Drop bars and Gilles Berthoud's twister. Shim?

[keleher]

I have a Nitto Noodle and just got Gilles twister shifter. The shifter fits fine, but the noodle has a center bulge to 26.0 mm. The supplied shim won't fit over this (stopped about an inch from the clamp), though the shifter works fine there.

I'm wondering if there is anything else to use as a shim.

Alternatively, I could conceivably go without a shim. The shifter is designed to clamp onto the shim. However, if you note the spikes that the shifter has in the picture, I could conceivably clamp directly to the handlebar. This would be inelegant. Also, while the shim is aluminum, the bar is steel, so I'm not sure how well it would even grip.

Any ideas for another shim?

[Danneaux]

Hi Keleher!

I'm sorry your question has not been answered. If you have not yet solved the problem, I have a suggestion for your consideration:

Might it be possible to use an end-mill or even a common hole saw, and re-mill the hole in the shim off-center? I realise the hole in the shim needs to be larger, but not by much -- about the thickness of the difference between the center bulge and the handlebars. If the shim could be securely clamped and the end-mill cut no closer to the thin end of the shim, there appears to be plenty of stock to enlarge the opening toward the thick end. This would avoid clamping the shifter directly to the steel handlebar.

Clamping the item securely for machining would be the bigger challenge, but I've had great success in re-milling MTB-sized components (shifter pods, re-forged and re-contoured brake levers) to fit on road bike-sized bullhorn handlebars, and this would be essentially the same operation, made easier by the parallel flat sides of the shim.

If you employ anything as a wrap-shim, then the shifter will be centered on the 'bar, just as if you were to clamp it directly. However, if you wish to try --and if there is a rubber-supply store in your town -- I've had great luck making dense, non-slip shims from rubber/belting laminates. They come in differnet thicknesses to suit your needs. Just cut a section long enough to completely surround the bar when butted end-to-end, secure with a short piece of tape (to hold it temporarily in place), and then clamp whatever around it. The friction provided by the rubber means most clamped components (including road bike brake levers on MTB-diamater 'bars) need little clamping force to hold securely.

I hope you've solved the problem already, but these are the best suggestions I can offer at present.

Best,

Dan.

[triaesthete]

Hi Keleher
the internal diameter of the GB shifter is approx 29mm. If you were to enlarge the shim's inner radius to 26mm it would fit the sleeve on your bar, BUT 3mm is not sufficient clearance to run the brake cable through the centre of the shifter along with the handlebar.
This factor also precludes running the shifter directly adjacent to the stem clamp. (If it were this close the brake cable could not curve properly as it exits the inboard side of the shifter body.)

If you separate the brake cable from the bar outboard of the shifter it would then run in front of your fingers when operating the twistgrip.

In summary the shifter is just big enough for 24mm bar diameter with practical front brake cable run as well.

You could run the Thorn narrow centre bulge bars with a 0.6mm shim and get the GB shifter to within about 20mm of the clamp and maintain cable run, OR you could modify the shim and run retro style front brake levers with top exit cables! And doubtless more besides.

Good luck
Ian

[keleher]

In the end, I put a nitto noodle on and just used the grub screws to keep it in place. Works great.