Does anyone know anything about tankslappers? I've seen very conflicting information about what causes them and how to correct them.

I've seen wheelies where someone at high speed puts the front wheel back down not pointing straight ahead, and that starts one. I think I understand the physics of that one.

But then I see people talk about low speed (20 mph) tankslappers that are caused by some kind of harmonic frequency of something or other. Have never had one of these, and maybe the 14 is protected against them with the suspension system (?).

Then you get into recommendations for stopping them once they've started. I see:

• Speed up
• Slow down
• Press the rear brake

But the real question I have is this: aside from changing your speed, is it best to wrestle with the bike forcefully to try to stop it, or to relax and let the bike straighten itself out (if it will?).

For many/most things, I think the more relaxed you are the better (i.e., steer the bike into a corner and then relax and let it do what it wants to do, subject to your corrections). But a tankslapper may be an exception to this rule, and may require some force.

Any thoughts or experiences with this? -bg

* Last updated by: bgordon on 2/17/2009 @ 9:26 AM *

I've experienced a LOT of high speed wobble when I had a 1989 Concours. When fully loaded with a few day's gear I could get to wobble easily by sheer straight line speed (over 100) or pushing it in a corner. That wobble would easily turn into a tank slapper if I let it. Keep your hands on the grips and let your arms take the shock of the wagging bars like a motocrosser lets his legs take the shock of going over the bumps. It also used to happen with my Blackbird on occasion due to worn tires, old fluid in the forks, loose steering head bearing.....who knows. I've heard a lot of reasons. But with the XX, with a well used front tire, I could give the handle bar a good solid shove forward on the right or the left at any speed and get the front end wagging like a dog's tail. By holding the grips and taking the shock in my arms, it simmered down BUT it looked really bad to others around me (or in front of me watching my head light shaking like HELL).
It's REALLY violent when it really gets going.
Now with the 14....I've tested that the same as the Blackbird and so far....solid as a rock.
I can't make it do anything it shouldn't.

* Last updated by: gumbybob on 2/20/2009 @ 3:56 AM *

Thanks for the information. I'll know how to handle it if it happens now.

Appears that the 14 is pretty well engineered to protect against this, then.

I notice that at the Texas mile, they require that you have a steering dampener. Seems like they cost about $400 or so. Safety measure for very high speeds, I guess. -bg

Looks like a tank slapper about 12 seconds into this one. Nothing much to watch after 30 seconds.

Don't try this at home... -bg

* Last updated by: bgordon on 2/24/2009 @ 11:20 AM *

I don't have a dampener ,,but I think they could be a cheap investment considering what can happen.

Steering dampner was the best mod I added to my R1. No more tank slaps and gives much better feel of handling of the front tire. Best to keep throttle steady when it happens if possible and relax and weight the front end.

I took a nasty tank slapper at Riverside with something called a Japauto frame. Twitchy and if you didn't ride to see where in transition the front comes off of that foot pegging dragging angle, you steer it; she over corrects, then I guess it comes around and under corrects another way. It is so fast and violent, I had my hip socket send my leg back to LA county and I was in Riverside county at the time.
I can get up off the potter, and I'll be gimping for days she has some pain going if I catch it wrong. Other times you have time to catch it, (a wobby). And I must confess, I've crashed on others rides I've caught in my career (your addiction is desperate). Using my own equipment, I've hardly crashed on the ones I used to race. I had my rotation rides during the years or midyear swap just having fun racing them.

So, say the ones you have time to catch and get out of, you stand on the pegs and stop the pendulum energy moving your own body with each ricochet. Your body is now moving the energy instead of your knees taking the cushion or that back and forth fork swap motion.

Straightaway wob's is to let the hands go, (ultra light touch). Once again you are fighting the energy and the faster it takes itself out without your help, the sooner you are back in control.

* Last updated by: Hub on 2/24/2009 @ 2:31 PM *

From personal experience(on my beloved zx12),It was THERE one second,and GONE 5-8 seconds later-no time to do ANYTHING except wonder"what the hell just happened?" and thanking God for pulling me out of it!!One second longer and the bars would have ripped out of my hands(I wasn't "holding on" at that point).Scary stuff-fortunate to make it through!!(80 mph uphill curve-35 degrees out-opening her up on the exit)