Lucky escape

[grimey121uk]

Had my first tank slapper today, was turning right on a large motorway which leads to a slip road for the m61, as i was exiting the roundabout the back wheel started to wheel spin and the back end drifted out a long way and then my bars swung violently side to side about 5 times,

Road was slightly moist

luckily i managed to stay on,

Not sure if i hit a patch of oil/diesel as very strange as i wasn't even going fast, I was riding slower than a do in the pouring rain.

Just a warning to people in this damp weather

[Stu]

It's great fun - gives you a buzz :D

Well done for riding through it

[Geodude]

Glad you stayed right side up. Ride safe.

[speedplay]

Tank slap makes you feel alive :)

[davepreston]

im sorry sir but you seemed to have failed the brown trouser inspection, but on the positive side you pasted the dont flap and feck up section

[Ed]

Well done you. More detailed analysis required please of what happened and how you reacted and how you treated the controls (if you can remember, I guess it was all over in a nanosecond).

[hongman]

Not had a tank slapper on the SV yet, not looking forward to the day I do lol.

Glad you be safe

[Specialone]

Well im a wimp then, cos any loss of control like that scares the crap out of me :( except on my DRZ where i dont care as much.

Well done btw for keeping it together :)

[The Idle Biker]

Pleased you made it through. Reminded me of an incident with Randy Mamola back in the day blah blah. Atta boy Randy. Click on link.
http://www.youtube.com/watch?v=XaQGI8GSVJM (http://www.youtube.com/watch?v=XaQGI8GSVJM)

[Mr EnDo]

I have had a few ones on country roads and managed to stay on, scary and a rush at the same time, had one as I was breaking for a round about and didn't see the diesel spill on the road and rear locked had to miss the turning and go back around, most scary as a car entered the round about as I was trying to stay upright.

[Fluffer]

What is the actual way to deal with these? Happened to me mid dec on the one good day between the snowfalls, road was wet and rear tyre was new so putting power on coming out of a roundabout and back wheel came out and I wobbled for what felt like eternity.. Stayed up but on reflection not really sure how...

[tom-k6]

i had a cool looking one yesterday in birmingham city centre, just turning left onto a main road and mid-turn, my back tyre started spinning and i think i slipped on a manhole cover, but it looked like a mini-drift at like 12mph. felt like B.A.Baracka's :D

[Reeder]

i had a cool looking one yesterday in birmingham city centre, just turning left onto a main road and mid-turn, my back tyre started spinning and i think i slipped on a manhole cover, but it looked like a mini-drift at like 12mph. felt like B.A.Baracka's :D

Haha, I had a little tail slide the other month. Was greasy roads and was leaving work so I was driving around the industrial estate. Just turned left onto the road leading out and started over taking a couple of cars straight out of the turn as it was clear ahead. Lost all grip at the back and did a little drift thing past them! I **** myself :)

[Jimmy2Feet]

We have all been there, or will be one day. i have had a couple of dodgy moments, but the worst for nearly loosing control was just after i passed my test, and it was my first or 2nd trip to Poole quay (a big old weekly bike get together for the non locals) and me being young/naive and stupid, was trying to keep up with GSXR600, bandit 1200 & a fazer thou i think it was, on my little SV still restricted to 33BHP!! came to a roundabout, with far to much speed, hit the breaks far to late, locked up the back wheel, front started to wobble......everything went into slow mo, but somehow managed to end up at the front of the roundabout after filtering past several cars (not sure how many maybe 4/5) with everything pointing in the right direction to be able to slowley pull away from the roundabout and preceded to go slow and steady the rest of the way to the quay......i met the others there!!! :)

[Stu]

What is the actual way to deal with these?
It's all Voodoo & witchcraft :-$

[MattCollins]

Hang on and don't give in. 9 times from 10 you'll survive the worst of them.

I still remember my first big tank slapper circa 1978... Landed a jump (more like a big whoop with a lot of air) and broke a shock as I gave the beast a big fist full. The thing started bucking like a mule at both ends with the bars going from lock to lock as I am heading straight at a huge stump from some ancient tree. At one stage my feet were above my head. I managed to hold on and bring it all together, but I was sore for a week after the beating that the bike gave me.
The big GS demands to be ridden hard off road (80kph minimum and a lot of throttle on sand, 90-100kph about right when loaded), but it likes to give its head a good shake every time it tops a dune or big whoop if the damper is not set. Nothing particularly dangerous, but unnerving the first time. Just one of the joys of riding.
On the road, I've never really had a bike do much more than wriggle around and shake its head a bit.

