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There is mis-information being circulated across this and other Forums that the Grand America speed is limited by BMW due to a known stability issue at high speed, which is not true. BMW didn't release the K16B GA for production knowing that it has high speed stability issues. BMW limits the speed on their K1600B Bagger/GA because of the Foot Boards.

If you read the Owners Manual, the reason for the speed limitation is because the Foot Boards do not have Shifter and Brake controls. They view this as a potential safety risk during high speed riding because the Rider has to re-position their feet under emergency situations, which could cause loss of control during very high speed maneuvering. That's why the GTL doesn't have that restriction....it doesn't come standard with Floor Boards.

As far as Grand America susceptibility to air turbulence, it's no different than any other large bike with a windshield and passenger trunk, (especially w/o a passenger). The more surface area the bike has the more it can be affected by air turbulence and cross winds. Did you ever ride a bike with a handlebar mounted wind screen.....lots of fun in high winds and especially behind Tractor Trailers. Throw in some Cross Winds, and you're in for a real treat.
If you're riding behind a Tractor Trailer on your Grand America and the air turbulence makes you nervous, you're in the wrong lane or too close to the Trailer, but you have the option of changing lanes, twist the throttle and say bye-bye.

I don't routinely ride at high speeds with my GA like I did with my Concours 1400, but I've ridden my Grand America to 100 mph a couple of times with no stability issues both in Cruise (soft suspension) mode and Road/Dynamic (stiffer suspension) mode. I'll admit, Road/Dynamic mode handles wind buffeting better than Cruise mode. Even my C14 wiggled behind Tractor Trailers and on windy days at high speeds. It's part of the riding experience. Also some Riders are more sensitive to bike feed back during turbulence than other riders. If it bothers you, slow down and ride at a speed that makes you comfortable. Better yet, get off the Interstate and do some back road curve carving. That's much more fun than riding behind Tractor Trailers.
 

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Thank you for your post I’m sure it will relieve a few people that would be worried BMW has something incorrect about the bike
 

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I am pretty sure it also has to do with the trunk as well. Pop yours open and there is a sticker in there talks about speed. I am away so I can't look at what it says.
 

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Doesn't the front brake lever activate front and rear brakes? So, doesn't that counter the "safety" claim? I could activate both front and rear with the brake lever, never removing my feet from the floorboards. Seems floorboards would be no different that highway pegs.
 

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The top box on the GA is not meant to be removed which is probably why they limit the speed and this speed limiter is consistent with the warnings in the optional/removable top boxes on the GT/GTL.

You would have to ask BMW why the B is limited to ~120 mph. Floorboards are optional on the B, although most have them. Mine does not have them and it came from BMW that way. Although I have yet to test it, I suspect my B is limited to 120 mph and I am OK with that.:eek:ld:

BTW, there are several threads on this.
 

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The top box on the GA is not meant to be removed which is probably why they limit the speed and this speed limiter is consistent with the warnings in the optional/removable top boxes on the GT/GTL.
Even BMW isn’t completely consistent across warnings. My 2019 GT Manual warns me to slow down if I buy the optional top case, and so does the sticker in the case itself, but the sticker advises limiting yourself to a lower speed than does the manual.

Because the GT manual only advises you to ride with caution and common sense when you do NOT have a top case on, you’re free to go as fast as most sane people ever would...so perhaps the GTL topcase should have a second sticker which reads, “If you take this off, however, feel free to go as fast as you want.” >:)
 

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I still don't get the problem with the top box either. My GTL rolls straight as an arrow at 128mph (per GPS, speedo exaggerateds) through most of a tank of gas (but you'll only get about 130-140 miles out of a tank, max, so it doesn't really help much on a long run.) It seemed to be limited to 138mph (per GPS) in Road mode, but for a very brief moment in Dynamic mode it once climbed to 158mph (per GPS), with no noticeable change in handling, and it felt like it had more to give right up until that exact point, which makes me suspect some kind of limiter is still at play.
 

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Even BMW isn’t completely consistent across warnings. My 2019 GT Manual warns me to slow down if I buy the optional top case, and so does the sticker in the case itself, but the sticker advises limiting yourself to a lower speed than does the manual.

Because the GT manual only advises you to ride with caution and common sense when you do NOT have a top case on, you’re free to go as fast as most sane people ever would...so perhaps the GTL topcase should have a second sticker which reads, “If you take this off, however, feel free to go as fast as you want.” >:)
My point was that since the GA top case is "non-removeable", BMW practiced what it preached so to speak and a hard speed limiter was placed on the bike rather than simply putting labels and warnings. They might have opened themselves up to lawsuits and governmental issues by putting a top box on a bike that by their own historical warnings makes the bike less safe above certain speeds and then not limit the bike to a threshold below that certain speed. I am not a lawyer but that sounds like a lawsuit waiting to happen. This is sort of like the Navigation/GPS devices in our cars/trucks that used to just display a warning message and now they simply block you out once you get rolling.
 

