Tankslappers explained

**dpex** · 15th September 2008, 19:41

I think that guys who ride Harleys are genuine tank-slappers.

Today I stopped at the lights beside a Harley man.

'Great day, Huh?'

'The best.' And it was.

'Your bike good in corners?'

'Mate. Harley's don't corner unless you're really strong.'

He smiled. The lights turned green. I offered him first off and watched him round the corner like a dancer with a really big stake up her bum. Placed a slight extra weight on Yami's inside peg and down she went...Elegance compared to force.

But geez. They sound good, huh?

**racefactory** · 18th September 2008, 13:57

Originally Posted by motorbyclist

that post is an absolute load of bollocks, relying on bullshit to justify it's pseudoscience. the original post back in 2006 was much better

first of all, they can happen at any speed

next, hitting the gas and thus removing weight from the front and stiffening the chassis is a very effective way of stopping tank slappers. while i'm sure in some rare cases the geometry of the bike, degree of slapping, and power of engine may conspire to make this worse i've always found it to be successful - and if you gas enough so the front wheel ain't on the ground it isn't going to "slap"

the absolute worst thing you can do is hitting the front brake

a good idea is to relax your grip on the bars - often it is you that is making the oscillations worse.

tankslappers usually arise where the front, for whatever reason, has come out of line with the rear wheel and the rear is still (more or less) in line with the momentum of the bike, ie, not drifting.
say the front has jumped left - the bike's momentum wants to keep going forward. the traction of the tyres will now exert forces to correct this, by leaning and steering slightly to the right, but of course if the wheel doesn't straighten fast enough it will overshoot, and now be on the right of the bike's trail as the bike starts to lean left as the wheel runs out from under it to the right. wheel comes back around and if you're unlucky it'll overshoot again. sometimes it'll do so in such a way it gets worse and worse and before you know it the rear wheel is getting flicked around too, you've been thrown off the bars, and there's a fast approaching tree. if you want to test this, go down the motorway and give the handlebar a good nudge on one side, you'll notice the bike oscillate a few times before getting straight again (i'm not accountable if you have an accident doing this obviously dangerous test)

holding on tighter will not help unless you are a human supercomputer capable of applying forces to cancel out the oscillations of the handlbars. you will usually only make it much worse much faster

front brake just puts more weight on the front, pushing it further past the neutral position (so it'll overshoot more) and make things worse.

loosening your grip will save you being thrown off the bike, and let it sort itself out

rear brake can help change bike geometry, and stiffen the chassis.

hit the gas instead and the bike stiffens, geometry changes (including an increase in rake angle, which is exactly what you wish you had right now; when was the last time a chopper got a tank slapper?) and the weight all comes off the front wheel, allowing it to get back in line

of course this also speeds you up, which is not good in a crash and as such is rather counterintuitive, thus we have the ramblings of the bollocks post

but, if you've ever ridden a dirt bike you'll already have this "if in trouble, pick up the front" instinct nailed ever since you first hit the brakes on coming across an unexpected gully/ditch/drop/woops/jump and got a face full of dirt

dude! not only is that the only dampener i've ever seen in that position, but how could you not see that being a hazard while riding?!

This is good but you seem to have covered everything but body position. Can we just infer that as the main goal is to have the WEIGHT OFF OF THE FRONT, therefore we should be not leaning forward so much and instead be sitting more upright and back?

**motorbyclist** · 19th September 2008, 21:28

Originally Posted by trademe900

This is good but you seem to have covered everything but body position. Can we just infer that as the main goal is to have the WEIGHT OFF OF THE FRONT, therefore we should be not leaning forward so much and instead be sitting more upright and back?

i just sit wherever is comfortable (nc30 will sort itself out), though i do notice i gradually move forwards on the seat as the tank empties out....

**The Lone Rider** · 14th January 2009, 23:53

Dang, I didn't know there was already a term "tank slappers"

For the past year or so, I have been referring to a lot of motorcycle girls I have met through motorcycles, as tank slappers. Mainly due to them being of the "groupie" nature and passing themselves around - good time... not long time.

Not my thing, not into them tank slapper girls. To the curb they go when I find out their motivations!

**86GSXR** · 22nd February 2009, 14:15

I've had a couple of scary ones years ago on first generation Gixxers. But last Sunday I had the most close up encounter with one of these bitches to make me never want to encounter one again. Put me in hospital for two days and I'm now recovering from four broken ribs, a cracked shoulder blade, a badly broken hand, plus various scrapes and abrasions.

I was going up the Pahiatua track, one of my favourite roads and one I've done hundereds of times.

I was following a mate on a Sprint ST and I was on my (now wrecked) 08 Tiger.

All was normal, we were travelling at a reasonable, legal pace and just coming out of an uphill right hander onto a short straight. It was a beautiful sunny day, no wind and a completely dry road in good condition. In short, a perfect biking day.

My tyres (Pilot Roads) were warm and in decent condition. The front and rear suspension were set up pretty well for my weight and riding style.

As we rounded the bend my front suddenly let go and slid a few inches to the left. I have no idea why it slipped, maybe there was a small stone, diesel patch, slippery patch, whatever.

