At what speed does the 12RT become unstable?

[chromenomad]

Another newbie question, sorry..

 

Took the new-to-me ('09) steed for my first extended highway jaunts today. After reading many reviews over the years of the amazing high speed stability, I was anxious to experience it..

 

.. but I did not.

 

I'm curious at what speed people feel like the RT becomes unstable? I assume it's supposed to be well over 75-80, yeah? (these tales of people running for hours 95mph+ seem to indicate that)

 

At about 77mph, the thing becomes vague/light/unstable to the point where it feels dangerous. I assume this is not supposed to happen. I was riding alone with luggage & topcase, had the ESA set to rider+gear, new metzeler tires @ 33/37. The sensation basically felt like.. well, like something was creating lift and that I wasn't actually planted on the road anymore. (That's not what was happening, obviously, but that was the sensation) Dropping down below 75mph, things felt fine again.

 

Not normal, right?

 

[motorbob]

Your tire pressures are too low. Try the recommended pressure for loaded bike: 37/43.

The RT is not unstable up to speeds highly illegal here in North America.

Robert

2008 RT

[Lmar]

I run pressures of 38-40 in the front and 42 in the rear. I have never noticed my RT to be unstable.

[Firefight911]

I was anxious to experience it..

 

.. but I did not.

 

Anxious - this could have caused you to tighten on the bike, in particular the bars, which would manifest itself as you indicate. The faster you go, the more loose you need to be.

 

tires @ 33/37.

 

As has been stated, this is just too low for tire pressure. Run 38-40 front and 42 rear. That will greatly improve the feeling you are getting.

[bobbybob]

Set your ESA to SPORT. You need the firmest setting for high speeds. When the OEM shocks on my RT were getting mushy (8K miles!) I felt that same sensation, sorta like you're not connecetd to the road. Flying a couple inches off the ground. Very disconcerting.

 

If yours still feels like that on SPORT---you need new shocks!

[chromenomad]

Ah, was running at solo non-luggage tire pressure. Will air up tomorrow and give it another shot. (and on sport instead of normal)

 

Bike has 11k on the clock, didn't expect the shocks to go that early.. if so, yikes!

 

thanks all,

-d

 

 

[Twisties]

Agree with the others.

 

My bike has been at top speed and it gets more stable with speed, not less so.

 

 

My old cruiser got unstable around 90 mph or so, so I know what you mean. This should not be happening with an RT.

[Thylacine]

I've topped out my '09 RT several times in the mid 130s and never noticed any instability. A couple of months ago I ran it for about 50 miles at about 110 on a remote road in the west Utah desert with no problems.

 

I'm not recommending going that fast; it might be labeled as a bit risky and illegal, but instability from the bike? No.

[plext]

I'm going with tyre pressure.

 

Don't forget that these things originate in Germany and are typically designed to do long high speed runs.

 

On a run between Munich and Hamburg I had one lingering on an indicated 225-230km/h for a long period and it was solid as a rock, only unstable thing was the fuel gauge which was dropping like a lead balloon. It in fact felt good for much more if only the poor old boxer could have come to the party.

 

No way those things when set up correctly can out run the chassis in my view.

[ollka]

Keep your windscreen low. When up, it causes turbulence which is shaking you, not the bike, causing unstability and "distant" feeling on the bike. Droppping the topcase or adding a pillion between TC and you makes it better. It should run like train doing 110 and above

[RodB]

Riding at double the posted speed limit gets the LEO's attention, which makes a checking account unstable.

The bike is OK at any speed it can reach.

[Motodan]

Stability, in large part, is dependent on who the rider is and their level of skill.

[CoarsegoldKid]

Stopped. Stands not deployed. Or when the tires are improperly inflated as already mentioned, steering head bearings loose, other things not up to spec. Aside from all that it's a very stable motorcycle in my opinion.

[hopz]

The real problem is very likely with the nut behind the handlebars.

 

When you near the ton, you may be, unconsciously, breaking into a large grin. If your headgear does not entirely block the wind flow you may be inducing a burble.... thus the problem.

 

Inflate your tires adjust your shocks... go ride.

[Mister Tee]

I've had mine up to 120. It was rock solid the whole way.

