Old 09-29-21, 09:21 AM
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Join Date: Jul 2020
Location: Calgary, AB Canada
Posts: 220

Bikes: 1992 Miyata 1000, 1997 Trek 730, 2001 Airborne Zeppelin, 1980+ Nishiki Olympic

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70sSanO Thank you for your comments. I may wind up filing the boss covers as you suggest but have been reluctant to do that thus far for two reasons:

1) In another of my threads, someone mentioned that the covers are notorious for breaking when filed.

2) These shifters are pricey these days. After shipping, I'm looking at $150 CAD used or $350 CAD NOS. I'm not done searching for better deals though.

Studying the parts that I have on hand in greater detail, I may have some additional options that I hadn't considered:

3) Buy flat boss covers meant for a different downtube shifter model and use them with the 9 speed downtube shifters. As far as I can tell, the boss covers on my 7 sp downtube shifters are identical to the boss covers on my 9 speed bar ends other than the radiuses.

4) Use the boss covers from my 9 speed bar ends for the 9 speed downtube shifters.

Both of these strategies hinge upon the boss covers for different speed down tubes, and for bar ends, being interchangeable. And that I'm not sure about because, frankly, I don't yet know how these kinds of shifters do their indexing.

In the small parts diagram below, would you be able to tell me where the indexing happens? As in, which part determines the number of speeds? Does it happen within part #2? Part #2 keys into part #6 but I don't think that's actually where the action is. In the parts that I have available (7sp & 9 sp), the number of depressions in those parts always numbers six rather than the number of speeds.

Harold74 is offline