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R12RT instabilty solution -- steering damper?


paulcbrowne

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Other posts have discussed the wind turbulence sensitivity of the R12RT. The RT does not have a steering damper and I wonder if anyone has tried to apply a steering damper to the new RT.

 

I traded my LT and F650GS for my RT in August and find the wind turbulence very inelegant to say the least. Neither my LT or 650 exhibited anything like my RT. As another thread has suggested several solutions, I've tried tire pressure changes, different combinations of boxes on/off/loaded/unloaded, and shock adjustments (both stock and my Ohlins replacements) to little avail.

 

On another site I saw that several '06 LT owners had had their steering dampers replaced for instability symptoms that sounded similar to those of the RT.

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I dunno, I think my R1200RT is rock steady. I have ridden it in some very high winds crossing Canada.

 

Are you riding with a death grip on the bars?? I know some others have relaxed their grip on the bars and let the bike just move around. IMHO, the RT is much more stable in high winds and behind trucks than an LT.

 

Not sure a steering damper would solve anything. The steering damper is included on the K1200LT for reasons other than wind turbulence. All of the old style K bikes have steering dampers included not just the K1200LT.

 

Good luck

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I'm used to riding off road and on dirt -- therefore, I understand letting the bike have its way and not holding a "death grip." IMHO, the RT in turbulent air is worse than an LT on a gravel road by a long shot!

 

But, you may have offered a clue -- my LT was rock solid in wind and turbulence, but I had a low, European w/s. Any folks with shorter than stock windshields have an input?

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ShovelStrokeEd

I really doubt a steering damper would help the situation. In fact, it might just make things worse.

 

The problem, as described by most, seems to be a matter of aerodynamics not one of deflection at the forks or rider input to the forks. The fairing is already putting unwanted inputs into the chassis, hence the feeling of nervousness. I seriously doubt adding more input to the chassis would offer a solution and that is exactly what the steering damper does. Its real use is to trasfer fork deflections caused by off axis loads from the wheel to the chassis and keep them from the bars. They can be of some use in damping periodic oscillations of the front forks but quite often just transfer the oscillation into the chassis. Primary use is to reduce "head shake" on agressive corner exits, in particular over bumpy terrain. I have seen, and experienced, too tight a steering damper actually cause high speed instability.

 

I also doubt that the matter is really very serious so long as you don't spend all your time riding in the wake turbulance of large vehicles. Even there, the chassis can be bouncing and weaving around quite a bit before it will effect the tire contact with the road.

 

This is the price you pay for riding a bike with a great barn door of a windscreen on there. Small forces at the ends of the screen are leveraged into the chassis. I'll offer a case in point, my Honda Blackbird, no more windscreen or frontal area than the average sport bike and it is rock solid at ridiculous speeds as well as nearly immune to crosswinds. I do get a little wiggle in the wake of big trucks but it is barely noticable. I also manage to stay just about as dry at speed as anyone else in the rain. Once stopped, I get just as wet as well.

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I had the same problem....it took new shocks to fix it....I've always thought the R1200RT was little jittery on the highway ...with or without wind the front end just feels too light and unstable.

 

Good Luck

Whip

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I have a Cee Bailey's short screen and I can't say I notice a difference in stability; only more wind hitting my upper chest(and more wind noise).

 

My RT seems stable to me; a little less so if I'm riding without side cases. Do you ride with your windscreen up or down? I generally have my about 1/4 the way up.

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I can't say I'd characterize it as "unstable" but I do notice what I'll describe as squirming in turbulent situations (behind trucks, etc). I've been running Bridgestones since new but am planning on trying Continentals for the next set. It's always felt to me (perhaps erroneously) that it was a tire issue rather than something inherent in the bike. I'll have to wait for a tire change to know if that's the case.

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Paul, as several have stated, a steering damper is not likely to help. They are designed to dampen rapid movements, like the front being deflected when it hits a big rock on the trail or a big seam on a track. The movements they are intending soften are the induced by the contact patch itself--not the body of the bike.

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The 1200RT definitely has faster steering than the 1100/1150 which many feel has improved the handling, or low-speed handling at least. But the other side of the coin of quicker steering is less stability at speed. As with most such design considerations you pays your money and you takes your choice.

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It might be interesting to do a survey of "squirminess" vs. what tires folks have.

