Old 05-10-17 | 10:55 PM
  #15  
cpach
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Joined: Oct 2009
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From: Mt Shasta, CA, USA

Bikes: Too many. Giant Trance X 29, Surly Midnight Special get the most time.

Originally Posted by Darth Lefty
Here's a thing I wrote about why I suspect the Shimano and Campy 11 are closer than websites like your link report: http://www.bikeforums.net/19060234-post11.html I just wish I had the parts and time to try it!

First, I take the tables as source material, because I know there was no grand original project, it's just an accumulation... so there are some accumulated errors from people copying and pasting them for years, without supporting data and rounding off the third digit. You still sometimes see different ratios listed for Shimano 10 and 11 mountain derailleurs which was based on an erroneous early report that Shimano 11 MTB would have the same cog spacing as 10, which I think sprang from the fact it still went on 8-9-10 freehubs; instead it turned out to be the same as all the other 11's, and the derailleur parallelogram is identical. It's pretty rare that you see original source measurements of cable pull, except hearing from someone that it worked or didn't.

Second, there's also the problem that a shift-per-click isn't always perfect for a Shimergo setup because it doesn't use the last two stops, throwing off the average. But the average is sometimes all you get because the first person who got it to work just measured the distance between the stop and the pinch bolt in first and 11th. I have a Shimergo 9-11 setup and it works even though the table says it's off, because the lower shifts are bigger.

And finally, the spacing only needs to work pretty close for 3 or 4 clicks on either side of whatever you set as perfect. The top position is big and sloppy so the RD position can be set by the limit screw. Some slop is allowed by the Centeron pulley, and that gives you some leeway to set it perfectly in 4th-5th and still be close enough at 1st and 8th. So, if it doesn't work the 9 SIS, it would probably work the 8 and that would still be good to know. And what do the 4700 shifters do?
Were I you I'd go the 10sp Dynasys option--my experience is that it is far more robust and fault tolerant. Additionally, if you want a mountain sized cassette (40t big cog) I'd go 11sp, as 11sp Shimano mountain basically dishes the big cog inboard to fit on a 10sp freehub.
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