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Discussion Starter · #1 ·
Hi Guys,

I find myself doing 125MPH or so quite often and fortunately never experienced tank slapping. Seems like everyone has their own option on how to stop it. I've heard people say hit the rear brake, hit the front brake, let off the throttle, or give it gas. Does anyone really know for sure what to do when this happens besides ride slower? :0)



Thanks,

Joe
 

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There are several things that can cause a 'tankslapper'....usually a lack of weight on the front wheel combined with poor tracking of the front tire will do the trick. You could let go of the bars and lay on the tank, the idea is to get weight on the front SLOWLY, hitting the rear brake might work if done VERY carefully (in conjunction with backing off the throttle) or if you do it too quickly you might end up in the ditch lol....

Take a look at your front tire and your front suspension, setting the suspension to stiff and a worn tire invite tankslappers with open arms.

There are lots of opinions on this subject and you will see varying advice, the one thing that everyone will agree on is don't fight it, you can't keep up with the bars.

jazz
 

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Simple answer: Wear pants so your boys don't slap the tank at 125.:joke:





What tires are you running and how much wear is on them?
 

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Discussion Starter · #4 ·
Simple answer: Wear pants so your boys don't slap the tank at 125.:joke:

What tires are you running and how much wear is on them?
The bikes an 07 with 4,300 miles on it. I have the stock front tire with a new 250 dunlop in the rear.

As posted this hasn't happened to me. The bike is very stable at high speeds. I just wanted to know in case it does happen.
 

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would a steering stabilizer help?
I have thought of this and wondered of there is one to fit the 9

I feel it unstable more so with the 280 160 combo with balance beads
over 110-135 is when I feel it

It does not wobble but I can feel it could go that way
 

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I don't think "tank slappers" are much of an issue on these big heavy cruisers with their ultra-long wheel bases.

This becomes more of a problem on very high performance sport bikes which are very light, have short wheel bases, and tend to significantly unload the front wheel under acceleration. That is why you usually see steering dampers fitted to high end sport bikes. This damper essentially acts as a shock absorber for the handlebars and slows down the frequency of any oscillations should they occur. I have yet to hear of anyone experiencing a tank slapper on a well-built 700+ lb cruiser.



If you're not familiar with the term:

Per Wikipedia
Wobble, shimmy, tank-slapper, speed wobble, and death wobble are all words and phrases used to describe a rapid (4-10 Hz) oscillation of primarily just the front end (front wheel, fork, and handlebars). The rest of the bike remains essentially unaffected. This instability occurs mostly at high speed and is similar to that experienced by shopping cart wheels, airplane landing gear, and automobile front wheels. While wobble or shimmy can be easily remedied by adjusting speed, position, or grip on the handlebar, it can be fatal if left uncontrolled.

Wobble or shimmy begins when some otherwise minor irregularity, such as fork asymmetry, accelerates the wheel to one side. The restoring force is applied in phase with the progress of the irregularity, and the wheel turns to the other side where the process is repeated. If there is insufficient damping in the steering the oscillation will increase until system failure occurs. The oscillation frequency can be changed by changing the forward speed, making the bike stiffer or lighter, or increasing the stiffness of the steering, of which the rider is a main component.
 

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My old 750 kawi triple was fitted with the steering stabilizer. And it needed it, 1974 was a while ago for safety/engineering technology on bikes, My arms got real strong riding that bike.....
 

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Bad situation, the only way out is to goose it
 

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One day in 1981 I borrowed my dad's 1975 Honda CB-360. While riding at over 70 mph, all of a sudden the bars started oscillating, not hitting the tank, nut hitting the steering stops. When I rolled off the throttle to try and stop it, I found myself airborne, flying through the bikes windshield, and crossing from the left lane to the right. I had been riding in the left lane, and ended up landing in the right lane in front of a car that was slightly behind me. Fortnately he was paying attention and avoided hitting me.

Later analysis of the bike showed the swingarm bushings to be bad. In those years most Japanese bikes came with plastic swingarm bushings, which did not really last beyond 5,000 miles. It was best to replace them with aftermarket metal bushings, which I had done on my bike at the time.

Anyway, if the "tank-slapper" is caused by something in the back, you have to add gas, not reduce it. Or that is what I was told at the time. Really, when it is happening to you, there just is not much time to think or react.

Imagine yourself the rider of the bike in the vid Kev posted!:eek:
What would you do?????????????

Been there, done that. Hoepfully never again.
 

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This was a REAL problem on my 1997 VMax. Scared the Shyte out of me a couple of times. I can't even imagine this would happen on the 9 due to the long wheel base. These bikes are VERY front heavy which usually stops this from happening.
 

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Hi Guys,

I find myself doing 125MPH or so quite often and fortunately never experienced tank slapping. Seems like everyone has their own option on how to stop it. I've heard people say hit the rear brake, hit the front brake, let off the throttle, or give it gas. Does anyone really know for sure what to do when this happens besides ride slower? :0)



Thanks,

Joe
:joke: Well one thing that you can do is get a girl friend...I've heard that helps with meat spanking.....:eek:....You mean tank slapping sorry...:redfaced:
 

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Watch the video again a couple times and pay particular attention to the rear wheel while all the slapping is going on. Also notice the rider's riding position with feet-out stabilizing position. Probably the wrong reaction to correct this situation. Unfortunately, and for probably most of us, this is a natural rider reaction to a situation like this. This allowed the rear of the bike to resonate with the front of the bike without correction until it collapsed.
Studying the video it would seem that applying rear break in this particular situation may have slowed the oscolation allowing to eventually correct the situation.
What's your thoughts?
 

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As others have mentioned1 i dont think it is really a coincern on these bikes. I have had many over my time on the sport bikes and besides just plain praying I would grip the tank with my legs, lean forward, ride it out and hope for the best. I saw a video once and I did a search but could not find it but the rider with a on board camera was getting on iot and started to tank slap pretty bad so he rolled on the throttle and just pulled that front wheel up and then set it down like he meant to do it. I think the turbo on the bike might have helped a bit but very impressive non the less. Dont thik we are doing that with ours however.

Juice109
 
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