometimes at very extreme lean angles.

 

In his book, A Twist of the Wrist II, Keith Code explains, “The process of head shake (which can be the beginnings of a tankslapper) begins when the tire hits a ripple and along with the suspension, compresses. This throws the wheel slightly off centre. When the suspension and tire release, the wheel is light and flicks back toward a centred position, but again slightly off centred. Still off centred when it loads again, from the next ripple, again it is flicked past its centred position. The cycle of flicking back and forth repeats as the front end seeks to stabilize through this automatic and necessary self-correcting process. Any bike will do it, and what most riders fail to realize is that this shake is a necessary part of the bike’s suspension system.

 

The little wiggle in the front of the bike is how the motorcycle self-corrects and gets itself back on track. Ever see a motorcycle race where something, either a tankslapper or a big slide, causes the rider to be ejected or fall off the bike? As soon as the rider is no longer on the bike, it wiggles a bit, straightens out, keeps on going perfectly straight until it runs out of momentum and falls over. This is a classic example of how a bike, when left to its own devices will sort itself out. Code mentions that “Based on the amount of wiggling, squirming and overuse of controls most riders exhibit, the bike would, if it could, surely ask them to leave. Riders create instability on their mounts.”

 

Headshake can be caused by hitting a bump or a ripple in the pavement or it can occur when accelerating hard out of a corner. Hard acceleration can cause the front to get light or wheelie, which means that the tire is not following the road very well and when it touches back down, it can skip or bounce or be off centre, starting the headshake. Code explains that “the good news is that if your bike is basically tight (steering head bearings not excessively worn, forks and shocks not sticking etc) the head shake always stays up front and does not transfer to the rest of the bike.”

 

Eventually, the oscillation will die out on its own, unless we interfere.

 

 

How riders make the situation worse.

 

A normal reaction when the handlebars start to slightly shake is to stiffen up on the bars. Keith Code calls this part of our “survival reactions,” noting that we do not usually choose to get stiff and tight on our bars, our bodies just do it. When we stiffen up the headshake is transferred though our bodies to the whole bike and that is when the shaking can get more violent. Code says that “too tight on the bars, is the most common source of motorcycle handling problems.”

 

How to prevent a tankslapper.

 

Knowing that gripping the bars to tight is what transfers head shake through the bike and makes it feel like a ferocious tiger ripping a piece of meat into shreds, we can work to prevent a tankslapper from ever occurring by maintaining a relaxed position on the bike at all times. Practice sitting on your bike with your knees gripping the tank for more stability. Sit back a little further in your seat so that your arms have a nice bend in them with your elbows pointed to the ground and then flap them like you’re doing the Funky Chicken. That’s relaxed, and from that position you can easily use your legs to lift your weight off the seat a little bit, like a jockey on a horse, so that your butt is not banging down hard on the seat. Think light as a feather, one with the bike. Zen and the art of motorcycle riding.

 

Installing a steering damper is another way to help prevent tankslappers. A steering damper works to limit the travel and intensity of any head shake the bike is experiencing by damping or soaking up the excess energy. They are necessary on some of the more modern bikes that have aggressive frame geometry, relatively short wheelbases and powerful engines. Dampers are mounted up front so that there is insufficient leverage to transfer shake through the bike. Keep in mind that a motorcycle with a damper will still shake if you are tight on the handlebars, so relax.

 

What to do if you experience a tankslapper.

 

If you do find yourself in the unfortunate situation of experiencing a tankslapper first hand, don’t try to muscle the bike or force it to stop as it will only make it worse. Try to relax your grip on the bars, pinch the tank with your knees and lift your butt off the seat a little bit. Also, don’t chop the throttle as that will put more weight onto the front and make the situation potentially more worse. Ideally you would want to continue to accelerate to get the weight further to the back of the bike, or at least maintain a steady and smooth throttle. Popping a wheelie would immediately eliminate a tankslapper because there would no front wheel bouncing back and forth in an effort to straighten itself out., but I don’t know of many people who could pull off a stunt like that in the middle of a panic situation.

 

If all else fails, let go. The bike will try to fix itself.

 

Another important thing to remember is that occasionally very violent tankslappers can knock the front brake pads and brake pistons away from the rotors, causing the brakes to go soft or fade completely. So once you regain control of the motorcycle, check the front brakes and if they feel soft then pump the lever a few times until the pressure returns.

