| Author | Message | ||
     Nm5150 |
Yesterday I had the worst tank slapper of my life at around 95mph or so.I really thought I bought the farm.I would like any thoughts on who makes the best steering damper because I think it will be money well spent. | ||
| Jng1226 |
Can you describe what caused your tank slapper? I've got Ohlins steering dampers on some of my other bikes, but I have yet to put one on the 1125R. The front gets light and starts to wag slightly when the powerband hits at around 8K rpm and up in lower gears. Riding my XB9 with its 2-inch shorter(!) wheelbase with same 21-degree rake will teach you to be light on the handlebars and only give steering inputs with your hands while using your feet, legs and core to hold onto and move around on the bike. I like the Scotts rotary damper because you can adjust the damper range sweep and damping independently, but they don't seem to make it for our bikes. Jeff Edited for typos. (Message edited by jng1226 on January 02, 2010) | ||
| Xtreme6669 |
Do you ride an R or a CR...? No options out yet for the CR but there are a few for the R... GPR seems to be the most popular I have seen used on the Buell forums. | ||
| Milt |
Please help educate an ignoramus (me): What's a tank slapper ? | ||
| Bsdfool |
Take a look - http://www.youtube.com/watch?v=LZ1srcQMa_0 | ||
| Xnoahx |
That vid shows it pretty good, front end banging from lock to lock at high speed. | ||
| Blur |
I love Scotts dampers. GPR's are a little bigger but work off the same concept. Ohlins are also good and they are piston instead of the rotary. I've seen GPR's and Ohlins available for the R. Nothing yet for the CR. | ||
| Littlebutquick |
i had a really bad tank slapper just drag racing .got my self a ohlins one its never done it again  very pleased with it but hard to set up no instructions | ||
| Milt |
What causes a tank slapper? Is it operator error? Harmonic oscillation at some specific speed in reaction to a specific input? Can you feel it coming? How do you control it? | ||
| Nm5150 |
I was on one of my favorite back roads.A lot of curves and two quarter mile straights.I came out of a tight(30mph)left hander on to a straight with a very heavy right hand.I grabbed second and right after I grabbed third I hit some small bumps and the front end went WHAKIDY!I just hammered on the gas and hung on and it straitened out but not before I crapped my pants  | ||
| Ohbuellman |
Likewise, I had lot of instability up front at high speed, so decided to look into a steering damper for the R. Check the search function as there are quite a few threads on both the GPR and the Ohlins. While I was initially leaning towards the GPR, I discovered that it can not be used with the Buell tank bag. Since most of my riding is on the street with only occasional track time, I opted for the Ohlins, which I have been quite happy with. It does the job, is out of the way, but difficult to install as noted. | ||
| Americanmadexb |
I have seen that video a hundred times, and all hundred times i laughed. Is that bad?  | ||
| R2s |
That's not a tank slapper. That's some gnarly head shake though. This topic comes up every now and again. All high horse power bikes will get the front end light and its up to the rider not to over compensate before it gets weight on the front tire and you turned the bar too much because it wasn't' doing anything anymore. That can cause a bit of a head shake at speed. but it will correct its self. Also a steering damper will not stop a highside from the rear end stepping out coming out of a corner. The 1125R is a very stable bike in stock trim and does not need a steering damper. If your gonna be racing it and messing with the steering geometry for maximum flickability you will be needing one. and if it makes you sleep better at night go ahead. Go fast goodies wont make you faster ether, proper technic will. If you do, don't put on a GPR style. they mess up the looks of an otherwise clean area. | ||
| Wera44 |
Bitubo from www.traxxion.com is another option. (Message edited by wera44 on January 02, 2010) | ||
| Jdugger |
