BMW K bikes (Bricks)

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AJ.Valente

AJ.Valente
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After taking a long look at the RT it seems the designers created options to accommodate rider height, only this is not reflected in the literature. Almost from the beginning there were reports of wind noise at high speed, a condition for which BMW seemingly had no answer. In actuality, the adjustment is a rather small and often goes overlooked.

Upon examining dozens of marketing photos, assembly instructions, contemporary articles, etc., one thing stands out--RT handlebars were set by the factory to the highest position, about 7-9" above the faring lip. An upright posture was deemed natural for touring, and since the RT was the "touring" model, this was probably why the bars were initially set so high. As handlebar adjustment isn't mentioned in the assembly instructions or the rider's manual, it seems most people accepted the factory settings without question.



(Figure 1) Faring concepts on RS and RT are very similar. In this artist drawing (modified for content) RS and RT are pictured side-by-side with streamlined fairings mounted at similar angles (note that handlebar heights are much the same). The RS windscreen ends just before the handlebars, while the RT windscreen extends further back and covers the handlebars.

The RS design called for fixed handlebars with an adjustable windscreen to match the height of the rider, while the RT was just the opposite with a fixed windscreen and adjustable handlebars.

Ideal adjustment to the windscreen(s) essentially requires the rider just peer over the lip of the canopy. On the RS a small windscreen extension may be raised or lowered, and the RT the range of handlebar adjustment is only about 3", but this small change makes all the difference in the world. Thus, on the RT taller riders will slide back in the seat, lean forward a bit, and lower the handlebars to a suitable position, while shorter riders will slide forward in the seat and adjust the handlebars up to a comfortable level.

continued . . .


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'98 K1200RS Marrakesh Red

My old K100 RT Pics and Mods
    

AL-58

AL-58
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Its one of the first things I adjust on any bike I get.  Adjust the bars, not so much for height but for the angle of the bars at my hands, then adjust the clutch/brake so the levers sit at the right height for me.

I had an R1100GS at one stage, the po was much taller than me, until I readjusted the bars it gave me a huge pain in the upper back. It was only a 6-month bike for me in the end.

Al


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'87 K100RS/HRD sidecar (1100 motor)  sc25 
'92 K100RS-16v (Paint it Black)

'87 K100RT with Paralever backend

"When I'm too old and too foolish to handle a sidecar I'll buy a Sportsbike"

K100RT Ergonomics and Handlebar Adjustments K-dogs10
    

AJ.Valente

AJ.Valente
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PLEASE NOTE: The writer stands 5'11" (176cm) tall, so ergonomic drawings that follow assume a rider of average height, between 5'10" and 6' tall.

After riding my '85 RT for 2 years and some 12K miles with handlebars at the highest setting I came to the conclusion that something was not right. Mostly I had to lower my head every time in order to read the instruments, but also the brake and clutch levers partially blocked the view in the mirrors. In addition, my knees ached tremendously on long rides, so during the winter of 2013-14 I began some experiments to see what, if any, improvements could be made . . .

The motorcycle economics web site (http://cycle-ergo.com/) illustrates my problem--sticking up too far over the windscreen.



(Figure 2) (left) Standard riding position generates lots of wind noise at speed. (right) But, I noticed that by scrunching down somewhat (arm straightness at 60deg) one could get into the slip stream where it is very quiet. Unfortunately, this position cannot be maintained for very long.

So, what to do?

continued . . .


__________________________________________________
'98 K1200RS Marrakesh Red

My old K100 RT Pics and Mods
    

duck

duck
Life time member
Life time member
Get a taller windscreen?


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Current stable:
86 Custom K100 (standard fairing, K75 Belly pan, Ceramic chromed engine covers, paralever)
K75 Frankenbrick (Paralever, K11 front end, hybrid ABS, K1100RS fairing, radial tires)
86 K75C Turbo w/ paralever
94 K1100RS
93 K1100LT (x2)
91 K1
93 K75S (K11 front end)
91 K75S (K1 front end)
14 Yamaha WR250R
98 Taxi Cab K1200RS
14 K1600GT
http://www.ClassicKBikes.com
    

Two Wheels Better

Two Wheels Better
Moderator
Moderator
@AJ.Valente wrote:The RS design called for fixed handlebars with an adjustable windscreen to match the height of the rider, while the RT was just the opposite with a fixed windscreen and adjustable handlebars...On the RS a small windscreen extension may be raised or lowered, and the RT the range of handlebar adjustment is only about 3", but this small change makes all the difference in the world. Thus, on the RT taller riders will slide back in the seat, lean forward a bit, and lower the handlebars to a suitable position, while shorter riders will slide forward in the seat and adjust the handlebars up to a comfortable level.

continued . . .
I've not been aware of factory fitted 'adjustable' handlebars, per se, on an RT, except that the clamps can be loosened and the 'bars spun forward or backward a few degrees like almost any round-section handlebar, including the RS. This helps with angle, but not very much with height. The range of tilt is greater on the RT than the RS, of course, but adjustment is quite limited on both types of 'bars. I think I get what you mean by adjustment, but felt the need to attempt to clarify. To my mind adjustment means height as well as angle, and neither of the two types of 'bars have that. Adding 'bar risers of various dimension will give a bit more range of adjustment. I have 25mm risers on my RS, as well as internally-mounted extenders which make the 'bars about 30mm longer at each end, and which give me more comfort with their wider spacing and a more relaxed position as they extend up and back towards me a few millimetres as well.


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Sometimes I lie awake at night, and I ask, "What can I do to keep my life from going by so fast?" Then a voice comes to me that says, "Try slowing down at the corners." 

~Charlie Brown

1970 R60/5, '77 R75/7-R100, '85 K100'87 K75C, '87 K100RS, '93 K11-K12 Big Block, '93 K1100RS, '95 R100-Mystic, '96 K1100RS, '98 K1200RS, '00 K1200RS, '02 K1200RS, '03 K1200GT, '04 R1150R'04 R1150RT, '05 K1200S, '06 K1200R, '07 K1200R, '09 K1300GT & 2013 R1200RT-Polizei  - Beemers owned still or sold.

    

brickrider

brickrider
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I completely agree that adjustment is pretty limited, but I hasten to add that on my RS bikes (K and R100) a slight adjustment makes a surprising difference. A few degrees off and I have discomfort in my wrists. 
As an historical note, during the 1980s Laverda was the leader of the pack in terms of recognizing that one size does not fit all.  Laverda had bars that were truly adjustable.  Foot rests too, most especially on the bikes with the 120 degree engines.

    

Guest

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The 1977 R75/7 had adjustable footrests and I suspect so did many bikes before that.

    

AJ.Valente

AJ.Valente
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Finally, it occurred to me that if the bike's handlebars were somewhat lower I might be able to ride in the slip stream all of the time.



(Figure 3) To test this new theory I took sections of rubber tubing and hung them a distance of  about 3-4" below the regular grips (arrows). Now sitting on the bike with helmet on I changed my hands to the lower position. I had to lean forward a bit, but did not come too near the windscreen. All felt comfortable, the mirrors came into 100% view, and I could now peer over the windscreen and view the instruments simultaneously without any head movement. Furthermore, I could now slide back in the seat to an even more comfortable position.



(Figure 4) Working out the ergonomics; (left) With normal arm straightness (85deg) and handlebars lowered by 3.5", the rider experiences a 16deg forward lean. (right) Next, by sliding backwards in the seat about 2" increases lean to 22deg and establishes a comfortable position within the slip-stream. (Note: The software doesn't permit this on the RT, so rider's figure and accompanying numbers were transposed from the K75 model.)

continued . . .


__________________________________________________
'98 K1200RS Marrakesh Red

My old K100 RT Pics and Mods
    

AJ.Valente

AJ.Valente
Life time member
Life time member
The next step is to adjust the handlebars to an appropriate setting for a rider of my height. Since there is no guideline from BMW,  I chose to start at the lowest setting and try that out for a year to see how it feels.



(Figure 5) (left) The lowest RT handlebars can be set is 3.5" above the faring lip. Levers and controls must be repositioned by rotating to appropriate angles for proper operation and also clear the faring. (right) Factory photo of the (rare) green late model RT ('89) w/ABS. Notice that with no panniers and lower handlebars this bike is set up for road action just like an RS. (Note; clutch lever is horizontal while in practice it will be at a downward angle.)

It seems that manufacturing eventually got the memo and began setting RT handlebars to levels suitable to average riders.

A maintenance issue with lower handlebar positions is they exert greater force on the rubber mounts and this may result in unwanted play. Simply torquing the mounting nuts has little effect as it only deforms the bottom washer and causes the mount bolt to shear off. (see https://www.k100-forum.com/t700-rt-handlebar-mounts) Alternatively, a 1" thrust washer is placed under the bottom washer virtually eliminates handlebar play. (see https://www.k100-forum.com/t700-rt-handlebar-mounts)

continued . . .


__________________________________________________
'98 K1200RS Marrakesh Red

My old K100 RT Pics and Mods
    

AJ.Valente

AJ.Valente
Life time member
Life time member
Of course, a canyon style seat is none too conducive to forward lean, so one must use a bench seat or something like the "gunfighter" style.



(Figure 6) (left) The compound curves of RT handlebars rise gradually from the triple tree, then fall-off gracefully to each side. (right) The grips come readily to hand, and from this view the rider position looks most inviting. The Corbin gunfighter seat accommodates forward lean while providing added freedom of movement and comfort on long rides.

In the final analysis, the K100RT is a quick and fast road bike that weighs just 10 pounds more than the RS. Conversion to sport-touring is really easy, by dropping the handlebars down a few inches the rider goes into a mild forward lean* that lowers the center of gravity, reduces drag, and improves both handling and braking. The forward rider angle also equalizes weight distribution and takes pressure off knee joints for greater comfort over the long haul.

Is this what the designer's originally had in mind for the RT?

Enjoy the ride.

-AJ

*=Lowering the RT handlebars produces a 22deg lean vs 32deg on the RS for similar rider and rider position.


__________________________________________________
'98 K1200RS Marrakesh Red

My old K100 RT Pics and Mods
    

duck

duck
Life time member
Life time member
@AJ.Valente wrote:Of course, a canyon style seat is none too conducive to forward lean, so one must use a bench seat or something like the "gunfighter" style.

Balderdash!

K100RT Ergonomics and Handlebar Adjustments DSC01687


__________________________________________________
Current stable:
86 Custom K100 (standard fairing, K75 Belly pan, Ceramic chromed engine covers, paralever)
K75 Frankenbrick (Paralever, K11 front end, hybrid ABS, K1100RS fairing, radial tires)
86 K75C Turbo w/ paralever
94 K1100RS
93 K1100LT (x2)
91 K1
93 K75S (K11 front end)
91 K75S (K1 front end)
14 Yamaha WR250R
98 Taxi Cab K1200RS
14 K1600GT
http://www.ClassicKBikes.com
    

RicK G

RicK G
VIP
VIP
Most of the guys in Australia with an RS have the comfort seat or similar style Corbin. I would say that having a Gunfighter style is far from necessary and having a bench seat well I am not into the BDSM sort of thing


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"Man sacrifices his health in order to make money.
Then he sacrifices money to recuperate his health.
And then he is so anxious about the future that he does not enjoy the present; the result being that he does not live in the present or the future; he lives as if he is never going to die, and then dies having never really lived."   Dalai Lama


Bikes 1998 K1100 LT, 1993 K75 RT, 1996 K75RT, 1986 K75 GS, 1979 Z1300 Kawasaki
    

AJ.Valente

AJ.Valente
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Life time member
Apples  Smile and oranges  Cool .

The RS has shorter handlebars, so the ergonomics is quite different.

Here we're talking RT where the handlebars are much longer (imagine a set of RT bars on an RS). To effect a lean of 20deg or more one must slide back in the seat, and a canyon won't allow that.

For example, here's a bike from down under:



The above RT is set-up properly. The handlebars are lowered (lower than the mirrors) and it has a bench seat. This is a rare black RT, and the owner who posted this picture on the board swears by it.


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'98 K1200RS Marrakesh Red

My old K100 RT Pics and Mods
    

Avenger GT

Avenger GT
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AJ, if those are supposed to be links to pictures you are putting up, they are not working for me.

    

AJ.Valente

AJ.Valente
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@Avenger GT wrote:AJ, if those are supposed to be links to pictures you are putting up, they are not working for me.
Not links, just posted pictures. See the admin if you're having problems viewing them.

Thanks,

-AJ


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'98 K1200RS Marrakesh Red

My old K100 RT Pics and Mods
    

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