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Doesn't the front brake lever activate front and rear brakes? For so, doesn't that counter the "safety" claim? I could activate both front and rear with the brake lever, never removing my feet from the floorboards. Seems floorboards would be no different that highway pegs.
There remains the problem of the shifter which would play a big role in slowdown, dodge, accelerate maneuvers (and many others).

The front brakes are linked but provide proportional braking which is fine most of the time. Note that even while using your front brake you can apply additional rear brake pressure (at least on my bike). The second issue is having to move your feet from the floorboards (unsafe during emergency maneuvers) to a safer position. Highway pegs are the same issue, possibly worse depending on how you mount them.
 

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but for a very brief moment in Dynamic mode it once climbed to 158mph (per GPS), with no noticeable change in handling, and it felt like it had more to give right up until that exact point, which makes me suspect some kind of limiter is still at play.
Warp Factor 8? :)
 

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Since none of us (that I know of) are BMW engineers and we are ALL speculating, I'll throw my .02 in.....
The bagger and GA have different stances than the GT/GTL machines. The rear end sits lower so add a solid floor board on each side in the front and you'll get aerodynamic forces pushing the front end of the bike up which decreases the stability of the bike as you increase speed. Add the top case and the rear end feels even heavier.
This is what makes the machine start to get unstable at higher speeds. The entire industry has to lean toward the "safety first" end of things so limiting the bike to whatever the speed is makes the lawyers feel better about things.
 

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So it's safe at 105 mph but not at 110 mph?
Pre-apologizing for the semi-rant, and not a response to you @Arizona Jim but keying off of your comment..

Aerodynamically speaking.. yes. A wing will stall below a certain speed and create lift above that speed (as a gross example). The envelope of low pressure air created by the windscreen moves backward as you accelerate, lengthening. The more vertical the windscreen the greater the height of that bubble and the higher the density gradient between low and high pressure areas (greater the pressure differential) behind the windscreen and the greater the resulting turbulence (TANSTAAFL). Anecdotally at some point you feel some of this as backpressure. Moving further up the speed spectrum you transition between direct pressure on the front of the top box to probably lowering the air pressure around the top box and during this transition you probably get a bit of both, we have had people refer to this as a Von Karman vortex (highly unlikely but it is turbulence). Everyone here would call it buffeting but its just turbulence created by the profile of your particular setup in the air stream.

Yes all of that will happen at very specific speeds. Here is where the inconsistency of both anecdotal evidence and BMW no doubt rigorous testing will give you a great big fuzzy margin of error.

We have heard numerous statements of people saying that they have ridden bike x at vvv speeds (always well above normal highway speeds) and the reports always fall along that gradient of little to no problems. Then you have people reporting that even at highway speeds when in dirty air (behind a truck) they experienced instability.

BMW on the other hand, most likely in their vast collection of experience has to limit testing to the attainable test parameters and shoot for some level of reproducible and plausible worst case scenario(s). Meaning that they probably do not test for the extremes (hurricane force winds, baseball size hail, absolutely perfect weather). They would restrict their tests to finding the margin of safety under normally adverse conditions. Taking off the product designer hat for a second. This is just pragmatic engineering as anything beyond that would be silly, BMW has to pick a rider weight, size, environmental conditions , etc that they can successfully test for.

Now going back to the point about aerodynamics, on top of pure aero profile you also have weight (pilot, gross vehicle, etc), tire pressure, suspension condition, tire choice, windscreen position, weight distribution, presence of a pillion and their weight, etc.. Then you have road conditions, wind conditions, and the aerodynamic envelope that is around you.

All of these variables are going to create specific and different outcomes. Having a pillion for instance creates an additional bias towards weight, loading the suspension (could be good or bad) and changing the aerodynamic envelope (probably good except for extreme cases). It is very difficult to reproduce testable results across the board for an almost infinitely wide range of physical variables. BMW has the same anecdotal evidence that we (the unwashed public) have available but in the interest of placating the lawyers and providing a margin of safety they are forced to pick a path, do the testing for which they determine that under their testable conditions there is a problem. Because of the results of that test, we get a sticker, a warning paragraph, and a speed limiter. And this is where the conflict of opinion occurs, it is when public anecdotal evidence contrasts with BMWs testable and reproducible parameters. We end up with the preponderance of anecdotal evidence on the forums and in life where we are 'live testing' for a set of parameters that BMW is fully aware of but because of all of the external influences (lawyers, lawyers and lawyers) they are forced to downplay and mandated to focus on what is known to cause problems. Does this mean BMW is wrong.. f* no, they are good engineers, they know what they are talking about. Is this a predictable result for every rider, again.. no because of all of the variables. BUT.. everyone should be aware that there is at least one set of known, reproducible parameters that will cause a problem and everyone should believe it because 'why in the heck would bmw self limit the marketable attributes of the bike otherwise'.