I'd have to agree for street applications, the damper isn't really necessary. It will cover up a lot of bad habits and slow the steering of the bike. I find that I need one on the track, and the reason is I just can't keep unnecessary input out of the bars at WOT, and the unsettled nature of the front tire skipping along, wobbling the front, etc., takes some confidence away. When the headshakes like mad under hard throttle, it's absolutely, purely, 100% RIDER ERROR, and I openly admit I suffer from this tremendously. The other major thing a stabilizer/damper will do for you is if you do get into a legitimate tank slapper it will help stop the oscillation just enough to recover the bike. I find it comforting the way the ohlins one sorts out the steering when going into a corner while hard on the brakes. As the rear wheel is coming off the ground under braking, the damper does help sort a bit of the wagging out. Other solutions for sorting out tank slappers include pressing hard on just one side of the bars, or adding a fair bit of gas to get weight off the front tire, but that can be a bit hard to remember/execute in the heat of the moment. | ||
| Jng1226 |
Thanks Wera44 - Bitubo is very nice and appears to be the same price as GPR and Ohlins. Do you have any experience with these on the 1125R? At Jennings GP (North Florida) I was consistently getting a slight shake while trail braking from an indicated 145 mph down to about 105 for turn 3. This was a bit unnerving and no matter how smooth I was on the controls it would still shimmy. I was waiting for EBRs prices on the Buell/Ohlins setup but for close to the same money I'd rather go with the gas-charged Bitubo. Jeff | ||
| Bigblock |
The GPR works very well, and if you get creative, it will work with the tankbag. I added a strap attached to my radiator mount for the right side of my tankbag. Headshake and tankslappers are NOT always operator error, and why not have the insurance of a damper? To insist that they are useless or an excuse for operator error, is just childish. And hell, if they can compensate for operator error, who the heck is perfect anyways? Surely not I! Anything that might help keep you alive in that jungle we call motorcycling, is a GOOD thing. | ||
| Redscuell |
Did have the GPR, took it off for a rebuild by GPR, put it back on -- and took it off forever, the damped effect was now so terrible. Once loved it, now hate it. And have never had head shake, on or off the track, with or without the damper, in 25,000 km. So I don't personally see any need for a damper (though I admit, at first I was a big advocate of the damper). | ||
| Westmoorenerd |
I had a pretty scary tankslapper on my CR...WOT 2nd gear on a backroad against a GSXR-1000. Put my weight (all of 160lbs) forward to keep the front down, next thing I know when I shift to 3rd, tank slap. Scared the shit out of me afterwards, not really so much when it was happening, guess instinct just kicked in. So I'm all for trying to get a dampener, too bad there's no easy install on a CR. | ||
| Jdugger |
West, Your actions are exactly why you got into the tank slapper. If you are "holding a front end down" and putting any kind of input into the handlebars as the front is skipping along, each time the bike touches it will try and correct itself. A sudden disruption to the chassis -- such as the weight transfer to the front tire of a shifting action -- got the front loaded up and started the shake cycle. Trailing the throttle a bit or even touching the rear brake (to modulate the power) are probably better solutions to hold the front down. *chopping the throttle* and putting more weight on the front end will make the condition worse unless you have corrected the inputs that caused the issue to begin with. Also, don't forget to pump your brakes after a tank slapper. Generally, if you have been a real tank slapper, the pistons are shaken apart, and it will take a couple of lever pumps to get the brakes back. Big, I don't think anyone suggested they are useless. I suggested that headshake at WOT is rider error, and it's caused by incorrect rider input misaligning the front wheel as it's skipping along. Dampers are not without costs. They slow down the steering, for sure. They also tend to promote bad rider habits ultimately more dangerous. Good ones are $500 or so, so that's a consideration, too. $500 buys a lot of nice parts or even a great set of tires, some gas and oil! Hey, each to their own, but a damper is not a panacea, and it's not necessarily the right answer for someone getting headshake under WOT and wheelie conditions. | ||
| Wera44 |
Jng1226: I just ordered it a few weeks ago when I ordered other stuff from Traxxion. I havent had it on the track yet so I have no input but Im sure its top shelf. I also know that it can be serviced by Traxxion or the end user but I dont think the Ohlins can. If you truly get into a tank slapper if you put pressure on one side of the bar like suggested above it will snap your wrist in two. The only thing you can do is not put any input into the bars, let the bike do its thing and hope it doesnt throw you down. If you ride aggressively or on the track get one. (Message edited by wera44 on January 03, 2010) | ||
