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  1. #1
    . bormoglot's Avatar
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    Convert/replace 105's 9spd 12-23 cassette to 12-28

    What is the most practical way to convert 105's 9spd 12-23 cassette to 9spd 12-28 or something like that?
    - One option is to buy Ultegra 12-27... Cost ~$50
    - Another one is to buy something like SRAM PG-950 11-32, take 24 and 28 sprockets and replace 16 and 23 sprockets on the 12-23... The issue here is that I am not sure that PG-950 can be taken apart... Cost ~$20
    - Anything else?

  2. #2
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    With individual cogs from Sheldon Brown you could probably build a 12-28 or 13-28 9-speed. Unless you have access to some useable cassette parts this would require buying at least two and more likely three cogs, and would probably cost as much or more than a new 9-speed 12-27. It would be easier if you were starting with a 12-25. I have converted a 12-25 to a 13-28 and 14-28.

    Al
    Last edited by Al1943; 04-24-07 at 04:30 PM.

  3. #3
    Gone, but not forgotten Sheldon Brown's Avatar
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    Quote Originally Posted by bormoglot
    What is the most practical way to convert 105's 9spd 12-23 cassette to 9spd 12-28 or something like that?
    - One option is to buy Ultegra 12-27... Cost ~$50
    - Another one is to buy something like SRAM PG-950 11-32, take 24 and 28 sprockets and replace 16 and 23 sprockets on the 12-23... The issue here is that I am not sure that PG-950 can be taken apart... Cost ~$20
    I made a similar setup when I put my Hetchins together, starting with a 12-23, I removed the 16 and added a 28 on the bottom.

    http://sheldonbrown.org/hetchins/

    If memory serves, the stock 16 was rivetted to the 17, so I just took a 17 from stock to replace the pair.

    However if I didn't have a 17 on hand I could have just drilled out the rivets and removed the 16. These sprockets engaged the Freehub body splines directly, they were not on a spider module as the three bottom sprockets are.

    Sheldon "Magnum Opus" Brown
    [COLOR=blue][CENTER][b]Harris Cyclery, West Newton, Massachusetts[/b]
    Phone 617-244-9772, FAX 617-244-1041
    [URL= http://harriscyclery.com] http://harriscyclery.com[/URL]
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  4. #4
    . bormoglot's Avatar
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    Thanks, I've just did it using SRAM-950 11-32. One very nice local mechanic helped me.
    1) It turned out that there is just one easily removable rivet that holds 2005 105 9spd 12-23 cassette.
    2) Rivets that hold together SRAM-950 11-32 are easily removable as well, no drilling required in both cases.
    3) We've removed 16 and 23 and added 24 and 28
    4) 105's short cage rear derailler handles it well, I didn't even need to change chain length.

  5. #5
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    Shifting?

    How does the shifting work going from the 105 cog to the Sram cog?

  6. #6
    Senior Member capwater's Avatar
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    Quote Originally Posted by bw77
    How does the shifting work going from the 105 cog to the Sram cog?
    Should be no problem; Shimano 8 SRAM are compatible. Easier way would be to just grab an Ultegra 12-27. You could get an SRAM 12-26, pull out the 13 and slap on a 28 from a mtb cassette on the ass end. Depending on how much work you want to do, how much money you want to spend and how many extra parts you already have a round. Built me a schweet 13-28 that way, but again I already had the cogs laying around.

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    ThreadKiller Evoracer's Avatar
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    Quote Originally Posted by bw77
    How does the shifting work going from the 105 cog to the Sram cog?
    I have found that the SRAM cassettes shift better than my Ultegra 12-27.

    Miche makes & sells individual cogs and spacers and can be mixed and matched as you please with your current cassette. I pulled the 14t and added a 29t to the back side of the spider hub'd cogs on the Ultegra cassette. Works great with the std cage Ultegra derailleur as well.

  8. #8
    . bormoglot's Avatar
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    Quote Originally Posted by bw77
    How does the shifting work going from the 105 cog to the Sram cog?
    During my small test ride around the block, I haven't noticed any problem with shifting, even though I was expecting rough shifts at 15<->17 and 21<->24 because we've disrupted natural Hyperglide alignment.

    However, I haven't tried to switch it under the load (like going uphill) yet.

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