 

My bike came with Bridgestones. It didn't squirm though they didn't last long. It now has Contis. It still doesn't squirm. I suspect another problem than tires of the design of the motorcycle.

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I have to say that my new 07 rt seems more stable in winds than my 1150 unless I have the big top case on the bike.

Mine came with Michelin pilot road tires.

 

Bill

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I don't think it is a tyre issue. Fundamentally I think it is an aerodynamic effect but with a lot of other factors.

 

My experience is that some bikes are more prone to it than others. My own bike is sometimes more prone to it than at other times (whether on Michelins or Continentals).

 

Certainly the large top box ridden solo has a big effect. Other factors appear to include fuel load and tyre pressure. I wish I could pin it down.

 

A thought I had the other day is that it depends on how I am sitting. Not for the aerodynamic effect on me (screen position makes no difference) but because of weight distribution. I have an impression (not been able to try it out yet) that the further forward I lean the better it is i.e. the weight distribution may be too rearward biased. Anybody know what the split is?

 

The GS (the early ones anyway) tended to be set up a bit nose high which made them feel twitchy. Banging up on the preload, lowered the front and transformed the feel and handling. I'm wondering if there is a rather similar effect here.

 

Paul

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Out of the 3 BMW's I've owned the KGT was the rock, next the 1200RT and then the 1150RT, but none of them could be called twitchy or unsteady in wake turbulence.

 

Try a different RT under the same conditions and see if you observe the same kind of instability. This will help you narrow it down to either your bike or the RT line in general. If it is your bike look for the obvious differences--tires, pressures, suspension set-up, wind screen, and so on.

 

The 12RT is an incredibly stable bike at speed in clean air. I can take my hands off the bars and it will track straight down the road--no problem.

 

grin.gifgrin.gifgrin.gif

medium.jpg

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Just to clarify my earlier post, when I said it varied between different bikes, they were all 1200RTs. And I agree it is very stable in clean air.

 

I have even ridden a bike identical to mine (tyres, pressures, accessories, even the colour smile.gif) and it was noticeably less affected by turbulent air than mine.

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Just to clarify my earlier post, when I said it varied between different bikes, they were all 1200RTs. And I agree it is very stable in clean air.

 

I have even ridden a bike identical to mine (tyres, pressures, accessories, even the colour smile.gif) and it was noticeably less affected by turbulent air than mine.

 

Any difference in what you had for lunch on both days ?? grin.gifgrin.gifgrin.gif

 

The top box thing is something I agree with , having ridden with it on [ solo ] .

The hands free idea is something I'd rather not try [ having already done a variation of it as a result of a pheasant ...or two ...!! ]

 

Steve

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I am more than happy with the handling of my R1200RT. I also believe the threads that relate the "death grip" on the bars to twitchiness. The more relaxed I am on the bike, the better it works for me. I have Conti Road Attacks, and will stick with them. I wouldn't give you a plug nickel for the Dunlops that came on the bike. Well, that's a little harsh. They stuck well enough, just wore out fast and sang like a bird. The Contis, no singing at 8,000 miles. Good tire.

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I'll throw in with the rest of the crew. I think most of the instability is rider input. The RT is way more maneuverable that a bike of its size should be and tiny rider inputs will make the bike move around. Try just hovering your hands over/around the grips on a straight stretch of road.

 

Of course my last bike was a cruiser with a fork mounted windshield, talk about wind influence on that thing. grin.gif

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Try just hovering your hands over/around the grips on a straight stretch of road.

 

Done that - still the same effects as reported above. I thought it was just down to rider input as well though I tend to ride with a very light grip anyway. So I made sure I really concentrated on what I was doing in that area both on my own bike and when comparing with other ones (loaners from the garage). So I don't think its rider input - certainly not solely that.

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Based on all of the comments, I did a little experimenting. The "instability" seems to be mostly a factor of some largish sail area relative to the RT's lightish weight (and maybe quick steering). I concluded that this is not a problem, just something I need to learn to deal with. Depending on your riding conditions, I can see why people can have very different imprerssions.

 

I did a test this morning in traffic. A good deal of squirminess happened. I was deliberate in selecting vehicles to follow. The "instability" is turbulence off of vehicles that create a "dirty air" wake. Depending on the vehicle, there may be almost no wake or it may extend a couple hundred feet behind a squarish box truck or van.