[Dave39]

I'm no speedster for sure, but I've taken my 09 up to 110 a couple times just to see what it was like, ESA set at single comfort and tires at BMW recommended pressures. The bike felt like it was on rails. Love it.

[racer7]

I noticed some wind wobbles on my 08 when new- casue was setting on stock shock- find the adjuster and add a little damping- its set for 175 lb rider stock.

 

I find with that corrected and correct tire pressures, the ESA setting makes no difference to stability though its impact on ride quality and basic handling as loads change is pretty obvious.

 

Also, newer riders or folks with new bikes sometimes tense up on the bars when the bike encounters wind buffeting. This can induce a feeling of instability because it interferes with the bikes normal gyro straightening properties. The solution is simply to ride with a relaxed grip.

[Dave_zoom_zoom]

Another newbie question, sorry..

 

I was riding alone with luggage & topcase,

 

I'm not to keen on using a topcase near top speeds. Even worse with it loaded. It seems BMW may have stated a max. speed with topcase somewhere.

 

If you really feel the need to run wide open (I do sometimes) I would suggest you take all the fore mentioned advise on tires, suspention and windshield. Loose the topcase. I haven't found the side bags to create instability, but they do slow you down just a bit. Yes, do stay loose. Flap your elbows. Helps to maintain a relaxed grip.

 

Be very sure you put no other lives in danger other than your own. I think it is best to work up to these things in steps, not in one big gulp. It's smart of you to ask qeustions. Maybe after you get all the answers, your quest may not seem as important as you first thought. When things go wrong at top speed, it can be VERY BIG. If you are not comfortable, don't do it.

 

Happy Trails!

 

Dave

 

 

[I812]

For myself it would be in a sharp corner going over the invisible gravel. Front tire breaks loose check. Rear tire breaks loose, check. Wobble and presto, back to normal. Nut behind the bars are known to come loose.

[tallman]

Not an RT, but wearing extra large touring lids, and GIVI topcase, and large rider, at speeds north of those mentioned, I've heard about BMW's doing that and they weren't unstable. (I mean I heard they weren't unstable. )

[moshe_levy]

I found my 2004 RT to be more stable in straight lines at very high speeds vs. my 2009, possibly due to the newer model's substantially lighter weight. The new model has plenty of leg left where the old model pooped out, though. It also has the huge 49L topcase which probably acts like a sail.

 

-MKL

[chromenomad]

I aired up this afternoon to 36/42 as recommended here. This helped a bit -- the sensation of liftoff was greatly reduced, but the bike really didn't feel happy or planted. There was also a hefty amount of vibration being transferred through (the whole bike, not just the bars) too. Worsened the faster I went.

 

I rarely have any need to go over 80mph, but I wanted to make sure everything is copacetic with the bike. You never know on a pre-owned..

 

Bike is heading back to the dealer for some other things tomorrow anyway, so I will have them evaluate and report back.

 

thanks!

 

-d

 

[notacop]

I'd suggest you use your seat of the pants intuition and never operate it at a speed greater than when you feel like your going to soil yourself.

For myself, that is over 85. Keeps me completely happy. I don't really care what my bike can theoretically do, or how fast others travel. Ride your own ride.

[markgoodrich]

I aired up this afternoon to 36/42 as recommended here. This helped a bit -- the sensation of liftoff was greatly reduced, but the bike really didn't feel happy or planted. There was also a hefty amount of vibration being transferred through (the whole bike, not just the bars) too. Worsened the faster I went.

 

I rarely have any need to go over 80mph, but I wanted to make sure everything is copacetic with the bike. You never know on a pre-owned..

 

Bike is heading back to the dealer for some other things tomorrow anyway, so I will have them evaluate and report back.

 

thanks!

 

-d

 

"hefty amount of vibration..." does NOT sound normal or good. I'd focus on that, then worry about the floaty sensation. Only time my RT gets a little wonky feeling is when I'm solo with the top case on, in very windy conditions, but it's not as severe as you describe.

 

Sounds like the bike should still be under warranty...I'd whine real loud about the shocks.

[Thylacine]

Bike is heading back to the dealer for some other things tomorrow anyway, so I will have them evaluate and report back.

Good idea. Who knows; there might just be a mechanical issue of some sort. Really though, an RT is a very stable bike at high speeds, so if you're experiencing something different it's likely either mechanical or psychological. What feels rock solid but nimble and responsive to one person, might feel unnerving and unstable to the next — especially given that this was the first time you ran it that fast.