When it regained traction the bike started to highside me off to the left. I reacted pretty quickly and hoisted it back but by then the front and rear had become completely uncoordinated and I was in the midst of the most violent and powerful tankslapper I could ever have imagined.

I tried applying power and tried to even it out but I was helpless to do anything in a controlled manner as the oscillations were just too powerful.

The only thing I could do was to just bail off before I was thrown off. I did that and landed hard on my back on the right side doing the aforementioned damage to myself.

It's a bit of a blur after that, but apparantly my bike kept on shaking itself up the road before falling over and sliding up the road and down a bank.

Later on in hospital my friend told me that he'd seen most of it in his mirrors and I'd looked like a rag doll with my legs going everywhere. I don't remember that bit as I must have been too busy trying to control it, unsuccessfully.

I was saved by my fully armoured and well fitting leathers, which held up pretty well. My helmet was really crunched in at the front and I thank god I always wear my gear and had made a point of making sure my helmet strap was tight before setting off.

I'm in for a few weeks of pain yet though, broken bones, especially ribs are NOT fun!

Always wear armoured, snug fitting gear and do your helmet up securely PLEASE! I wouldn't wish this shit on anyone

**BMWST?** · 11th May 2009, 20:37

my Ductai S2 used headshake over railway lines etc ,only under accelleration ,hit the bump and the head would shake 1,2,3, and then be dead smooth again.

**Motoracer** · 12th May 2009, 07:25

Originally Posted by jonbuoy

Crossed up wheelie landings can trigger em too.

http://www.bikepics.com/movies/000464/

Also trying to Manhandle a rolling stoppie at speeds of say over 50kmph once the stoppie has already comenced into full 'roll' (nearing balance point). Manhandle as in trying to correct or manuver the path of the stoppie.

Another major catalyst resulting in a slapper is ofcourse, fuked steering head bearings. If they are rooted, get em fixed ASAP. Otherwise, once you hit a few bumps at speed, it could be all over!

**erik** · 12th May 2009, 07:53

Originally Posted by 86GSXR

...
As we rounded the bend my front suddenly let go and slid a few inches to the left. I have no idea why it slipped, maybe there was a small stone, diesel patch, slippery patch, whatever.

When it regained traction the bike started to highside me off to the left. I reacted pretty quickly and hoisted it back but by then the front and rear had become completely uncoordinated and I was in the midst of the most violent and powerful tankslapper I could ever have imagined.
...

Are you sure it was a tank slapper and not fish-tailing (rear end losing traction)?
The marks on the road look too wide to me to be from a tank slapper.

Anyway, get well soon.

**Chrislost** · 12th May 2009, 08:38

Originally Posted by 86GSXR

The only thing I could do was to just bail off before I was thrown off.

Thats a stuff up! Heal well!

Ya can get slappers if the back lets go briefly and comes back...

I have seen those exact marks appearing in front of me from the BACK WHEEL of a zx10 after the guy stepped the ass out on a bump and let go of the gas...

**ducatilover** · 12th May 2009, 09:48

You can get good slappers with a bros650 if you don't know how to ride very well....not the kind of slapper we all love though

**86GSXR** · 12th May 2009, 10:58

Originally Posted by erik

Are you sure it was a tank slapper and not fish-tailing (rear end losing traction)?
The marks on the road look too wide to me to be from a tank slapper.

Anyway, get well soon.

Originally Posted by Chrislost

Thats a stuff up! Heal well!

Ya can get slappers if the back lets go briefly and comes back...

I have seen those exact marks appearing in front of me from the BACK WHEEL of a zx10 after the guy stepped the ass out on a bump and let go of the gas...

Thanks. Good points guys. Maybe the back did let go, it happened so fast it's a bit hard to tell. It felt like the front, but maybe.........?

Yep, three months now and I'm still not quite right. A lot better than I was then though

Originally Posted by ducatilover

You can get good slappers with a bros650 if you don't know how to ride very well....not the kind of slapper we all love though

Give me the other kind any day

**motorbyclist** · 13th May 2009, 01:18

a few weeks ago i clipped a reflector ona right hander at 100kph - front slipped about 15cm before regaining traction at which point the rear lost traction.

spent the rest of the corner with a meeaaan fishtail but just kept riding and it sorted itself out. gotta love the NC30/NC35 chassis

**LaytonNZ** · 31st May 2009, 21:10

This Happend to me wile going down a hill i hit some tree roots i was overtakeing doing 140 kmh sceard the shit out of me:P

**6ft5** · 1st June 2009, 10:46

Originally Posted by 86GSXR

I was saved by my fully armoured and well fitting leathers, which held up pretty well. My helmet was really crunched in at the front and I thank god I always wear my gear and had made a point of making sure my helmet strap was tight before setting off.

I'm in for a few weeks of pain yet though, broken bones, especially ribs are NOT fun!

Always wear armoured, snug fitting gear and do your helmet up securely PLEASE! I wouldn't wish this shit on anyone

Good luck with your recovery mate. Have had some bad time myself and after 12 months am finally coming right.