 

I also tried a run in strong wind yesterday. I ran with the wind head-on and off the port beam. The wind is not nearly as bad as the turbulence in traffic. In fact, the bike seems quite stable in strong winds except when stopped.

 

Having the windshield all the way down mitigates some of the effects. Loosely holding the bars seems to really help -- of course that's a little harder when you're on the lookout to avoid deer in this their mating season when they act really crazy.

 

I will be working on Limecreeks' alternate riding position!

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Instability? There is no instability with an R12RT.

There is some buffeting while behind other vehicles but this is easily fixed - drop back from the vehicle or pass the bugger. I am sure all motorcycles will be the same in this situation.

The effect of crosswinds or oncoming trucks on the R12RT is no different to the R11RT and thr R100RT and I am sure other as well.

I think a steering damper would be unnessary and cause more problems then it would solve.

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I have found some instability with my '05 RT. I still don't feel comfortable riding in the rain (when necessary) due to this, although I can deal with it on dry highways. It does feel like the front is light. The tires are good and hold very well in corners and during braking.

 

I believe part of it is my riding position and part bike. I am 6'2" but more upper body so I sit high in the saddle. I have the regular seat in low position. The low seat didn't work for my knees (and belly! :-) ) I tried the CeeBaily +2H +3W but that didn't help.

 

I found myself more stiff armed most of the time. So I recently added the Moto-Techniques bar backs, which helped loosen my arms. I also switched to the Aeroflow Tall windshield and that helped a lot with the stability. It has a lower profile than the other windshields. The only complaint about the Aeroflow is the constant flexing (annoying at times) and it has increased the noise factor and buffetting for me.

 

Another note, the stock demo bike was a lot more stable when I did the test ride then my bike (stock). Except for the tires, they are identical, including the large trunk. Mine has Z6 and the demo has Pilot Roads. I will switch to the Pilot's next change. I've had my bike checked over at the dealer a few times and they say everything is normal. Of course the mechanics are lighter and shorter than me so it's not the same conditions.

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I have found some instability with my '05 RT. I still don't feel comfortable riding in the rain (when necessary) due to this, although I can deal with it on dry highways. It does feel like the front is light. The tires are good and hold very well in corners and during braking.

 

I believe part of it is my riding position and part bike. I am 6'2" but more upper body so I sit high in the saddle. I have the regular seat in low position. The low seat didn't work for my knees (and belly! :-) ) I tried the CeeBaily +2H +3W but that didn't help.

 

I found myself more stiff armed most of the time. So I recently added the Moto-Techniques bar backs, which helped loosen my arms. I also switched to the Aeroflow Tall windshield and that helped a lot with the stability. It has a lower profile than the other windshields. The only complaint about the Aeroflow is the constant flexing (annoying at times) and it has increased the noise factor and buffetting for me.

 

Another note, the stock demo bike was a lot more stable when I did the test ride then my bike (stock). Except for the tires, they are identical, including the large trunk. Mine has Z6 and the demo has Pilot Roads. I will switch to the Pilot's next change. I've had my bike checked over at the dealer a few times and they say everything is normal. Of course the mechanics are lighter and shorter than me so it's not the same conditions.

I found the same 'nervousness' on the RT. Demo05 was solid, my new06RT moved so much in the first 500km behind a cube van I thought I had a flat. Now with 10,000km on the pilot roads it's OK and I've got used to it. No top box, bags on or off no difference.

 

Just back from Baja (tank bag only, 160lb rider, no bags or top box, tyre pressure 34/39psi) where I purposefully set the cruise and followed a semi for quite a few miles at 120kmh playing with ESA settings, stock screen position, where I sit, no-hands too (for those who say grip lightly) all with no improvement.

 

Conclusion from some other threads here is some bikes are nervour and some aren't. Go figure.

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Just got back from 1600 miles on my '06 RT with Z6's on them... The 1200RT was no "squirmier" my 1150RT or any other bike when in the wake of a large truck. I don't think there is any reasonable expectation of a bike being stable in that turbulent environment. The best advice was given earlier... back off or pass the bugger! This is normal behavior I have experienced from every bike I've ridding the last 25 years... with cases/without cases, with fairings/without fairings - it don't mattah!