| Duggram |
From page 44 of "Techniques of Motor Cycle Road Racing" by Kenny Roberts, the best road racing manual of all time. "The steering damper helped stop the bike from wobbling, but it didn't slow the rate at which I could flick the bike into the corner. The steering damper will stop the bike from going into a terminal shake, but there is no way you can turn the bike that fast at high speed so the damper will never slow you down. It would while you rode round the paddock at walking pace, but not at high speed on the race track because it is a hydraulic damper...." BTW I use a GPR. (Message edited by duggram on January 03, 2010) | ||
| Duggram |
Also, the rider that died at the Fontana WERA race last January would most likely would have lived if he'd had a damper. | ||
| Jng1226 |
Wera44 - Thanks for the info on the Bitubo damper. Can you please post a review once you get time on it? Thanks in advance. One more note about tankslappers or steering instability on an 1125. I ride fairly aggressively on the street, but no where near the pace at the track, that is a completely different set of conditions. I have never had a hint of instability from my box-stock 1125R on the street, but it does feel twitchy at the Jennings GP track. Road/Track layout and characteristics combined with rider technique definitely have an influence on whether you experience steering instability that can turn into a tankslapper. Jeff | ||
| Jdugger |
Steering dampers don't slow the steering on the track much, true. You notice it on the street, in particular at slow speeds when using a lot of steering travel like parking lot maneuvers and riding around the neighborhood. My track bike has one. My street bikes don't. | ||
| Moosestang |
I've been reading about head shake and tank slappers. It seems that suspension setup can contribute to head shake, so I'm adjusting the rear first to see if I can eliminate the head shake I get at WOT. I'd love to blame rider error, but I'm going in a straight line for christ's sake. | ||
| Duggram |
Before I got my damper the only time I got head shake was over a bump, whether coming out of a turn or on a straight. If you think about it the two ways you contribute to the problem are weight forward and pressure on the bars. You can do this in a straight line. My bike only sees track time now. I concentrate on light grips and weight neutral on the pegs. Not sure if this is the answer, but I can honestly say it's been a more than a year since I felt any head shake. | ||
| Justa4banger |
SO how important is suspension setup to prevent a tank slapper? I set up my bike by the manual for my given weight and then i just a soften them like a 1/4 turn. Yesterday was my first opportunity to do a high speed pass and i basically maxed the tach in 6th. Now given that i have been educating myself a bunch on how to properly ride and also prevent tank slappers, i felt the bike is actually pretty stable at max velocity. I tried to keep my hands neutral, hug the bike with my legs and not tugg on the bars.. I think i would still feel better with a dampner, but i don't think i need one. I guess my question is for those that have had head shake.. have you setup your suspension.?? and if so..HOW? | ||
| Duggram |
4banger, that's a damper, not a dampener. But that's semantics.... In the fall of '08 I took my bike of the street and only use it on the track now. I put 1.1 kg springs in the forks and had an expert help setup the suspension during my racing school that fall. The bike handles fine, but I do plan on AK-20's and a TTX shock this summer. Even after this setup I could still get some shake when hitting seams in the track or transitions. With a GPR and riding style changes I don't have to think about it any more. I don't mind using a damper. Some may think this is unnecessary or un-macho, but does it really matter what they think. If a damper was good enough for King Kenny, it's good enough for me. | ||
| Nm5150 |
First off you definately loose your front brake for three or four pumps.I almost remembered that too late My bike is set up as per the owners manual for 170lbs.I weigh 165 and have a set of bags.It did happen going straight,WFO over some small bumps in the road right after I hit 3rd gear. |
