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PostPosted: Wed Oct 02, 2013 8:26 pm 
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lurkin' kitty

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Shimano's clutch rear derailleurs are very good at dealing with chain-slap. Unfortunately Shimano went to a different pull ratio with the 10sp gear. A few people have modified 10sp rear derailleurs to work with 8/9sp shifters by changing where the cable attaches to the derailleur, effectively changing the ratio.

The first time I saw the mod was from this german site:
http://www.mtb-news.de/news/2012/11/14/ ... tenglueck/

One of the smarter things he did was to build some adjustably into the modification where turning the threaded insert changes the cable's "attachment" point.
Image

I want to try to do this. I won't have a problem drilling and tapping the larger hole with my simple garage tools, but I don't have the ability to drill the off-center hole on the insert...really don't have a way to create the insert at all. Does anyone have a suggestion of something off the shelf I could use for the insert?


Thanks,


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PostPosted: Wed Oct 02, 2013 9:10 pm 
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pussy
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Shimano 10sp RD + SRAM 9sp shifter = no modifications necessary.


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PostPosted: Wed Oct 02, 2013 9:20 pm 
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big hucker
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ohpossum, welcome!

I ran that page through google translate and thought it was a good read. Here's the pic that helped me better understand the cable routing.

Image

I didn't see a photo that described the insert. Can you elaborate on that part?

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PostPosted: Thu Oct 03, 2013 5:16 pm 
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lurkin' kitty

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Sti wrote:
Shimano 10sp RD + SRAM 9sp shifter = no modifications necessary.


What if I want to run 8sp? ;)


marpilli wrote:
ohpossum, welcome!

I ran that page through google translate and thought it was a good read. Here's the pic that helped me better understand the cable routing.


I didn't see a photo that described the insert. Can you elaborate on that part?


Thanks for the warm welcome. Your post on the other forum about the DIY bushing tool is what brought me here.

By changing the derailleur cable's attachment point you change the length of the lever between the attachment point and the derailleur's pivot. Changing that lever length changes the amount the derailleur moves with each pull of the cable from the shifter. Zee German figured out where the new attachment point needed to be, but you need some adjustibilty built in to the system to minutely change the length of the lever to tune it. Typical garage tools aren't going to give the precision needed to drill the hole exactly where it needs to be. The insert solves that problem very well..

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In a perfect world you could drill a small hole in the derailleur at the perfect spot that would make the insert unnecessary, but I definitely don't have that level of expertise or the right tools to pull that off. I've read that zee German is offering to modify new derailleurs for a small fee, but it gets costly quick when you factor the international shipping to/from the US to Germany. Besides, it looks like a fun project to attempt on my own with hopefully some help from the HK experts.


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PostPosted: Thu Oct 03, 2013 6:14 pm 
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bad kitty!
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I assume you have a M6 tap.
Take a piece of steel, and make a M6 in it.
Cut a piece of M6 bolt in the needed length, make a slot in it for a screwdriver, and mount it in the piece of steel you just made, securing it with blue Loctite. Let it cure for like an hour.
Make a dot in the bolt where you want the hole. Make sure it does not collide with the slot you cut in it earlier.
Use a drill press to drill the hole.
Put the whole shebang in an oven at 250C for like half an hour, to break down the Loctite, and unscrew your bolt from the steel piece.

Presto! You got an off center drilled M6, made with pretty much kitchen table technology.

Magura :)

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PostPosted: Fri Oct 04, 2013 1:33 am 
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big hucker
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ohpossum, thank you. That description makes sense, also. I didn't notice that offset hole was part of a bolt shaft.

Magura, very clever! In theory he could use whatever type of matching tap/bolt he has available (within reason, of course).

I'm tempted to give it a try and I don't even need it. :lol:

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PostPosted: Fri Oct 04, 2013 8:38 am 
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bad kitty!
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marpilli wrote:
ohpossum,
Magura, very clever! In theory he could use whatever type of matching tap/bolt he has available (within reason, of course).



It has to be a relatively fine pitch bolt, thus I wrote M6, as the imperial bolts that are around the same diameter, has bigger pitch.
If the pitch becomes too high, you will add another variable to the mix, which I'm not sure is going to make adjustment any easier.

The ideal solution would be to not thread the hole in the derailleur, and fix the insert in place with a half height nut on each side. That would make it true 2D adjustment.


Magura :)

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