After reading Bone Head 311's account of his accident, I had to find out what causes this. A coworker gave me the best explanation, since he actually experienced it on his BMW last year. The following video details a typical tank slap event:

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The following video details a typical tank slap event:

I disagree. A typical tank slap event ends up with the rider on the ground. :(

What I meant was "typical" was the front tire coming down and "not" being straight; thus, producing the tank slap as it tries to recover. :eek:

since he actually experienced it on his BMW last year.

Do you know which specific BMW model your coworker owns? I ride with many BMW owners of pretty much every model they've made in the past decade or two, and none of them are prone to tank slappers in any way. They use exceedingly conservative steering geometry, for better or for worse, that along with the telelever front end design make tank slappers rarer than a rainy day on SoCal. :) I'd be curious to find out what happened to the guy, and what caused it on his bike?

BTW - the reason that the guy on the vid was able to keep going instead of losing it is the steering dampener caught the slapper after only 2 or 3 oscillations, and in the meantime he didn't force the bars in one direction or another to try and stop it himself (physically impossible at those speeds with that much force being transmitted from the road to the front end).

Alex,

I don't know the series, but he did say that the damper has 3 settings...off (which it was set to), on (mod firm), and on (very firm). He was riding in the twisties was coming out of a right hand turn. He had just straightened up. The pavement was wavy vvvvvvvvvvv as in grooves and he lost it. Insurance totalled the bike ($6K damage) and paid him off. He repaired it and it's OK, now, except for the tank indentations. Cost him $1900 to replace his riding gear....slid on his back for 200 feet and his armor wore within 1/2" of his skin. He actually stood up and watched the bike slide....stand up.....flip in the air and come down upside down. Damage (sliders) would have been minimal had it not flipped! Since it is carbureted, I want to say it's a late 70, early 80 model.

well, I have no clue what mine looked like, but I was able to get out of a tank slapper the second day I had my bike, unfortunately, I couldn't get out of the object fixation that followed and ended up running into a fence :(

I was making a left-hand turn off of a rural road that drops about feet in the feet leading up to the stop sign. The road I was turning onto had a 45 mph limit, though folks are usually speeding a good bit there, and the stop sign is slightly hidden at the end of a long curve. To further compound things, there was a ridge where the pavements meet, and a good bit of gravel just to my left that I didn't notice at the time... the road was tar and gravel, and upon subsequent inspection of the site, i realized that the gravel part had been kicked out to the sides, leaving only tar where I was stopped. As I hadn't really heard or thought about shimming at that point, the bike was terribly lean and rather erratic when trying to take-off from a stop.

All of these factors led to a tank slapper when I got onto the road - but hey, I didn't stall that time :rolleyes: - I was terrified, but managed to get it under control after the third oscillation or so.... I think if I hadn't fixated on that fence post (it was the corner) I would have come out of it just fine.... but all the if-onlies don't change a thing sadly :(

Good news is that a few months of healing time for the knee and some great getting-to-know-you sessions with my naked girlie, everything turned out just fine, and now I know her so much better than before ;)

Leaving base the other day, I guy on his cbr got a wild tank slapper. I was a amazed he didnt go down.......

He wasnt going over 30mph, road was wet & he got on the front brakes. I know he had to go clean his shorts afterwards :eek:

That's a crazygonuts video! As soon as his back went one way and the front the other like that it wasn't going to end well :p

This guy wasn't quite so lucky:

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But this guy is one of the luckiest I've ever seen. Not quite a full-fledged slapper, with just 1 or 2 oscillations, but what a save:

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Alex,

I bet the fellow in your second video probably challenged the other riders to beat his "trick riding" demo, like he planned that!

You obviously looked at the other videos, after watching the original one. This Isle of Man one has another view showing the emergency crew trying to help him on the track. One fool (holding the yellow flag) even walked at a bike like he was going to personally stop the biker, if he didn't move over.

Wow those look scary!

Instead of recovery techniques, what can you do to help prevent a tank slapper?

