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Old 08-05-22, 09:08 PM
Andrew R Stewart 
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Bikes: Stewart S&S coupled sport tourer, Stewart Sunday light, Stewart Commuting, Stewart Touring, Co Motion Tandem, Stewart 3-Spd, Stewart Track, Fuji Finest, Mongoose Tomac ATB, GT Bravado ATB, JCP Folder, Srewart 650B ATB

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Measuring 9 Speed Movements

This thread is already many years old and others have gone before me here. I have run mixed drivetrains since the mid 1990s and don't want to move on from my many Campy Ergo (second gen pointy hood versions) levers. But stuff changes over the market cycles of nearly 30 years. It's too bad Campy didn't offer big cog compatible rear ders when it was about 9 or 10 speeds back there. I've thought about this for way too many hours while riding and decided to start some real research in cable pull ratios, guide pulley lateral movement per click and how "incompatible" choices can be made to work. I've been running JTek ShiftMates to translate between Shimano and Campy parts of the system for years too.

With the foundation of actual measuring beats reading I finally decided to make some shifter cable pull and resulting der cage lateral travel measurements and do so with some ease of repeating values and swapping out parts. A fixture was called for. Here's what i came up with.

I've had three different configurations measured and am beginning to see some trends. My measuring technique needs better consistency, Shimano seems to have a narrower range of high and low measurements in general and just because you can read off a scale a thousandth of an inch doesn't mean much in real life drivetrain performance.

The lever's cable pull differences per click for campy averaged nearly twice what the Shimano lever did. And as I expected the cage travel per click was better "controlled" on the Shimano system. No surprises here although I wish the Campy system scored better as I really like the fixed (WRT to shifting) brake lever blade design.

The test rig I did does mimic real bikes largely. I would make a shift to a lower gear at the lever, recycle back down a gear and return to that first shift again then pluck the cable mid point to try to settle all in better before measuring. Friction does seem to make those thousandths of an inch stand out. But the clicks points, and the lever cable travel for each, compared to what the cage was traveling didn't always seem to match up as I thought it would. I blame cable friction here, just like in real life

What do I do next? test more combos I have on hand and include the mixed systems that use a ShiftMate. Refine my technique. Think about lowering the cable friction (in these tests the cable was dry and all sliding contacts were in a liner or casing).

I'll continue exploring with the stuff I have on hand and report back with more info as I find it worthwhile. Andy
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