On The Edge Of A tankslapper - Stromtrooper Forum : Suzuki V-Strom Motorcycle Forums
General V-Strom Discussion Talk about all things V-Strom not limited to just one of the above models

Reply
 
LinkBack Thread Tools Display Modes
post #1 of 28 Old 04-13-2008, 02:58 AM Thread Starter
jwt
$tromtrooper
 
jwt's Avatar
 
Join Date: Feb 2008
Location: mexico?
Posts: 2,974
Question On The Edge Of A tankslapper

I've heard the "tankslapper" described on this forum, and some folks advocate a steering stabilizer to prevent this crash causing issue. I have a question to any of you that may have experienced a "tank slapper"--what did the edge of it before it happened feel like? I have a murphs forkbrace on the way because of my stroms skittish front end @ speed, and think I've came damn near a "tank slapper" trying to pin the throttle on windy days. What did it feel like right before the tank slapper happened for you?

"I believe the most damning thing that can be said about muslims is saying you're afraid to say anything."--Penn Jillette

Pointless Profanity Club member #10 ****face.

Best Auto/Moto Insurance | Motorcycle Protection Today | FREE Trade-In Quote
jwt is offline  
Sponsored Links
Advertisement
 
post #2 of 28 Old 04-13-2008, 08:01 AM
Stromthusiast!
Super Trooper!
 
Corkus's Avatar
 
Join Date: Oct 2007
Location: USA
Posts: 615
JW, I've never had a tank slapper but I think a half second before a Tank Slapper, the steering probably feels normal. They come on suddenly and there's usually nothing that can be done. They either throw you down or they don't and it seems to depend on how bad the situation is, not on how good the rider is.

I've heard lots of riders describe slappers on street bikes. One said he tried to save it by using his hands as a steering damper, releasing the bars and regripping them lightly. He didn't think it made a difference.

Powerful bikes accellerating over bumpy surfaces is a common cause. Sometimes high speeds can be sensitive to instabilities, bumps probably starting a reaction. Hitting big bumps like when riding in the dirt can cause a slapper. One big deal is keeping your balance because you don't want to fall off if the bike is going to right itself, but if the bike goes into an uncontrollable wobble, well, that's a nightmare and there's not much a rider can do.

Bottom line, you can put a steering damper on a bike and prevent slappers but trying to manage one is probably nearly 100% futile. Stroms aren't one of the more slapper prone bikes but since bumps can cause slappers they can happen to any bike I guess.

Cory
07 DL650A
Pleasanton CA
Corkus is offline  
post #3 of 28 Old 04-13-2008, 08:44 AM
 
Join Date: Mar 2008
Posts: 428
Here is a relatively "famous" video of a tankslapper

http://youtube.com/watch?v=LZ1srcQMa_0

The bike develops an oscillation due to an event that upsets the suspension and straight line stability. It can be a bump, it can be extreme accelaration, it can be high speed with poor areodynamics on a heavily laden bike, it can be a sudden loss of traction of one end of the bike, it can be setting down hard from a wheelie, (taking your hands off the wheel while decelarating?), usually it is a combination of things. The only pivot spot for the bike to oscillate around is the front steering. In the video above you are watching a professional, someone who makes a living riding at 9/10ths+. He is helpless to get the bike back under control, he is not the one moving the front wheel side to side. Watch closesly and the point of the triple tree is moving in a straight line, it's the rest of the bike that is all over the road.

It is possible to ride out a tankslapper, the bike really wants to go straight, the oscillation will eventually end. You will probably however go down, not because of your riding skill but because physics and traction are at odds in the middle of the event. The bike is moving around the pivot point, the front tire is doing the opposite of the rear trying to work itself straight, traction of the tires now work against you and can actually make the oscillation worse.

The steering stabilizer basically eliminates the pivot point at speed, if an oscillation starts it dampens it.. like a shock absorber attached to both sides of your handlebars.

What you experienced was probably not a tankslapper unless you were scared shitless, crying, seriously considering never riding again and perhaps lost control of your bowels. You probably lightened up the front end considerably by pinning the throttle and the wind moved the bike from one side to the other. The strom is relatively light and tall and the wind affects it more than smaller heavier bikes.

I encourage you to slowly explore your limits and your bike limits, invest in quality riding gear, take a msf course, do not take the bike to the strip bar and chill out on the bike, enjoy it and ride it, learn!
Bitter Born is offline  
 
post #4 of 28 Old 04-13-2008, 08:59 AM
Stromthusiast!
 
Join Date: Apr 2007
Location: Northern VA
Posts: 340
This youtube was listed after the one BB listed I think it shows the begining tank slapper in a straight line - from the cockpit - so it's pretty telling.

http://www.youtube.com/watch?v=5xLHOWojaOo&NR=1

Chuck

05 DL-1000 - A farkling project in the making....

"A free people ought not only to be armed and disciplined, but they should have sufficient arms and ammunition to maintain a status of independence from any who might attempt to abuse them, which would include their own government. George Washington
cbjr0256 is offline  
post #5 of 28 Old 04-13-2008, 09:09 AM
Stromthusiast!
Super Trooper!
 