 

See if you can get the shop guys to take it out for a high-speed spin. If it feels good to them, it might just be something that takes some getting used to. For example, my RT is my first bike with the wind-deflecting plastic obscuring the front forks and wheel. At first, not having eye contact with the front part of the bike really threw off my sense of what the bike was doing — especially when turning. I got used to it, though.

[Jon_M]

There was also a hefty amount of vibration being transferred through (the whole bike, not just the bars) too. Worsened the faster I went.

 

Something is definitely not right. Did you buy the bike new? Has it been crashed?

[Jon_M]

I run pressures of 38-40 in the front and 42 in the rear. I have never noticed my RT to be unstable.

This is exactly my experience. I have little need to go over 100 and have only done it on my '05 a couple of times out in the desert. But I frequently cruise in the 90s with no discomfort. It's the most stable bike I've ever owned.

[Jack90210]

I highly suspect the topcase. Did you take it off for today's ride?

[Lmar]

In response to:

Poster: Jack90210

Subject: Re: At what speed does the 12RT become unstable?

 

I highly suspect the topcase. Did you take it off for today's ride?

 

It could be the top case. I never take my top case off when I ride. The RT always feels stable.

[lvmyks]

My 08 is very unstable after I wash it and move it back into the garage with wet shoes. I have been two up, loaded to almost max

GVW and she rides like a Caddillac at 90mph. That is as high as I would go with 2/loaded, straight freeway no one around. Wife and I love 70mph, still slow enough to see the roses.

[chromenomad]

I bought it used, but they assured me it had never been down. (reputable dealer etc etc) Although the windshield is a tiny bit crooked (per another thread here) and the rear plastic is crooked (left bag and signal are 3/4" lower than right, which is what I'm taking it in for tomorrow)

 

I guess it's possible that it was in a wreck that they didn't know about (though they did sell and service it), which could be causing all of these issues.. or it could just be that I'm too used to the old GS and this is all nothing.

 

To answer the other question, no, I didn't remove the topcase (Givi 55L) for today's ride. Trying to change one thing at a time.

 

-d

 

[Jon_M]

or it could just be that I'm too used to the old GS and this is all nothing.

 

Don't assume it's all nothing. Stick with it until you get it sorted out. There is nothing worse than riding a bike you don't trust.

 

Tell the dealer that it feels wonky at high speeds. Do you know anyone else with the same bike? Can you swap bikes and then compare impressions?

[AllenW]

Being a old drag racer I have the need for speed, but considering driver are getting worse as time goes on, I'll advise ya to be careful..

 

Just curious, how long you been riding?

Been a few comments on rider ability here, personally I think ability probably comes more into play when the stuff hits the fan versus just trying to go fast, also I don't really consider 77mph fast enough to cause stability problems in a 1967 450 Honda, much less a BMW unless there were problems with the bike...imho

 

Al

 

 

I bought it used, but they assured me it had never been down. (reputable dealer etc etc) Although the windshield is a tiny bit crooked (per another thread here) and the rear plastic is crooked (left bag and signal are 3/4" lower than right, which is what I'm taking it in for tomorrow)

 

I guess it's possible that it was in a wreck that they didn't know about (though they did sell and service it), which could be causing all of these issues.. or it could just be that I'm too used to the old GS and this is all nothing.

 

To answer the other question, no, I didn't remove the topcase (Givi 55L) for today's ride. Trying to change one thing at a time.

 

-d

[Twisties]

I have ridden mine with the bmw large topcase at full speed, 130 mph or so, without issue, even though I know bmw says to limit speed to 110 mph with the topcase mounted. I assumed any issues would be damage to the topcase. In any event, no instability noted. FWIW. That thing hunkers down so as you could hardly turn it if you needed to.

 

I don't think the dealer will agree to ride it over the speed limit, or at least not admit to it.

 

Best wishes.

[DiverRay]

My '07 with a Givi 55 topcase is STABLE past 110. On the way in to work, I have one mile of road with no traffic, and usually use that area to make sure the bike is "still OK". I don't ride with the bags unless I need them, and I have Pilot tires at 39/41. I am 235 and ride solo most of the time.