[hongman]

I think its a much debated subject, some say give it some throttle, some say ease off a bit, some say keep it cracked on.

Chances are though, when it happens you will do whatever your instinct tells you to do, becuase it's happening so quickly (and over so quickly generally)...

I guess experience helps to keep the panic levels down, but unless you want to go and try recreate a slapper, just keep on riding I say!

[Stig]

Had a couple in my time. But the best one I've had I wasn't even riding. Was on the back of my mates bike. He rode over a railway crossing and got a bit of air time from the front wheel. He went over the crossing not quite straight and we were heading for oncoming traffic. He forced the bars to steer before the wheel was back on the ground. It was as the front wheel hit the road with the steering twisted it started to shake. I have an idea it was the additional weight of me on the back that helped the bars start to slap rather than the gyroscopic effect to happen and straighten the bars back out. Well we went down the road with him fighting with all his might to regain control, but the harder he fought, the worst the slapper got. Eventually he gave up and just let go of the bars altogether. Almost instantly the bars settled down, he grabbed them and wound the throttle back on again.

What I didn't know was that when he let go of the bars, he was actually getting ready to depart from the motorcycle. It was only because when he let go the wheel came back to centre that he changed his mind and stayed on. :lol:

Another time he got a slapper was when going through some road works, he thought it would be a good idea to kick a traffic cone over. I don't think he realised just how heavy one of those are and gave it a kick as he went passed. As his foot made contact with cone, he was almost dragged off his bike, which caused a tank slapper. Was the most funniest thing I had seen in ages. I nearly had to stop riding myself as I was laughing so much. Believe me, it was one of those 'had to be there' moments. :lol:

[tom-k6]

Another time he got a slapper was when going through some road works, he thought it would be a good idea to kick a traffic cone over. I don't think he realised just how heavy one of those are and gave it a kick as he went passed. As his foot made contact with cone, he was almost dragged off his bike, which caused a tank slapper. Was the most funniest thing I had seen in ages. I nearly had to stop riding myself as I was laughing so much. Believe me, it was one of those 'had to be there' moments. :lol:

HAHAHAHAHAHAHAHA :winner: i wouldve loved to see that, ive come close to some cones and ive had the misfortune to be working collecting those cones they use on the motorway, they are bloody heavy, made up of old tyres for the base

[metalangel]

What I didn't know was that when he let go of the bars, he was actually getting ready to depart from the motorcycle. It was only because when he let go the wheel came back to centre that he changed his mind and stayed on. :lol:

http://upload.wikimedia.org/wikipedia/commons/6/6b/Ejectionseat.jpg

[-Ralph-]

I think its a much debated subject, some say give it some throttle, some say ease off a bit, some say keep it cracked on.

Don't even go there on this thread, or we'll end up with a whole load of crap advice given to a whole load of people for whom it is not relevant.

The reason advice on recovering from tankslappers is not relevant, is because although the OP may have had the bars slapping against the tank, he didn't have a "tankslapper", he lost traction at the rear wheel and nearly got highsided.

A "tankslapper" is an oscillation caused under hard acceleration in a straight line, with the same end result of the bars slapping against the tank, and it is caused by the rear shock. MattCollins is the only description on this thread who had a "tankslapper". The SV doesn't really have the power to create a tankslapper, but if you get it on full throttle about peak torque (8000 revs or so) on a bumpy road, and the front end starts to wag the bars gently from side to side, that is the beginnings of a tankslapper, if you had more power and were still using full throttle, a tankslapper would probably develop. Remember the standard SV rear shock is s**t.

Stig said "Eventually he gave up and just let go of the bars altogether", and this is pretty close to the best advise for the type of bar slapping that most people on here are describing. The bike wants to reach equilibrium and run straight. How many times in racing do you see the rider get thrown off by a highside, then the bike wiggles along like a fish, straightens itself out completely and runs across the track into the gravel, on it's own in an upright position. Anybody remember this thing? http://www.youtube.com/watch?v=HYwXAXw5WYE&feature=related With only two wheels how did it remain upright? Exactly the same way a motorcycle does, only it doesn't have a human being sitting on top of it.

If you get into a bar wagging situation, caused either by a slide at the rear, or by the front wheel landing badly off a wheelie, don't try to correct it yourself, hands off (not literally, just lighten your grip on the bars) and let the bike sort itself out, buy making inputs yourself you will only make it worse.