Our ninjettes aren't particularly susceptible to tank slappers. Keep your tires aired up, make sure they aren't in horrible condition, make sure your suspension is working as it should, make sure your steering head bearings aren't way over or under tightened and it's very unlikely you'll ever experience one. While there are posts on this board and related boards that people have had tankslappers on a stock ninjette, frankly I don't believe them and think they experienced loss of control for a different reason. I would probably have to experience it myself or see someone else experience it to change my mind. :2cents:

I have seen a friend of mine have a terrible lock-to-lock tankslapper on his older Honda 954RR that he had done a bunch of suspension work on; he was able to ride it out and gain control. Was right behind him at the time, and it was quite a show. In a weird coincidence, he was behind me a few years later when I had a similar experience while accelerating on bumpy pavement on an R6. That was a very twitchy bike, and probably should have come from the factory with a dampener (they now do). Our ninjettes do have a very light front end, with a light wheel/tire/brake/fork assembly, but the geometry is still so conservative that it's surprisingly stable. Which is a good thing! :)

I've seen that second video that Alex posted before. What a crazy ride. Its good to have skill, but I'm sure luck played at least a small part in that :)

Our ninjettes aren't particularly susceptible to tank slappers. Keep your tires aired up, make sure they aren't in horrible condition, make sure your suspension is working as it should, make sure your steering head bearings aren't way over or under tightened and it's very unlikely you'll ever experience one. While there are posts on this board and related boards that people have had tankslappers on a stock ninjette, frankly I don't believe them and think they experienced loss of control for a different reason. I would probably have to experience it myself or see someone else experience it to change my mind. :2cents:



On the other site, I remember reading a thread about tank slappers and there were an overwhelming amount of people who replied with "yeah I had one the other day" and "yeah I had one 2 weeks ago." I'm not exactly sure these were 250 riders, but I was shocked at how common they were (as it seemed after reading that). It's a little better to hear now that they may not be as common as I had originally thought, regardless to the type of bike.

Thanks for the tips.

So, I'm not gonna lie, I got close to having one because I was being dumb, but I did a 250r wheelie in a parking lot and came down with the front tire turn a touch.

I'm by no means an experienced rider and I should have gone down (even though i'm 90% of the time super-mega-ultra-turbo-paranoid about riding), but it straightened out and I rode off shaking.

Those are some impressive little vids right there. Would be scary to go through that.
During one of my rides over the summer I had a little bit of a steering wobble. I was probably going a little over 60mph, but at that point the road was really bumpy. It completely freaked me out when it first happened, so I loosened my grip and let off the throttle to let the wobble run its course. I'll admit that probably happened more out of chance than intention because it happened so suddenly and scared me. The whole ordeal didn't last more than a second or two. But it definitely was no where near as crazy as what happened to those guys, the bike, except for the handlebars, kept itself very stable throughout.

When the front end wiggles, it's called headshake. When the entire bike start to oscillate wildly back and forth as in the vids, that's a tank slapper.

funny you should have headshake, though. What is your rear shock preload set to? I've never had headshake on my 250R. :confused:

i'm 99% positive the preload is on the softest setting. I'm only a little over 140 lbs, and I never carry any passengers, and hardly ever any luggage. It's only happened to me once, and I've ridden that road at least 5 times since I got the bike (what can I say, it's a nice road). I really think it was just a bunch of freakish coincidences. Also, when I say bumpy, I mean ridiculously bumpy, you don't even know what frost heaves are down there in Hawaii :p But here, they form and then they don't go away with the coming of spring.:rolleyes:

I really think it was just a bunch of freakish coincidences. yes, headshake can occur under the right conditions, though as I said, the 250R is set to pretty conservative specs to make the bike new rider friendly. I would have to agree your instance was a combination of the right elements being there together at the right time for the headshake to occur.

stay safe.

stay safe.

Thanks Kelly. I will. :) I wasn't riding aggressive when it happened either. I don't have enough miles ridden yet for me to even start pushing the bike. At least I know what to do though.

learning new stuff everyday, I just think the term "tank slap" is funny