Overcomplicated Suicide Shifters



Jun 13, 2015
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I thought I'd do a quick post about the Retro Rocket's shifters as, though I doubt this is likely to be imitated, there may be some helpful things for anyone contemplating a suicide shifter from grip shifters for the first time.

This is Retro Rocket:

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The challenge here was fitting everything into the hollow rocket body while also allowing the rocket body to be raised and lowered. Oh, and having everything actually work properly.

The rocket fuselage is HDPE drain pipe and this bike has been used pretty often over the last several years, hence the "patina" of chipped paint. Anyway, these are the original ~1997 lower end Shimano grip shifters mounted to a piece of cut handlebar that spans across the fuselage. Normally, the grip mechanism is held together by the grip on one end and the allen set screw on the main casing of the shifter. This could have been solved more easily than what follows, but I also had the switches for the lights in the ends of the wood shift levers (originals were damaged in a fall and the switches were redundant, anyway, so now they're just switched via the switches on the 12V battery packs instead) and this required the shift lever shafts to be tubes to wire up the switches. The smallest suitable tube I could use was 3/8" OD, so I got 1/2" shaft collars and drilled holes in them for the tube to pass through. Whatever part of the grip shifter extended beyond the collars, I cut off. I couldn't run the wires through the handlebar and up the shift tubes for the sake of safety (sharp edges with such thin wall even if filed), strength, and there wasn't space with the tensioning mechanism, so they passed through the bottom of the tube into the rocket body with an extension spring transitioning the wires from rotating shifter to stationary rocket body.
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Here, you can see the extension spring the wires used to travel through. In the middle of the handlebar, you can see the top of a lightly rusting thumbscrew that I drilled a hole through the head of for the shift tube to pass through. This is the end of the tensioner that works to both hold the shifter assembly together in lieu of the grip it was originally designed for and pull the whole thing in toward the rocket fuselage with adjustable tension so that ghost shifts can be adjusted out (mostly, but I think the little that remains is a consequence of the convoluted turns the shift cable housing has to make within the rocket fuselage).
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Here are the tensioners (each shifter has its own). The thumb screw is the threaded part you can see inside the cut handlebar. There is a nylok nut on it that is seated against a sealed ball bearing (to allow the shifter to turn) which is, in turn, seated against a flat aluminum insert. Turning the nylok nut adjust the tension by pulling the shift lever in against the resistance of the bearing on the fixed aluminum insert. The vertically threaded thing in the middle with the wing nuts is just a stopper that adjusts the angle of the nose of the rocket, which is needed to match the height of the seat, which the other end of the rocket fuselage is secured to, so you can ignore that. You can also see some of the convoluted cable housing I was writing about.
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Just another angle where the bearing and aluminum insert is more visible.

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Hope this makes sense and is helpful to someone for whatever ideas they might be contemplating.
 

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