[Jimmy2Feet]

Don't even go there on this thread, or we'll end up with a whole load of crap advice given to a whole load of people for whom it is not relevant.

The reason advice on recovering from tankslappers is not relevant, is because although the OP may have had the bars slapping against the tank, he didn't have a "tankslapper", he lost traction at the rear wheel and nearly got highsided.

A "tankslapper" is an oscillation caused under hard acceleration in a straight line, with the same end result of the bars slapping against the tank, and it is caused by the rear shock. MattCollins is the only description on this thread who had a "tankslapper". The SV doesn't really have the power to create a tankslapper, but if you get it on full throttle about peak torque (8000 revs or so) on a bumpy road, and the front end starts to wag the bars gently from side to side, that is the beginnings of a tankslapper, if you had more power and were still using full throttle, a tankslapper would probably develop. Remember the standard SV rear shock is s**t.

Stig said "Eventually he gave up and just let go of the bars altogether", and this is pretty close to the best advise for the type of bar slapping that most people on here are describing. The bike wants to reach equilibrium and run straight. How many times in racing do you see the rider get thrown off by a highside, then the bike wiggles along like a fish, straightens itself out completely and runs across the track into the gravel, on it's own in an upright position. Anybody remember this thing? http://www.youtube.com/watch?v=HYwXAXw5WYE&feature=related With only two wheels how did it remain upright? Exactly the same way a motorcycle does, only it doesn't have a human being sitting on top of it.

If you get into a bar wagging situation, caused either by a slide at the rear, or by the front wheel landing badly off a wheelie, don't try to correct it yourself, hands off (not literally, just lighten your grip on the bars) and let the bike sort itself out, buy making inputs yourself you will only make it worse.

Very sound advice, as long as your going above 25mph (i thihnk it is i am sure i will be corrected) the forces that are placed on the bike will allow it to keep rolling in a straight line without human interaction, and without dropping. therefore if the bike starts to wobble, letting it do its own thing it should correct itself.

It is simple physics, everything in nature will always try to take the most simple rounte, and in most cases this is straight lines,

[Stig]

I thought it was called the gyroscopic effect of the front wheel which brings it back into line.

Everyone refers to a tank slapper as the bars moving from side to side. It's a geralisation really. I've had one tank slapper on my old CBR600. Accelerating out of a sharp bend in the middle of a dip. Throttling out of it whilst the suspension at the rear was still in compression state. Fortunately the old CBR600's were very forgiving motorcycles to ride, and it just sorted itself out without any necessary input from myself.

[yorkie_chris]

This is a fishtailing type incident which is as much luck as management to not book a short stay in the highside hotel (nice view but the food's sh*t).

Recovering is a case of not whacking the throttle shut when the back end steps out, as this guarantees a highside. You need to close the throttle a bit but not all the way to allow it to regain grip.

[Stig]

This is a fishtailing type incident which is as much luck as management to not book a short stay in the highside hotel (nice view but the food's sh*t).

Recovering is a case of not whacking the throttle shut when the back end steps out, as this guarantees a highside. You need to close the throttle a bit but not all the way to allow it to regain grip.

If that's refering to me, I don't think the rear went loose at all. Certaintly didn't feel like I was losing any traction. I just pinned the throttle and it sorted itself out. The bars shook violently but sorted themselves out very quickly. The back end as far as I was concerned was planted and providing me with all the grip I needed. It was the front doing the wiggling not the back.

[Stu]

If that's refering to me,.
no he meant OP (imo)

[-Ralph-]

I thought it was called the gyroscopic effect of the front wheel which brings it back into line.

I don't claim to understand the physics, but had it explained to me by those who do, and yes, gyro effects are a large part of it, but it's not quite that simple because a motorcycle is not a rigid assembly like the Evil Knevil toy, so movements in the headstock, swingarm, forks, etc also have an effect.

[-Ralph-]

This is a fishtailing type incident which is as much luck as management to not book a short stay in the highside hotel (nice view but the food's sh*t).

Recovering is a case of not whacking the throttle shut when the back end steps out, as this guarantees a highside. You need to close the throttle a bit but not all the way to allow it to regain grip.


In the case of the OP yes, but not in Stig's case for instance where it was the front wheel landing badly that cause the slap. Which is why it can be so deceiving as people read these bits of advice and apply it to every situation where the bars slap, but there are different causes for bar slapping, and different remedies.

