I've heard people say it and I've read it.
Something to do with a/x or track driving, I think.

A hard or abrupt turn without control that causes the fuel to slap inside the tank?

You to slap inside the car ( tank )

What is it?

Funny answers, if you don't really know, are strongly encouraged.

I'll sort it all out.

KT

I don't know.

LMAO!

a term borrowed from motorcycle riding (or crashing), where because of some instability the handlebars oscillate back and forth very quickly and out of control -- thus 'slapping' the tank back and forth.

loosely applied to driving, but a similiar effect can occur e.g. when a slalom maneuver gets a little out of control...

crotch rocket term

I think it's when you're driving on a Military Reservation and all of a sudden your windshield becomes full of TANK.....and then....you slap against the side of the TANK....Yeah, that's it.....yeah....

Nate's got it.

In a car, it would be when the back end gets very loose, you slide one way, overcorrect, it slides the other way, you overcorrect again, rinse, lather, repeat. Sometimes you get away with it, sometimes it just gets worse until you spin completely.

On a bike, it can happen even while you're just travelling in a straight line. Something like a bump or a gust of wind or going over a crest destabilizes the bike, and the whole bike "vibrates" at some natural frequency that's based on the various masses and how they're distributed. The bars waggle back and forth, sometimes hitting the stops (or the tank, if there are no stops) and sometimes crushing a thumb. This doesn't always result in a crash, but it always results in a seriously increased heartrate.

The instability is usually caused by lofting the front wheel a bit and landing it crossed up. It tends to happen most frequently when cresting a hill (or small bump) hard on the throttle, turning. (If caused by wind or load distribution it is called "swerve" and is cured by redistributing the load or removing the aftermarket fairing, but the bars do not wag, the bike does.) Supersport bikes are more likely to wheelie than others because of their short wheelbase and power, and more prone to slap because of aggressive geometry at the front. If your bike is prone to it you fit a steering damper which is essentially a gas/oil piston bolted between the frame and the handlebar to slow down its movement.

Minor ones are fun. Violent ones are scary as shit.

Next lesson: the highside.

Ask an old Brit bike rider ................ Sometimes you can find one who has calmed down after 20-30 years or so after it happened to him ............................ The Cap'n

Tank Slapper

Or, ask anyone who has ridden an RD400.

Click on the 1st video to see what a tank slapper looks like from the riders view.
http://www.gofastvideo.com/gallery/item/pr...willow,-ca.html
Then be sure to check out some of the other great race videos on this web site.

As a previous motorcycle racer, The term "TANK SLAPPER" can have many forms. The first is as described previously, the bars oscillate back and forth basically slapping the tank right and left. Back in the day, some bikes did not have steering stops so the bars were actually able to hit the tank. You get it several different ways. 1 st and most common is the landing from a sustained high speed wheelie, where the front wheel has been up long enough to slow, or the bike has accelerated while the wheel has remained the same speed it left the ground. This causes a speed differential and the wheel actually slips while trying to accelerate to the speed of the bike. This allows the front wheel to step slightly sideways and out of line with the rear wheel, the castering of the front wheel starts the wobbling shopping cart wheel effect and then the slapping of the bars right to left begins. It can be anything from a very sudden and high speed shake to a very slow back and forth motion of the bars that comes on very slowly. The second type will normally start on decel and is a frequency issue as opposed to a slip grip issue. My worst was on a test ride on a new unit while working for a dealership. Accelerating over a depressed manhole cover started a violent tank slapper with the bars actually being torn from my hands. it was going straight so I just put my hands out open palm and after the bars hit my hands 5-6 times the oscillation stopped. Some riders panic and make stupid decisions, like to bail off, but don't forget "objects tend to remain in a particular state util acted on by another force" If the bike is straight up and down, relax, don't make any sudden moves and wait it out it will stop. As the unit slows the natural frequency will change and the slapping will stop. Just keep it upright and pointed in the right direction. If I were to describe a TANK SLAPPER for driving my racecar I would say I I lost the rear, over corrected, and chased it back and forth over correcting each time. Some cars have such poor bump steer that the wheel will actually oscillate back and forth in your hand. This is an effect of caster and bump steer. It can be set off by poor shock damping characteristics (so can a motorcycle) poor tire choice (they also have a natural frequency) and binding of the suspension. Hope this helps. It is a coloquelism (sp).

Erik Madsen

QUOTE (Howard @ Jun 14 2005, 05:56 PM)

Tank Slapper

A very large pucker factor at work....

QUOTE (Midtowner @ Jun 14 2005, 05:56 PM)

Or, ask anyone who has ridden an RD400.

Me and yes it applies well. Been there done that and never want to do it again.

QUOTE (Howard @ Jun 14 2005, 05:56 PM)

Tank Slapper

[QUOTE]

clicking on the link made my computer freeze up!
WTF?

It's a term which describes an individual with a beer gut masterbating.

