Archive of BMW Motorrad Club Cape (2006 - 2019)

I have one on my R1200GS.....I sometimes still fall!!!:-) I found the front a bit light on my previous bike AT THAT TIME, and had a tank slap once on tar on a demo bike going into wind(worn knobblies on the bike at the time) Now since then some training and a fair amount of riding I now know I was too tense on the handle bars causing the problems. I am not sure if I would buy one now. As most of my riding has been with one so no clear reference point to advise you yay or nay. You are welcome to call me if you wish.0827723527

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I'm also not so sure that a steering damper will help in soft sand... Tank slaps yes! For that money you can rather do the CountryTrax intermediate/advance which will probably be of more value in the long run... I could be wrong ;-) Corné Kloppers http://www.bikepics.com/members/pantsula/07f650gs/ 0849130391 ckloppers@gmail.com

Corné I tend to agree, at the time I was not as loose on the bars,and nothing like training and practice, BUT the steering dampers have a place on some bikes and in some situations...on the GS I am no longer sure of the need.

I agree with Corne. Problems with tank-slapping are the result of bad tyres, incorrect pressures, bad suspension settings and some environmental factors like wind and road surface. On sand, my guess is rider skill is more important than a steering damper. I can't say I have noticed the BMW instructors using a damper. I would do the Country Trax intermediate weekend, and spend any extra money on new tyres. On the weekend you will learn to set suspension properly, correct tyre pressures, and riding techniques for sand and other terrain. Website Administrator [http://honeybadger.net Honey Badger IT Services]

AND SPEED! :-) I had two tank slappers with my 650 on gravel roads doing 110/120Km/h + I now keep in the 2 digit speed going off road and I'm HAPPY ;-) Corné Kloppers http://www.bikepics.com/members/pantsula/07f650gs/ 0849130391 ckloppers@gmail.com

I agree Corne. On the last West Coast trip I took a wrong turn off, I had to cath up and found myself in a spot of bother a couple of times, I soon realised that 140 - 160km/h on a R1200 ADV off road is not the idea of fun....I now prefer 80 - 100km/h. Rather safe than sorry. Johan de Jager "It's all about the ride, nothing else"

Hey Corné print out and frame this thread/post....it's NOT often you get people agreeing with you!:-):-)

And I am willing to to be the stupid one here -can somebody please explain the term "tank slapper" since I only read about it on these forums, did not experience something like that or if I did, did not know that it was a tank slapper!!!!

i don't normally say too much but here Charles is spot on, the gs range to the normal guy/gal is not made for heavy off road work as many would like to believe. they are capable machines but not designed to be high speed off road conquer everything speed demons, this is the department of specific off-road enduro bikes. having raced in my younger days it never ceases to amaze me how people think that the word gs means it can do anything off-road. skill is an acquired thing and cannot be bought with money or a fancy bike, it has to be nurtured and takes years to achieve. hope this doesn't pee too many people off but it's fact bought with experience. cheers mark i only work to support my hobbies!!

Hi Johan a tank slapper...'the end of the handle bars slap the side of the tank'. If you had had one, you would NOT have forgotten... easily.It is when the front wheel(handle bars) swings rapidly from side to side while you are riding forwards (and your body's rear puckers equally rapidly).

The gents have covered this well, the only time I had the T-S was early on, on tar going up a rise then at the top a cross wind and worn knobblies, and I was tighter on the bars ...I thought I was a gonner. I now am sure the cross wind hitting my shoulders, with a tight grip and still accelerating, set it off. I no longer find gusty cross-winds a problem.

Thanks Then maybe I had a smallish one on my trip to Eendekuil! My next question would be how to avoid one? Sorry, missed your latest insert - Your description (on tar) differs then from when one goes through uneven sand?

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 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. Reference: http://en.wikipedia.org/wiki/Bicycle_and_motorcycle_dynamics Corné Kloppers http://www.bikepics.com/members/pantsula/07f650gs/ 0849130391 ckloppers@gmail.com

Thanks - now my brains must get some practice to keep up with split decisions when unexpected tank slappers occur!

I had a tank slap with Neil on our Middelpos trip. Very frightening. The handlebars whack from full lock one side to full lock the other side. Mine was caused by corrugated gravel road and I was lucky that I managed to stay upright. I was going too fast for the road conditions. Corne ... in support of Neil's posting, have you bought an 1150 or 1200? Just wondering why everyone is so agreeable with you today? ''The world needs dreamers that DO!''

Hi JohanM For what it is worth, I have as yet not experienced a tank slapper on a BMW, and I have been riding these things since 1979. maybe luck, stupidity or a fantastic Gaurdian angel. On other machines YES, remedy, open the throttle and lean back, if possible until the slap dissapears, worked for me. Not easy the first time to excercise this, but once you have experienced the remedy it's easy. Ignore opinions, heed facts. Feet on the pegs, always.

I take notice! Before this new knowledge I was wondering whether it was one's knees that slaps the tank...or maybe some other parts of the anatomy! Now I understand that it is the handlebars - and much more serious...

Charles the movement on my handlebars was so violent there was little chance for me to lean back let alone work the throttle and it happened really fast - it was all I could do to hold on to the grips; seconds later it was over as the bike slowed down. I'd love to know how other people handled similar situations, it would be useful experience to learn from. ''The world needs dreamers that DO!''

The bike I had it on, Marius had warned me about this and said to push forwards on the bars(I took it to mean ..push equally L+R simultaneously)I don't know what I did, but I suspect I did, as I had done a few practices based on his advice earlier in the ride. I would like to hear from gents like Maxl,Geoff,Leon and Freak on this one.

When it happened to me I had enough time to pray (screamed out a blasphemy into my helmet), to soil my underwear, and to throttle down. I suppose the best response would be to pull in the clutch and coast to a lower speed. Pushing or pulling on the handlebars changes the feedback frequency and will stop the oscillation also. Then I rode on at a lower speed and much more cautiously... The chief cause was worn knobbly in front and poor condition of the N7.

Oh, BTW I don't think it is possible to get a tank-slapper in sand. The road surface is too soft to support oscillation. What you get in sand is that the front wheel is like a supermarket trolley wheel stuck the wrong way - it will be pushed to the left or the right and lock there (and you will go down at low speed). A steering damper does not work under those conditions. What works it your leaning back, pulling back hard on the steering, and accelerating to more than 45km/h (i.e. sand-riding techniques). HTH

I have experienced many a tank slapper on the track when I used to race, the cause generally is when accelerating and the front gets light (off-loading the suspension) and the front wheel clips an uneven surface on the road and off you go… On road riding I can’t believe that trying to force the bars to stop “slapping” is going to work, you need to stabilize the back, the front will want to sort itself out naturally, so off the throttle and onto the back brake, worked for me. Remember after a slapper you have no brakes (excludes servo assisted brakes) Slappers can also be caused by faulty or badly setup rear suspension, most often problems “in the front” are usually caused from the back. And lastly, rider input, too tense, holding on to tight etc. can all contribute to the bike wanting to throw you off. General, ride in your comfort zone, don’t get sucked in, relax, look-up, slow-in fast out approach to corners. 2006 R1200S 2005 R1100S BCR 2005 F650GS(Cindy) Motorcycle Rider Training http://www.twowheels.co.za

Thanks Max, useful input. In retrospect it was definitely the slowing down (I think I did tap the back brake) that resulted in stability in my case. ''The world needs dreamers that DO!''