Personally I find that I can't think of remedies in these situations. I can only think of the colour of my pants. And you won't necessarily instantly realise what the cause was anyway if you weren't expecting it. So my reaction to it is, don't accelerate, don't steer, don't brake and don't slam the throttle shut, do nothing!. You decelerate anyway because it's instinct when your trousers are turning brown to loose speed, but so long as that deceleration is gradual, not snapping the throttle shut, that's not usually a bad thing.

[Jimmy2Feet]

as far as i understand it is still the gyro effect that is the cause, as i believe that the force of of the gyro from the wheels is so great compaired to all other forces placed on the bike that it will alway move in a straight line as long as the rest of the bike is upriget. hence why you can lean the bike into corners. (I THINK)

[MattCollins]

Ralph, I might dispute your version of a tank slapper. Any time the front end gets out of control with oscillations from side to side it is a tank slapper.


This is my take on it...
Hold a bicycle wheel by one end of the axle, give it a good spin. It'll run true, until it is is destabilised... give it a rap and try to hang on to it. The same forces are at work with a motorcycle tank slapper, with 10-20 times more rotating mass and a few to many times the rotational speed - the forces are huge. The difference is that the motorcycle wheel is only free to move on one axis, but it is damped on that axis by axle trail and a critical element in the damping is contact with the road surface. There is also be a degree of damping exerted by the rear wheel (with much greater mass) which is fixed in all axis relative to the front - it will resist changes in bike direction and lean. Without damping the front wheel would continue to wobble around until it stops.
So... power on, the front becomes light, the rear wriggles around, the front is disturbed by either the road surface or the movement from the rear and there is that rap on the bicycle wheel.

However... there are probably dozens of scenarios where it is possible to upset the front end.

As far as rider input goes, the best a rider can hope to do is help damp the little movements. The rider has no hope with the larger oscillations because the forces are so great, but unless the rider is aggravating the situation, the best course would be for the rider to hang on. Personally, I fit a free to centre steering damper to almost everything I ride to take care of the chore.


Stig, it is the destabilised gyroscopic effect of the front wheel that causes the tank slapper in the first place. As mentioned, damping via geometry and friction brings it back in line.


EDIT: Way too slow. :D

[-Ralph-]

Ralph, I might dispute your version of a tank slapper. Any time the front end gets out of control with oscillations from side to side it is a tank slapper.

That's fine with me mate, I'm not really bothered who calls a tankslapper what. We've done this debate a million times on the forum. I'm happy with my version of it and I'm quite happy for you to have yours.

The more important point I was trying to make is that lots of people use the term tankslapper in exactly the same way you do, for every bar wagging or slapping incident, but the discussion always seems to end up in how to avoid or deal with my version of a tankslapper "they say you need more throttle, etc, etc" :rolleyes:, which is not valid, not always even good advice and downright dangerous if some idiot decides to try and follow it.

[Stig]

no he meant OP (imo)
Oh. :)

[MattCollins]

Ralph, I might have been a bit clearer with this too.

Ralph, I might dispute your version of a tank slapper. Any time the front end gets out of control with oscillations from side to side it is a tank slapper.

"Out of control" meaning that the rider cannot do anything about it other than to back off and hold on...

[-Ralph-]

Ralph, I might have been a bit clearer with this too.

"Out of control" meaning that the rider cannot do anything about it other than to back off and hold on...

Gotcha! ;)

If it gets to the point where it's bouncing hard of the lock stops at a rate of knots, your probably coming off anyway.

[-Ralph-]

Luckily I never had one bad enough that it didn't sort itself out, but I have had one following a near highside, that had just about sorted itself out when I ran out of road! I was already out of the saddle in a position where my shoulders were over the bars, and the deceleration of the bike when it hit the muddy grass verge was enough to dramatically slow the bike, and I carried on going at the same speed. So down the road on my face, as the bike straightened out, ran across the grass verge on it's own, hit the hedge and toppled over with next to no damage. If I had been another metre or two further away from the grass verge, I'd have recovered it.

[Swer]

for my few :confused:

[QUOTE=hongman;2464845]I think its a much debated subject, some say give it some throttle, some say ease off a bit, some say keep it cracked on.

Try all in one case and the only thing that work for me was to push on again, fecking wrest were so weak after that one trying to hold it, see him too :reaper: had even thought about which side i was going to fall on to too, (away from the cars i was over taking ) was i happy when it was all over. another cheap lesson learned !