LOL. I can't find an appopriate smiley so I'l go with which is appropriate since I'm in New Zealand right now.


BTW: I just about fell of my chair when I clicked on and saw that it is : miles :

Watch the guy in the first vid. His inner thighs are slapping the tank......other more precious parts of your anatomy can become involved also....since your feet come off the pegs That's actually more of a power wobble.

A good slapper gets going with the back end bouncing up off the ground and landing off center....like over whoops.
The side to side bounce gets progressively worse (the death dance) till the bike spits you off.



The bitter end usually comes in the from of a "high side". You can really get some distance & elevation if you do it just right The more d & e you get (since you try to maintain your death grip on the bars), the more time you have to get your hands out in front of you....otherwise you do a "face plant".

A buddy that had a 400 RM was black & blue starting at one knee 180 degs thru the crotch to the other knee.

Thas all I learnt in 3-4 years of dirt bikin'. Stopped before I kilt meself.

Thanks.

Did that on Saturday...

KT

So many times on, so many bike, so many variables.
On all the bike I raced over the yrs I had a little meassage to myself near eye level
it said "RELAX"
The death grip is called that for a reason...
And yes High sides are VERY painfull

Did one of those last June; 210 FWY EAST near Pasadena/Sierra Madre. Going about 75 - 80 mph. .. The one time I was not wearing gloves!

Do Not Look!

QUOTE (Jacques @ Jun 15 2005, 04:35 AM)

Did one of those last June; 210 FWY EAST near Pasadena/Sierra Madre.  Going about 75 - 80 mph.  .. The one time I was not wearing gloves!

QUOTE (trekkor @ Jun 14 2005, 08:53 PM)

Thanks. Did that on Saturday... KT

Kinda figured that is why you were asking.....
Best thing to do is not fight it. The car will straighten out on it's own. Fighting it will only make it worse.
Smart ass driver a few moths ago got his Miata doing this manuever and just let go of the wheel. Car straighten up and he shot through the last cone and into the timing light gate a little sideways not hitting a thing.

QUOTE (Dave Eddy @ Jun 14 2005, 07:55 PM)

QUOTE (Howard @ Jun 14 2005, 05:56 PM) Tank Slapper [QUOTE] clicking on the link made my computer freeze up! WTF?

hmm, dunno. do a right click and 'save as'. see if that helps.

QUOTE (trekkor @ Jun 14 2005, 08:20 PM)

What is it? KT

guy who likes FAT (BBW) women?

lmao wayne...

Had a friend experience his 1st (and only) tank slapper a few years back. At about 80mph, his death grip cause it to get worse when it finally threw him off. The bike's right handlebar hit the ground which pinned the throttle, and it stood right back up and kept going till a parked truck on the side of the road stopped it. so yeah, the best thing to do is relax and ride it out, a little more gas takes the weight off the front and can help it straighten out, if you're going straight that is.

QUOTE (Jacques @ Jun 15 2005, 12:35 AM)

Did one of those last June; 210 FWY EAST near Pasadena/Sierra Madre. Going about 75 - 80 mph. .. The one time I was not wearing gloves! Do Not Look!

Let me guess, you were headed up to Angeles Crest? Good thing it happened on the 210 and not in the mountains!

BTW: Where in pasadena are you?

East 210 @ Sierra Madre would be going away from "the Crest".

Eric

QUOTE (MattR @ Jun 15 2005, 02:03 PM)

QUOTE (Jacques @ Jun 15 2005, 12:35 AM) Did one of those last June; 210 FWY EAST near Pasadena/Sierra Madre.  Going about 75 - 80 mph.  .. The one time I was not wearing gloves! Do Not Look! Let me guess, you were headed up to Angeles Crest? Good thing it happened on the 210 and not in the mountains!

I do frequent the Crest, but not on motorbikes. Usually to "Redbox" up Mt. Wilson Road. Albeit, very late at night; I've gone there as many as six times a week!

QUOTE

BTW: Where in pasadena are you?

Beautiful South Pasadena; near the Vons / Pavillions >> I usually have to park my overflowing 914 collection at the stores' side parking lot

No way, thats your red 914? Ive seen that parked there for a while and always wondered whose it was.

They just repaved the lot, where did it go?

I live on marengo... like across the street. If you go down lyndon until you hit marengo, stop by and say hi friday afternoon and check out my 914. It should be coming off the trailer at around 2pm

BTW: redbox is my favorite place to go. If you're in a rally car go to upper tujunga road. Theres a right hand turn after red box and it goes to some old building. Its great fun in the snow in a wrx

QUOTE

They just repaved the lot, where did it go?

eh, Amazing! Yeah I was out of town when the notices were placed, so they towed my '75. think I got it out the next day. Also my grey '70 is parked there sometimes. >> My 'race' 914s are in the garage (a '72 & '73) down Monterey.

QUOTE

and check out my 914. It should be coming off the trailer at around 2pm

yeh, sounds good