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Just got back from 1600 miles on my '06 RT with Z6's on them... The 1200RT was no "squirmier" my 1150RT or any other bike when in the wake of a large truck. I don't think there is any reasonable expectation of a bike being stable in that turbulent environment. The best advice was given earlier... back off or pass the bugger! This is normal behavior I have experienced from every bike I've ridding the last 25 years... with cases/without cases, with fairings/without fairings - it don't mattah!

99R11S was rock solid (best bike ever)- in any turbulent vehicle or windy environment, with or without bags up to indicated 225kmh over 7 years of riding.

2005 dealer demo R1200RT was pretty solid

2006 R1200RT was initially more nervous than any bike I've ridden over 36 years - now with worn tyres it's OK. Will see what happens when new tyres go on soon.

Yup - I never follow a semi, but it was fun to play and experiment there for a while with no other traffic on the Baja road for miles smile.gif

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I guess I'm lucky as my 2006 R1200RT is very stable at highway speeds and is equal in this regard to the 1500 GoldWing I previously rode. The BMW almost always has the 49L trunk mounted and bags on/off makes no difference. Tires are OEM Bridgestone BattleAx 020 inflated to either 35/39 or 40/42 (again - makes no difference).

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I had a problem with my 1200GS doing that, especially in crosswinds, so I traded it for a 1200RT and haven't looked back. I'm 6'7" and have no problems. I have the tall seat with suburban machine lowering pegs and I set the windscreen at about half height. I ride in all kinds of weather and the bike is solid as a freight train. I do however, run 38/42 f/r air pressure and have the rear preload cranked up about 3/4 of the way and have the shocks set pretty firm cuz I go about 285. No ESA for me. The pilot roads have over 8k miles and will be replaced this winter so next spring I'll have fresh rubber, but they would probably go 10k easy. Seems to me that you may have a shock problem, but trying to get BMW to do anything about it, well......You could always give half a years pay and your right arm for a set of Ohlins!

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The RT does not have a steering damper and I wonder if anyone has tried to apply a steering damper to the new RT.

 

Last weekend, I was surprised to see hydraulic steering damper on the '07 R1200R; I'd assumed dampers were obsolete (you're correct in surmising my lack of interest in sport bikes). If you have your heart set on installing a damper, well, I'd look closely at the R12R's unit to see if it can be installed on an RT.

 

Wooster

 

BTW, does the R12RT have "glove box" in fairing ?

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I believe part of it is my riding position and part bike. I am 6'2" but more upper body so I sit high in the saddle.

 

I really think that a lot of it could be solved by adjusting riding position, although there may be several causes which in the right conditions come together to make the bike a little light in the loafers.

 

I am only 5'8" and for me, the '05 RT is solid. And, I can and do push it around because, well, it's just FUN. I notice little turbulence behind trucks or in breezy canyons on Hwy 1, but not enough to move the bike off its track. I also notice turbulence with just the large top case on, which makes perfect sense -- and I just raise the windscreen a little. The lightness in the front end for me is solved when I adjust the suspension, my riding position, or take the top case off and ride with less weight on the back tire.

 

The biggest difference I feel is when I adjust my riding position a little further forward. I have long arms for being such a little monkey, so I tend to sit further back on the seat. When I scoot up a little, the problem is solved and, incidentally, I can scratch on the twisties with the crotch rockets and still be more comfortable and relaxed. Kind of a weird way to mitigate what could be a design flaw, but it works for me...and let's me know when my posture sucks as well.

 

Not sure, but my suspicion is that BMW actually made a great bike for us little people and the big people finally got what they deserve... lmao.gif

 

I'm new to this bike and to BMW, but after about a year with this bike I will probably never ride another in this class...too many reasons to mention.

 

Glad I crossed over -- and glad I found this forum.

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Since I started this thread, I thought that I should pass along the one thing that seems to fix the problem -- tire pressures. I bumped mine up to 36F/42R to carry my wife and forgot to lower the pressure afterwards. Surprise! Much less squirminess in traffic air turbulence where vehicles are causing quite a bit of turbulent air. The ride's a tad harsher, but that stability is well worth it since I ride in traffic often. (BTW, I had tried raising/lowering the seat, changing my posture, even installed Ohlins. Ohlins weren't for the instability, but for much improved ride and handling.)

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