Joined: Feb 2012
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From: Rochester, NY
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, Stewart 650B ATB
Originally Posted by
CaptainPlanet
That's what I was thinking too when I wrote that message.
can you actually take out the 7th gear in an 8 speed cassette and turn it into a 7 speed cassette? Or would the cassette not work because the spacing issue or the flow is not continuous anymore? Sure, sometimes it means grinding off the assembly rivets or unthreading the bolt that can hole some cassettes together. But as long as you're going to that trouble why not also swap out the narrower 8 cog spacers for those from the 7 cog cassette The Shimano Mega Range cog sets have a huge tooth count difference from the second largest cog to the latgest one. Shifting is a tad rougher then the closer tooth count jumps elsewhere on the same cassette but can work.
the derailleur has no problem reading the largest gear on its own. To attempt 1~7, the h screw was all the way in and the l screw was falling out of the socket, but the shifter still can't make it go to big gear consistently. So I had to give up on that.
Not all Shimano ders are intended to swing the amount needed OR maintain the pulley travel amount per lever click across 8 cogs. This and the slop that can work into used lower end ders (pulley bushing, der parallelogram link pivots and B and cage pivots) can mean the system is not optimal at it's extreme.
And then there's what I mentioned before. That the 7 cog indexing spec is different from the 8 cog one. Shimano never intended the two cog counts indexing to be interchangeable. Shimano use to claim reverse compatibility for ders but not forwards. So an 8 speed rear der should work with a 7 cog lever and cassette but a 7 cog der won't with an 8 cassette and lever. The mix match will shift for a few cogs just fine before the .2mm cog C-C spacing difference adds up and the upper pulley won't be under that next cog with the next shift. Andy
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AndrewRStewart