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Discussion Starter · #1 ·
I'm lying here with a cracked pelvis, fractured wrist and quite a bit of road rash, wondering if anyone has any ideas why I had a tank-slapper on my 2006 SportClassic 1000? The conditions were not what you'd normally associate with a tank-slapper: warm sunny day, straight smooth well-surfaced road, cruising at a steady 120 km/h (75 mph). I remember the bars oscillating once, then much more fiercely, then very fiercely a third time, and I was on the tarmac. No warning signs. Had enjoyed two hours of mountain passes with no hint of trouble. Been riding for 48 years and never experienced anything like this. Not had a chance to inspect the bike yet due to prone status, but am told there are no obvious mechanical issues. Any ideas?
 

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Peter, sorry to hear you took a fall...

The slightest bump, pothole or small road debris, especially those unnoticable to the naked eye at 75mph, can be enough to initiate a tankslapper. I've been working on a short video that goes into greater detail on this topic, and from your explanation it sounds like you may have hit an uneven patch on the road (I'm just guessing)--and the rest is history. There are many other scenarios that will cause a tankslapper, but from your description, none of those would apply.

Was this incident recorded? If so, we could analyze it better if you could post the video here. Also, I'm curious: Do you have a steering damper/stabilizer installed on your bike? I had a really violent, but short, tankslapper on the track a while back and I credit my GPR Stabilizer for saving my a$$ that day.

Get well soon!
 

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I have a GT not sure if there is much difference in the frame geometry between the two, you may have the lighter wheels, slightly better suspension, but while they are great fun to ride I don't find the handling to be exactly confidence inspiring.

I do push mine very hard and have had a few moments myself...

Very sorry to hear about your mishap...
may just have to chalk it up to the shit happens category
 

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Discussion Starter · #5 ·
Thanks for your responses, guys. No, I don't have a video of the incident (wish I did) and I don't have a steering damper or stabilizer fitted. Oddly enough, I also own a 1997 Suzuki TL1000S, which was notorious for tank-slappers. Mine has a Maxton suspension conversion, which allows the bike to handle just fine without a steering damper (which I still have). I had ridden the TL over the same route only a few weeks earlier. I'll check out the Ducati for mechanical failure when I'm well enough to make it downstairs to my garage, but in the meantime I guess I'll settle for a combination of an unseen road imperfection combined with "shit happens". Still love the bike, anyway...
 

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Yeah, sorry to hear about your off, man. I'm kinda in the 'road irregularity/pothole' group. I'm also a believer in steering dampers. I've had my bacon saved more than once, both on and off track by them. I also wonder just how soft you may have had the front end setup....the road defect causing the fork to blow through it's full stroke and bottom, could also have contributed to amplifying the first twitch.
Just a few thoughts....get well fast and get back in the saddle.
 

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Unfortunately this model is not set up terribly well for this type of contingency.

A steering damper (if not fitted) is certainly worth considering, but will only deaden a tendency they have - largely due to their use of spoked wheels, with relatively wide tyres.

Presuming yours has the spoked wheels - these are HEAVY. Once those sort of oscillations have started - probably initiated by encountering a bump or pothole which has affected one side of the tyre more than the other - the weight of the wheel makes that worse, and harder to 'catch'.

Lighter wheels, and a steering damper, are the solution. Many have gone this way with these 'retro' models. Not just to make them more sporting, but also to make them safer..

Owners say "but I rode bikes with spoked wheels for years". As of course most of us did. But the spoked wheels on these, combined with fat tyres, heavy single-acting calipers etc. make for a very heavy 'unsprung mass'.

This, in combination with a reasonably light bike has meant that once the oscillations commenced, you had a reduced ability to hang onto it.

Of course this theory presumes there was no other mechanical problem with the bike pre-accident.

I hope you heal satisfactorily, and soon. Be patient, and do the exercises (my many years working in rehabilitation coming through..). Hopefully you will want to, and be able to, return to riding.

Maybe the accident repair to your bike could include the mods suggested. Upgraded forks, calipers and wheels.

Many S/H parts offered on here from more serious sports models.. I'm guessing you'll have plenty of time to go on-line and check them out..

All the best mate. I have done many months in hospitals before I started working in them.

:(
 

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+1 on the damper. A few years ago I hit a big stick (I'm assuming that's what it was; I never saw it but I was riding an unlined mountain road immediately following a wind storm and there was shit everywhere:rolleyes:). Anyway, it was like a week after getting one installed and to this day I'm convinced it's the only reason I held on. Both my feet came off the pegs, the bars snapped back and forth at least twice, and most of my weight (also probably luckily) went over the triple for a second or so. Scared the crap out of me and I wasn't even going fast...:eek:

Get well soon.
 

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Sorry to hear... get well soon!

I Googled Tank Slapper. It is a speed wobble... Why is it called a 'tank slapper'? Doesn't sound like anything to do with a 'speed wobble'. I know it's going to be something obvious... :(
 

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When the handlebars oscillate and that oscillation increases, the handlebars slap the side of the tank back and forth.

When this happens, kiss your ass goodbye.
 

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Thanks for the explanation Johnny...

Can any bike be fitted with a steering damper... such as a Multistrada? Sounds like a 'must-have' mod...
Motorcycles have been around quite a while without them. I would say (I) that it is a bit unnecessary for the average rider. Yes as I said earlier, shit happens. But hell if we wanted to spend money endlessly we can always buy full leathers with airbags helmets with airbags...

Sure nice to have but we cannot protect ourselves from every possible unexpected gremlin out there.

So yes nice to have... do we all need them???
 
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Many of the current 'standard' style bikes are coming with more aggressive geometry than bikes used to. Rake is steeper (closer to vertical) and trail shortened from what was even recently the norm. It's made for some truly remarkable steering/handling motorcycles, but it has also made them twitchier than not. Out and out cruisers never experience this sort of accident, due the shallower rake and longer trail of their chassis.
 

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Here's another good example from a local guy, who also managed to save it. I have an Ohlins steering damper on my 1198 which has saved me from that numerous times. Most modern bikes come with them nowadays, and a lot of the Ducatis come with some cheap one that's better than nothing, or Ohlins in the case of the S models. I bet Multis have them as standard...shit, they have everything else on now, including cruise control!!

 

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I always wondered why it's called a tank slapper too....I always assumed it was because usually when it happens you end up high-siding and the tank slaps the ground like you wouldn't believe! :D
 
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