For those that are experiencing instability behind trucks. Back off, downshift, go around, lower your windscreen, raise your windscreen, take off the top box, tuck down, sit up, change something so that you are not in that state - because at some level your riding style, profile, etc, something about the physical aspects of your current state is exacerbating the problem. Be aware that riding too close to a truck and you could be anywhere from inside their low pressure envelope to highly turbulent air, to clean air if you are far enough back. For those that are not having the problem (despite the warning labels) know that the problem could happen, BMW can prove it so they have limited the top speed. Will it happen, probably not but you just never know so at minimum be aware.

The hyperfocus on this problem is creating a near hysteria in some cases as bookends of experience to what we know is the truth about motorcycles. They are inherently unstable, dangerous, and they (and you the reader) are a constantly live experiment in exploring the boundaries set by your skills, your vehicle, and the environment you ride in. The only influence you have (we have) is to improve those things that you have control over such as your skills, the condition of your ride, and when/where you choose to ride. You (we) are in control here and the last thing anyone should do is expose themselves to the uncontrollable. So ride, go out and ride and enjoy what you have, improve your skill, be aware, take control, but know that nobody else's 'experiement' applies 100% to you so adapt, relax, and enjoy... or drive a car. Just sayin'
 

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Pre-apologizing for the semi-rant, and not a response to you @Arizona Jim but keying off of your comment..

Aerodynamically speaking.. yes. A wing will stall below a certain speed and create lift above that speed (as a gross example). The envelope of low pressure air created by the windscreen moves backward as you accelerate, lengthening. The more vertical the windscreen the greater the height of that bubble and the higher the density gradient between low and high pressure areas (greater the pressure differential) behind the windscreen and the greater the resulting turbulence (TANSTAAFL). Anecdotally at some point you feel some of this as backpressure. Moving further up the speed spectrum you transition between direct pressure on the front of the top box to probably lowering the air pressure around the top box and during this transition you probably get a bit of both, we have had people refer to this as a Von Karman vortex (highly unlikely but it is turbulence). Everyone here would call it buffeting but its just turbulence created by the profile of your particular setup in the air stream.

Yes all of that will happen at very specific speeds. Here is where the inconsistency of both anecdotal evidence and BMW no doubt rigorous testing will give you a great big fuzzy margin of error.

We have heard numerous statements of people saying that they have ridden bike x at vvv speeds (always well above normal highway speeds) and the reports always fall along that gradient of little to no problems. Then you have people reporting that even at highway speeds when in dirty air (behind a truck) they experienced instability.

BMW on the other hand, most likely in their vast collection of experience has to limit testing to the attainable test parameters and shoot for some level of reproducible and plausible worst case scenario(s). Meaning that they probably do not test for the extremes (hurricane force winds, baseball size hail, absolutely perfect weather). They would restrict their tests to finding the margin of safety under normally adverse conditions. Taking off the product designer hat for a second. This is just pragmatic engineering as anything beyond that would be silly, BMW has to pick a rider weight, size, environmental conditions , etc that they can successfully test for.

Now going back to the point about aerodynamics, on top of pure aero profile you also have weight (pilot, gross vehicle, etc), tire pressure, suspension condition, tire choice, windscreen position, weight distribution, presence of a pillion and their weight, etc.. Then you have road conditions, wind conditions, and the aerodynamic envelope that is around you.

All of these variables are going to create specific and different outcomes. Having a pillion for instance creates an additional bias towards weight, loading the suspension (could be good or bad) and changing the aerodynamic envelope (probably good except for extreme cases). It is very difficult to reproduce testable results across the board for an almost infinitely wide range of physical variables. BMW has the same anecdotal evidence that we (the unwashed public) have available but in the interest of placating the lawyers and providing a margin of safety they are forced to pick a path, do the testing for which they determine that under their testable conditions there is a problem. Because of the results of that test, we get a sticker, a warning paragraph, and a speed limiter. And this is where the conflict of opinion occurs, it is when public anecdotal evidence contrasts with BMWs testable and reproducible parameters. We end up with the preponderance of anecdotal evidence on the forums and in life where we are 'live testing' for a set of parameters that BMW is fully aware of but because of all of the external influences (lawyers, lawyers and lawyers) they are forced to downplay and mandated to focus on what is known to cause problems. Does this mean BMW is wrong.. f* no, they are good engineers, they know what they are talking about. Is this a predictable result for every rider, again.. no because of all of the variables. BUT.. everyone should be aware that there is at least one set of known, reproducible parameters that will cause a problem and everyone should believe it because 'why in the heck would bmw self limit the marketable attributes of the bike otherwise'.