Corkus's Avatar
 
Join Date: Oct 2007
Location: USA
Posts: 615
Quote:
Originally Posted by cbjr0256 View Post
This youtube was listed after the one BB listed I think it shows the begining tank slapper in a straight line - from the cockpit - so it's pretty telling.

http://www.youtube.com/watch?v=5xLHOWojaOo&NR=1
That is not a tankslapper, it is "headshake". That's perfectly normal on those bikes. That is what a steering damper does to a possible tankslapper on a literbike. I may have had that same model bike and a steering damper, never went to a track and rode like that though. I've felt the headshake. All you had to do was accelerate hard over bumps and there you go.

Multiply that by 200 times and you have a tankslapper .

Cory
07 DL650A
Pleasanton CA

Last edited by Corkus; 04-13-2008 at 09:17 AM.
Corkus is offline  
post #6 of 28 Old 04-13-2008, 10:03 AM
 
Nanuk's Avatar
 
Join Date: Jun 2007
Location: Grand Forks, ND
Posts: 26
I had a pretty good tank slapper on my 1400 Intruder several years ago. I was traveling down a gravel road on my way home from work, while I was at work they added 3" of golf ball sized gravel to the road, I hit that patch at 45 MPH. I was able to make it out without going down. Maybe not technically a tank slapper, but the front tire was not going where the handle bars were pointed.....
Nanuk is offline  
post #7 of 28 Old 04-13-2008, 11:52 AM
$tromtrooper
 
silverstrom's Avatar
 
Join Date: Jun 2007
Location: Near Tweed Ontario
Posts: 1,458
I did a classic tankslapper on a Yamaha RZ350 back in 1987. When all was said and done and I picked up the pieces the gas tank was as wide as the gas cap. The cap was all that prevented both sides of the tank from touching each other. It snapped both steering stops off and highsided me at about 75MPH. Trust me, if you have real tank slapper, you'll be the first to know and you'll never forget it. Ahhh..how I long for the days of my misspent youth. By the way, I just bought another RZ...stay tuned...

SS

DL650K7
1985 RZ500
1986 NS400R HRC
1987 RG250
1987 TZR 250
1988 RGV 250
1989 RZ 350 F2
1990 RZ 350 N2
silverstrom is offline  
post #8 of 28 Old 04-13-2008, 12:24 PM
Stromthusiast!
 
cbrxxcess's Avatar
 
Join Date: Feb 2008
Location: Medical Lake, Washington
Posts: 1,647
Send a message via Yahoo to cbrxxcess
From the tell tale sign to the event are going to be too short for you to do anything about it. If your pushing the limits of the bike, the road, or yourself these are all a good indicator that you may be on your way to one of those. I am sure that at much over 100 MPH and your pushing it. The way the fairing is set up on these bikes it makes the front light with the wind resistance. At that point all it will take is a small dip or bump and you can be off to the races. That is why you hear it talked about most when these bikes are heavy with gear on the back.

Keep the Rubber Side Down.
Jim
Present Rides
1986 XR600R,1986 VF1000R,1999 CBR1100XX,2006 CRF450X,2007 DL1000 V-Strom
[IMG]http://i412.photobucket.com/albums/pp210/cbrxxcess/Motorcycles/North%20American%20V-Strom%20Rally%202009/Canadamap.jpg[/IMG][IMG]http://i412.photobucket.com/albums/pp210/cbrxxcess/North%20American%20V-Strom%20Rally%202010/VisitedStatesMap.jpg[/IMG]
cbrxxcess is offline  
post #9 of 28 Old 04-13-2008, 12:35 PM
$tromtrooper
 
Ruggybuggy's Avatar
 
Join Date: Dec 2007
Location: Kenora, Ontario. Canada
Posts: 845
I had a tankslapper on my previous bike (KLR) at around 80-85mph. I managed to ride through it but I was very lucky. I physically shock for about 10 minutes afterwards. It started as a slight wobble then progressed to a full on wobble and I could barely hang on to the bars. I tried to gradually slowing down but it continued to all the way down to around 40 mph then stopped. I thinks what caused my tankslapper was a heavy load on the rear, not enough rear preload and to high of a speed for the bike. My new wee now has a Scott's steering dampner. I may have cost my $400 buck but once you experience a tankslapper $400 seem like a bargain. I would never ride another bike at 50+mph without a steering stabilizer.

Ask Greywolf why he uses a steering stabilizer. His story and my experience convinced me to spend the money.
Ruggybuggy is offline  
post #10 of 28 Old 04-13-2008, 12:40 PM
$tromtrooper
 
Join Date: Jan 2007
Location: Fremont, Calif.
Posts: 2,208
you'll know you're having one because you'll pucker so back you'll rip the cover off the seat.
TouringDude is offline  
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Stromtrooper Forum : Suzuki V-Strom Motorcycle Forums forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in










Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome