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Bringing RT grips closer with K16GTL adjustable handlebars

mneblett

#32806
This is not a "how to" but is intended merely to document what I've done in case it is useful to someone in the future. Unfortunately, it will also be long!

I am 5'7", 29.5" inseam, and have too-short arms for an RT. The stock bars are perfect for some, but too far forward for me. The resulting leaning-forward position becomes uncomfortable pretty quickly. I installed bar risers which brought the grips up, lessening my lean, but not much back. The design of the stock "bars" and the locations of the clutch and brake master cylinders' outlets severely hamstring aftermarket bar riser vendors' options.

BMW Cockpit shot.jpeg

I like the RT enough that I decided it was worth the effort to try something new. I heard recently that BMW now offers an RT tubular handlebar option. A bit of digging around allowed me to find that the upper triple tree ("upper fork cross brace" in BMW-speak) used on the tubular bar RT is essentially (if not exactly) identical to that on a GS. I was able to use an earlier R1200GS triple tree that I picked up off fleabay for $125 shipped from Latvia (part no. 31 42 8 555 851), with the steering stem bearing and fork leg flexible bushings in excellent shape (similar but cleaner than the one below). $125 beats nearly $900 new from BMW.

Tubular bar triple tree.jpg

The next issues were which replacement handlebar to use, and how to bridge the gap between the 32mm OD of the BMW tubular bars and a different replacement bar OD. Based on previous experience with one of my GTLs, I opted for Helibars K1600GTL Horizon adjustable bars. Not a cheap option, particularly knowing that I would not be using the very nice adaptor brackets Helibars manufactures to permit the K16 steering head to accept their tubular handlebar center section. I winced and paid the price because I knew that the Horizon bars are so adjustable that I should be able to very precisely tailor the grip angles to suit my OCD.

K16GTL Horizon Helibars.jpeg

The next issue was how to go from the 32mm BMW handlebar OD to the Helibars K16GTL 1" center section OD. I looked everywhere but could not find a 32mm-to-1" adapter. However, I stumbled on a set of Rox risers that I thought I could modify to do the job. Their flat bases were a plus to me. The Rox part no.:

Rox part number.jpeg

These risers have a base which is slotted to fit 31mm-42mm mounting bolt separations, and uses split shell adapters to enable mounting of either 7/8" or 1 1/8" handlebars. https://roxspeedfx.com/products/1-1...for-7-8-or-1-1-8-handlebar?variant=1031362021
Rox risers picture.jpeg
Unfortunately, the mounting bolt separation for BMW 32mm tubular handlebars is 44mm. The solution was to use my milling machine to elongate the Rox slot 2mm while maintaining the lower step that the bolt head uses to clamp the riser to the triple tree. I had to get closer to the threaded portion for the top clamp than I would have liked, but there's enough meat left that the fastener load on the threads is adequately supported.

Elongated slot.jpeg

Fitting the 1" K16GLT Helibar center section was handled by using my lathe to bore a hole in a 2" Aluminum bar I had laying around in steps up to 1", and then reducing the OD until it fit the curvature of the Rox parts well. The rough surface finish is intentional to enhance the grip on the handlebar once clamped down.

Adapter ring boring.jpegTurning down adapter ring OD.jpeg

Fitting to Rox ID.jpegChecking fit.jpeg

After cutting the rings off to width from the turned tube, they were split and their ends sanded down on a belt sander to ensure they would not meet one another when installed, i.e., prevent the shell halves forming a complete circle which would keep the clamping force away from the 1" handlebar. One of the Rox shell halves for fitting a 7/8" bar is included in the pic below for size comparison.

Slided and trimmed shells ready to install.jpeg

Onward to assembly!

Removal of the stock upper triple tree does not cause the Telelever suspension to collapse, as the front shock supports the frame against the lower A-arm. I did place a jack under the engine just in case, but more to stabilize the entire bike while I was working. Note that the steering stem bolt is a T55 Torx, and it is thread-locked. It actually was not that hard to get to release. Just make sure the T55 bit is fully inserted before applying force.

No upper triple clamp.jpeg

Removal of the fuel tank and the air box is not *required* to do this job, but it would be miserable with them in place.

Note in the above pic that (1) I've released the hoses and cables from their tie-down points near the steering head (e.g., the fat "T" on the right side of the upper frame tube); and (2) I've rotated the stock triple tree and ignition module to the rear side of the steering head. The ignition module is factory secured from the bottom by security screws whose heads must be drilled off in the same manner as you would remove a rivet head. To mount the ignition module to the replacement triple tree, you can either go to BMW and buy replacement security screws and their special installation tool, or use appropriate-length 6mm Allen head bolts which fit neatly into the module and triple tree.

Ignition module underside.jpegIgnitiion module replacement bolts.jpeg

My thought is that a bad guy easily removing the bolts is not an issue, as (i) BMW touring bikes are not a desirable target to sport bike-craving joyriders, and (ii) even if a professional thief knows about the BMW security bolts (or even my "easily" removable Allen bolts), as a practical matter the bolts are nearly impossible to access when in the bike. If a thief has actually made off with my bike and taken it apart far enough to get to my bolts, more power to them -- I wouldn't want the bike back then.

A few times on and off for test-fitting and adjustment, and things began to come together:

Modified bases in place.jpegBars test fit 2.jpeg
Bars test fit with grips.jpeg

Note that when I removed the stock upper triple tree I moved all of the hoses and cables to behind the steering head. Coupled with the freeing of the hoses/cables from their restrictive factory tie-downs, this allowed me to continue to use the stock hoses/cables without extensions or replacement. I was very careful throughout the multiple fittings/adjustments to ensure that no hose or cable was over-stretched or crushed at full lock to either side.

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Left hose full right lock.jpegLeft hose full left lock.jpeg
Right hose full right lock.jpegRight hose full left lock.jpeg

The tightest of the hoses/cables is the brake line when at full right lock, when it tucks into the space between the steering head and the right fork leg. A bit of careful routing and cable-tying resulted in an acceptable-to-me amount of curvature. The bike also is not at full right lock very often, so this hose should not be overstressed over its life. Nonetheless, I will keep an eye on it as I go forward.

The final assembly looks like this (ignore the ugly mug in the rider's eye view shot, as well as the messy garage in front of the bike!):

Final headstock view with BMW emblem.jpegRider eye view.jpeg

I was concerned that this Erector Set of a project might turn out hideous, but it looks relatively clean, if somewhat busy, to me -- some certainly may think otherwise. However, the bottom line is that I now have ergonomics on this bike that match my undersized body so I can sit fully upright, so I don't really care how they look!

These pics are not a good match, but they give an idea how much farther back the grips have moved:

Stock handlebar side view.jpegSide view of grips relative to tank.jpeg

In sum, this is not intended to encourage others to do this, as a nicely-equipped home garage and a lathe and milling machine are not available to most. That said, if one is willing to jump into the deep end to make the bike *exactly* fit them, this should at least show that us short-armers have an option.
 
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Quite a project, nice you were able to make your RT work better for you. You invested quite a lot of time and money into this. I have used my own milling machine and lathe to make motorcycle mods and gear, but am glad I don't need to modify my own RT in this way and am happy with the stock bar position for me. It is nice to have the tools and skills to use them.
 
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