For those that are experiencing instability behind trucks. Back off, downshift, go around, lower your windscreen, raise your windscreen, take off the top box, tuck down, sit up, change something so that you are not in that state - because at some level your riding style, profile, etc, something about the physical aspects of your current state is exacerbating the problem. Be aware that riding too close to a truck and you could be anywhere from inside their low pressure envelope to highly turbulent air, to clean air if you are far enough back. For those that are not having the problem (despite the warning labels) know that the problem could happen, BMW can prove it so they have limited the top speed. Will it happen, probably not but you just never know so at minimum be aware.

The hyperfocus on this problem is creating a near hysteria in some cases as bookends of experience to what we know is the truth about motorcycles. They are inherently unstable, dangerous, and they (and you the reader) are a constantly live experiment in exploring the boundaries set by your skills, your vehicle, and the environment you ride in. The only influence you have (we have) is to improve those things that you have control over such as your skills, the condition of your ride, and when/where you choose to ride. You (we) are in control here and the last thing anyone should do is expose themselves to the uncontrollable. So ride, go out and ride and enjoy what you have, improve your skill, be aware, take control, but know that nobody else's 'experiement' applies 100% to you so adapt, relax, and enjoy... or drive a car. Just sayin'
Great write up, seriously.
Thanks, now let's get out there and ride.
 

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My dad always said to me and after riding for like 40 years, motorcycle riders should reach the destination later all intact than sooner on a stretcher. I have to say, I am soooo happy with this bike even if the speed is limited to 105 on my GA. Even if I want to do 140, I have no way to achieve it here in NJ. Speeding tickets are brutal here points and money wise. I did 140 on my ex GTLE in PA and it was just ok for me. Doing 80 - 85 maybe 90? is so much fun too for me. We all need to relax and enjoy the view around us. I love looking at nature and looking at my black beauty as I ride. I have enough stress at work at times, commuting on her is a pleasure at average 80. Even if tomorrow BMW will change the mapping on the B/GA to unlimited speed, I will be the last rider to go to do it. Happy slow motion riding to all !!!!
 

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the B is limited to ~120 mph
Stock, it is at 130 mph indicated (which is ~126 mph actual, according to GPS). Yes, I tested it.

With the limiter gone (BrenTuning flash), have had the B up to 139 indicated, with feet out on the floorboards. Had no stability issues.
 

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All BMW RT, GT, etc top cases have the speed limit warning label.

Duane
And since the same top case can be used across several models, I'm sure they've gone for a warning which constitutes the lowest of any of the potential models, but why not list the models and various speeds at that rate, OR just put the lowest speed any model with topcase needs in every model's manual.

That's the type junk lawyers can exploit, and this is not an expensive item to cure. In risk management, when in doubt, consistency is king, and for people who know how to ride, they can sense when the bike begins to feel unstable, and will back off the throttle, and slow down, even if they're at a speed which is slower than the manual or sticker says they can go. When I once had a weird situation behind a semi, and with wicked, fast, pulsing crosswinds, and with the topcase, I slowed to 75 mph at one point, which is slower than either the manual or case sticker said I could go.

I know fully why they can't do it, but in a sane world, they'd be able to say, "If your butt tells you the bike isn't stable at whatever speed you're traveling, regardless of what bike you're riding or how it's equipped, then roll off the throttle until it DOES feel stable, you doofus!"

In contrast, if my bike feels solid as a rock at whatever speed and I'm comfortable, I couldn't care less if I'm going faster than what the manual or whatever warning says.
 

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Happy slow motion riding to all !!!!
I love freedom and your ability to ride your ride, however you want, but...that's my problem. I can't be happy when riding in slow motion. Riding in slow motion ain't fun, and fun riding ain't in slow motion. :grin:
 

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Pre-apologizing for the semi-rant, and not a response to you @Arizona Jim but keying off of your comment..