 

Finding yourself in a situation where the motorcycle you are on is suddenly out of control is no doubt a scary predicament. The more knowledge you are able to arm yourself with, the better you are equipped to handle emergency situations and the more you are able to practice certain techniques (such as being nice and relaxed on the bike at all times) the more likely you will be to actually do it when it is absolutely necessary. It’s a pretty cool feeling to able to consciously decide to do something that makes a bad situation better.

http://i118.photobucket.com/albums/o104/angelo_neo/IMG_1208-1.jpg

 

FAA licenced motorcycle mechanic :angel:

 

Add me: http://www.facebook.com/raptormotorsports

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very informative. however, im riding a scooter, and unfortunately, there is no tank for my knees to grip onto. and to add to it, there is no bike shop in singapore that carries a damper for my bike. checked online. none either.

 

ive been experiencing this nerve wrecking 'tankslapping' quite a few times, but i still am not able to figure out as to how to counter-react to it. tried holding on to the handles harder, and like you mentioned, it didnt work. tried accelerating. didnt work either.

 

its true what you mentioned about the bike being able to sort itself out after a while. it does, but that 'a while' will get my [email protected]!!$ up my throat. and im too chicken **** to lift my butt off the seat in that situation.

 

so, if you do come across any other possibilities of eliminating this situation, please do share.

 

 

ps. tried closing my eyes and pray out loud. didnt work either. *sigh*

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have seen a video in this from forum teaching on how to encounter the tankslapper thingy but i cant seem to find it now though. iif i can remember the guy was riding a goldwing when he tried one.

 

while moving, he just knocked the handle bar causing it to wobble, however rider did nothing, no even the hands are on the handle bar, and after a few seconds it went back to a normal stable position.

 

one good video if one can track back.

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very informative. however, im riding a scooter, and unfortunately, there is no tank for my knees to grip onto. and to add to it, there is no bike shop in singapore that carries a damper for my bike. checked online. none either.

 

ive been experiencing this nerve wrecking 'tankslapping' quite a few times, but i still am not able to figure out as to how to counter-react to it. tried holding on to the handles harder, and like you mentioned, it didnt work. tried accelerating. didnt work either.

 

its true what you mentioned about the bike being able to sort itself out after a while. it does, but that 'a while' will get my [email protected]!!$ up my throat. and im too chicken **** to lift my butt off the seat in that situation.

 

so, if you do come across any other possibilities of eliminating this situation, please do share.

 

 

ps. tried closing my eyes and pray out loud. didnt work either. *sigh*

 

 

u doesnt need a tank to overcome this tankslapper. just do the same as the theory and it goes well. me too riding scoots and i did try as well. if you are scared, dun try though, ya bike may ended up sleeping on the road. however its a normal human reaction to hold tight to the handlebars when **** happens. hehe

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Superb article, Angelo!

I'll bear that in mind (plus steering damper) to minimise tankslapping if it ever happens again. :thumb:

Co-Moderator for IT -inerary forum

Biker nerd • Windows • Apple Mac • Android user

 

"Kick up your sidestand bro, let's ride..."

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Thanks for the effort, Raptor. Much appreciated... :thumb:

First learn stand, then learn fly. Nature's rules biker-sans. Not mine...

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The more we get together, the FASTER we'll be..

 

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  • 3 weeks later...
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Damn It, I Just Realised That I Encountered This Tank Slapper On My 2nd Day At Track,upon Exiting Turn 4,(really Cant Remember What Happened) And I Was Thrown Off My Bike,as I Lay Flat On The Tarmac I Was Amazed When I Looked Up And Saw My Bike Still Going Straight,unfortunately It Headed Straight To The Side Wall After Turn 4..and Then Came The $1000+++ In Repairs...but Thanks To Raptor,now I Know More About It..and Can Maybe Prevent It In Future.thanks For The Explanation Raptor.

'He who is afraid to take risks will accomplish nothing in life'

-muhammad ali

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  • 5 weeks later...
Guest deganduss
Damn It, I Just Realised That I Encountered This Tank Slapper On My 2nd Day At Track,upon Exiting Turn 4,(really Cant Remember What Happened) And I Was Thrown Off My Bike,as I Lay Flat On The Tarmac I Was Amazed When I Looked Up And Saw My Bike Still Going Straight,unfortunately It Headed Straight To The Side Wall After Turn 4..and Then Came The $1000+++ In Repairs...but Thanks To Raptor,now I Know More About It..and Can Maybe Prevent It In Future.thanks For The Explanation Raptor.

 

Theoretically you can try to prevent it but wen it really happen, good luck.

even world champion find it difficult to counter

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Damn It, I Just Realised That I Encountered This Tank Slapper On My 2nd Day At Track,upon Exiting Turn 4,(really Cant Remember What Happened) And I Was Thrown Off My Bike,as I Lay Flat On The Tarmac I Was Amazed When I Looked Up And Saw My Bike Still Going Straight,unfortunately It Headed Straight To The Side Wall After Turn 4..and Then Came The $1000+++ In Repairs...but Thanks To Raptor,now I Know More About It..and Can Maybe Prevent It In Future.thanks For The Explanation Raptor.