I think you must have a mechanical problem with the bike. Make sure the dealer has the mechanic check it out, goes for a test ride, and then report to YOU what he thinks.

[TowJam]

I bought it used, but they assured me it had never been down. (reputable dealer etc etc) Although the windshield is a tiny bit crooked (per another thread here) and the rear plastic is crooked (left bag and signal are 3/4" lower than right, which is what I'm taking it in for tomorrow)

I'm betting that this is related. It's unlikely the bike came from the factory like that. Although it may have not been in an actual "wreck", it sounds like there may have been a drop at some point.

[Dave_C]

this bike is TOO stable at speed. I regularly find myself cruising at 90+ mph, and have to slow down so I don't get a ticket. I've been up up 120mph, and it is very smooth. I usually set the cruise so i don't ride too fast

[tallman]

I bought it used, but they assured me it had never been down. (reputable dealer etc etc) Although the windshield is a tiny bit crooked (per another thread here) and the rear plastic is crooked (left bag and signal are 3/4" lower than right, which is what I'm taking it in for tomorrow)

I'm betting that this is related. It's unlikely the bike came from the factory like that. Although it may have not been in an actual "wreck", it sounds like there may have been a drop at some point.

 

Bingo.

 

Was the bike a trade-in?

Something is fishy.

 

If you bought "used/as is" you may not have recourse, BUT, there is something wrong with the bike if it is out of alignment that much.

I'd try to contact previous owner, ask for accident information.

You might get lucky.

 

If the bike was traded and was OK, and something happened while the dealership "owned" it, you may have some luck.

Wish you had asked here before buying as the issues you cite about plastic and alignment are definite flags.

 

Good luck.

 

[Ponch]

I have the 49L topcase and I will say it's never been an issue. It's a very stable bike and wants to run faster than I can take it yet (still in the break in period). If I had to guess, this bike could cruise at 110-115 all day. Even up to 80-90, it hasn't been a problem...

[longjohn]

this bike is TOO stable at speed. I regularly find myself cruising at 90+ mph, and have to slow down so I don't get a ticket. I've been up up 120mph, and it is very smooth. I usually set the cruise so i don't ride too fast

Haha, what he said.

 

Just a thought here, but could this be a tire balance prob?

[ShovelStrokeEd]

Before you do another thing to the bike, including riding it, get out some tools and check the torque of your rear wheel lugs.

[Kitsap]

Under 3mph gets kind of tricky.

[JayW]

Under 3mph gets kind of tricky.

The obvious and non-controversial answer to the OPs question!

[JOHNNYWISHBONE]

Under 3mph gets kind of tricky.

 

especially if you're really short.

 

either the bike is wrong or the dealer is wrong. or both. you should demand satisfaction or a refund. proper rt's don't wobble. that's why we buy them.

[Penforhire]

Yet another rider here with side bags, large OEM top case that feels his '08 RT is rock-stable up past 120 MPH (indicated). Haven't exceeded maybe 90 MPH since switching to a large Cal-Sci windscreen but it is still very stable.

[Bruce H]

I wouldn't ride a used bike unless I had gone thru it myself. I'd start with the fluids, brakes, cables, tire balance and check the torque of all the bolts I could find, especially any involved in the suspension and wheels. Just because it came from a dealer doesn't mean it was checked before the sale.

[BeemerLover]

Maxed the RT out several times on the Autobahn and it is just as stable at that speed as going 60mph. Things go past a LOT faster which takes some getting used to...

 

 

[Mister Tee]

One thing I've noticed, and maybe it's just me, but the sensation of speed seems to stop around 140 mph. Meaning, you don't seem to be going any FASTER once you pass 140, the numbers on the speedo just grow. (No, an RT won't do 140. I've been up to a true 170 mph in the gsxr a few times, on a closed course. I can get up to about mid 150's on my home track.)

[ShovelStrokeEd]

The next step in stability usually occurs at about 185-190. This is where you find out about things like lift and center of aerodynamic pressure vs center of mass. The latter can cause a yaw like you wouldn't believe. Modern sport bikes, with their fairings mostly modeled after the 200 mph GP bikes are all pretty good these days. Big ol' touring bikes with a spinnaker for a fairing and all sorts of bumps and protrusions behind the rider, not so much.

[I812]

Still waiting for the OP's results........