Aerodynamically speaking.. yes. A wing will stall below a certain speed and create lift above that speed (as a gross example). The envelope of low pressure air created by the windscreen moves backward as you accelerate, lengthening. The more vertical the windscreen the greater the height of that bubble and the higher the density gradient between low and high pressure areas (greater the pressure differential) behind the windscreen and the greater the resulting turbulence (TANSTAAFL). Anecdotally at some point you feel some of this as backpressure. Moving further up the speed spectrum you transition between direct pressure on the front of the top box to probably lowering the air pressure around the top box and during this transition you probably get a bit of both, we have had people refer to this as a Von Karman vortex (highly unlikely but it is turbulence). Everyone here would call it buffeting but its just turbulence created by the profile of your particular setup in the air stream.

Yes all of that will happen at very specific speeds. Here is where the inconsistency of both anecdotal evidence and BMW no doubt rigorous testing will give you a great big fuzzy margin of error.

We have heard numerous statements of people saying that they have ridden bike x at vvv speeds (always well above normal highway speeds) and the reports always fall along that gradient of little to no problems. Then you have people reporting that even at highway speeds when in dirty air (behind a truck) they experienced instability.

BMW on the other hand, most likely in their vast collection of experience has to limit testing to the attainable test parameters and shoot for some level of reproducible and plausible worst case scenario(s). Meaning that they probably do not test for the extremes (hurricane force winds, baseball size hail, absolutely perfect weather). They would restrict their tests to finding the margin of safety under normally adverse conditions. Taking off the product designer hat for a second. This is just pragmatic engineering as anything beyond that would be silly, BMW has to pick a rider weight, size, environmental conditions , etc that they can successfully test for.

Now going back to the point about aerodynamics, on top of pure aero profile you also have weight (pilot, gross vehicle, etc), tire pressure, suspension condition, tire choice, windscreen position, weight distribution, presence of a pillion and their weight, etc.. Then you have road conditions, wind conditions, and the aerodynamic envelope that is around you.

All of these variables are going to create specific and different outcomes. Having a pillion for instance creates an additional bias towards weight, loading the suspension (could be good or bad) and changing the aerodynamic envelope (probably good except for extreme cases). It is very difficult to reproduce testable results across the board for an almost infinitely wide range of physical variables. BMW has the same anecdotal evidence that we (the unwashed public) have available but in the interest of placating the lawyers and providing a margin of safety they are forced to pick a path, do the testing for which they determine that under their testable conditions there is a problem. Because of the results of that test, we get a sticker, a warning paragraph, and a speed limiter. And this is where the conflict of opinion occurs, it is when public anecdotal evidence contrasts with BMWs testable and reproducible parameters. We end up with the preponderance of anecdotal evidence on the forums and in life where we are 'live testing' for a set of parameters that BMW is fully aware of but because of all of the external influences (lawyers, lawyers and lawyers) they are forced to downplay and mandated to focus on what is known to cause problems. Does this mean BMW is wrong.. f* no, they are good engineers, they know what they are talking about. Is this a predictable result for every rider, again.. no because of all of the variables. BUT.. everyone should be aware that there is at least one set of known, reproducible parameters that will cause a problem and everyone should believe it because 'why in the heck would bmw self limit the marketable attributes of the bike otherwise'.

For those that are experiencing instability behind trucks. Back off, downshift, go around, lower your windscreen, raise your windscreen, take off the top box, tuck down, sit up, change something so that you are not in that state - because at some level your riding style, profile, etc, something about the physical aspects of your current state is exacerbating the problem. Be aware that riding too close to a truck and you could be anywhere from inside their low pressure envelope to highly turbulent air, to clean air if you are far enough back. For those that are not having the problem (despite the warning labels) know that the problem could happen, BMW can prove it so they have limited the top speed. Will it happen, probably not but you just never know so at minimum be aware.

The hyperfocus on this problem is creating a near hysteria in some cases as bookends of experience to what we know is the truth about motorcycles. They are inherently unstable, dangerous, and they (and you the reader) are a constantly live experiment in exploring the boundaries set by your skills, your vehicle, and the environment you ride in. The only influence you have (we have) is to improve those things that you have control over such as your skills, the condition of your ride, and when/where you choose to ride. You (we) are in control here and the last thing anyone should do is expose themselves to the uncontrollable. So ride, go out and ride and enjoy what you have, improve your skill, be aware, take control, but know that nobody else's 'experiement' applies 100% to you so adapt, relax, and enjoy... or drive a car. Just sayin'
As a longwinded poster myself, I feel compelled to like this post, and I also agree, but I am also keeping it to show to H-D people who ask how a BMW forum could be different from one of theirs (unless it's to talk about counting all our money, hahaha [many H-D folks labor under the huge mis-impression we're all rolling in the dough]), that this is the level of educated discourse we enjoy around these here parts. :grin:
 
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