Mine whacked violently from left to right while exiting turn 8 that it veered off track.

That was my 3rd -- and the only one that sent me to the ground.

 

One track rider (he surf SBF by the way) asked what happened. He quipped "it's not the rider's fault?" when I began looking at my bike. :lol: :giddy:

Co-Moderator for IT -inerary forum

Biker nerd • Windows • Apple Mac • Android user

 

"Kick up your sidestand bro, let's ride..."

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Guest deganduss
Mine whacked violently from left to right while exiting turn 8 that it veered off track.

That was my 3rd -- and the only one that sent me to the ground.

 

One track rider (he surf SBF by the way) asked what happened. He quipped "it's not the rider's fault?" when I began looking at my bike. :lol: :giddy:

 

1 of the best way is pull a wheelie but only if your bike have enough power like motogp bike.

 

The whole thing can b avoided if you are smooth rider:thumb:

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1 of the best way is pull a wheelie but only if your bike have enough power like motogp bike.

 

The whole thing can b avoided if you are smooth rider:thumb:

 

1 of the best way is pull a wheelie but only if your bike have enough power like motogp bike.

 

Ya sure this can be done?

 

Even if the rider can (ever) reach his throttle to perform a wheelie even if his handlebars are whacking back and forth, will lifting the wheel off the ground actually help?

 

I held this off for a year, but I decided to come back today to provide a reply to your response because a member I went with for a short sightseeing trip months ago actually said the same thing and even quoted your post! :giddy:

 

EDIT: Got my answer already

 

Popping a wheelie would immediately eliminate a tankslapper because there would no front wheel bouncing back and forth in an effort to straighten itself out., but I don’t know of many people who could pull off a stunt like that in the middle of a panic situation.

Co-Moderator for IT -inerary forum

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"Kick up your sidestand bro, let's ride..."

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  • 6 months later...
wOow! tanks for the info... aniwaes tankslappers can happen at high speeds only????

 

I.M.H.O Not only at hi speed,,but depends on road condition,n bike suspension,,mostly happened while cornering..low or hi speed..Just my opinion..anyone..? :cheeky:

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I.M.H.O Not only at hi speed,,but depends on road condition,n bike suspension,,mostly happened while cornering..low or hi speed..Just my opinion..anyone..? :cheeky:

 

Hey there, I've got one:

 

I have had scratched-up forks in which most of the fork-oil fluid had leaked out, and tyres that were not made for rough track environment (tyres with a hard compound, made for road).

 

As a result, back in 2006, my bike wobbled whenever it hit camber changes mid-turn (Turn 5), and wobbled a few times at some other places I can't remember.

 

When I tried in the 5 lap race, the bike finally tankslapped when I powered out of Turn 8. That sent me off the track.

 

I had both rectified, and the insane wobbling went away.

Edited by redbeacon

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let me share my experience even i'm not track rider.

 

basically wrong set up for bike.. 3 box at rear.. semi-offroad tyres at front, speeding on NSHW.. and there ya go.. i had a few tankslappings..

it could be cross winds or waves on road..

and first a few time, i closed throttle (with help of rear break) and bike slowed down from 160+ to 80 yet handle bars swing left and right...

 

the next time, i tried to open more throttle (not till power wheelie) but it really helped on handle bar swinging.. and i can control the bike more stable..

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  • 5 months later...

very useful info for tankslap

Don't just break your laptimes, SHATTER them!!

 

Insanity is doing the same things over and over again and expecting different results - Albert Einstein, a German born theoretical physicist widely known as one of the greatest of all time

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LOL, got this during a race back in 1998 entering PG BMW 1st bend. And then again on the next last lap. Never experienced it that time even though have been riding since 1986.

Neverthless, very good info that I'm not aware of, Angelo.

20 years of riding:-

Bikes:

1986 - Yamaha RX100

1987 - Yamaha LC125

1988 - Yamaha LC350

1989 - Yamaha FZ400

1991 - Yamaha FZ750

1995 - Suzuki GSXR750

1997 - Kawasaki ZXR750K2 (race bike)

2002 - Yamaha FZR1000

2003 - Honda VFR800Fi

What's next?

Cars:

1996 - Nissan 100FA

1997 - Hyundai Elantra

1998 - Honda Civic

2001 - Toyota Corona

2002 - Renault Scenic

2004 - Toyota Picnic

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