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  1. #1
    rugged individualist wphamilton's Avatar
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    Shimano 2300 RD vs granny cog

    Will it work? I've cast about and I think it could, but I don't have a definite answer. I've never been steered wrong here so please indulge me again.

    I have a Shimano 2300 Rear Derailleur, a single 44T front ring, and a Shimano Hyperglide 8-speed cassette with 7 cogs 11-28, with 8-speed downtube shifter. I want to use 8 cogs up to 30T or 32T.

    I found a RD 2300 spec sheet which says:

    Total capacity 35 teeth or less
    Largest sprocket 26T
    Smallest sprocket 11T
    Front chainwheel tooth difference 22T


    Total capacity I take to mean the number of teeth difference between large-large and small-small so I'm way under that, and with just one ring the last one is irrelevant (right?). But what about "largest sprocket"? It's working fine as is with a 28T sprocket. Can that be stretched to 30? 32?

  2. #2
    Low car diet JiveTurkey's Avatar
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    You might be able to ge away with 30T or 32T largest cog.

    Using a single chainring is in your favor. When I've exceeded the largest cog rating, bumping had occurred in small/big, but not middle/big.

    Keep the chain on the shorter side of the potential range (try Sheldon's big/big + 1" method) and flip around the RD's b-tension screw so that its head butts up against the RD hanger.
    Quote Originally Posted by slopvehicle View Post
    Not wearing a helmet makes me more aware of my surroundings. I find myself anticipating the hardness of concrete 50 or 100 feet in front of me, it's almost a zen-like connection between my face and the pavement.

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    The only way to be sure is to try it and see, but just because you are getting away with 2 teeth bigger than the rated sprocket size does not mean that you will get away with 6.

  4. #4
    rugged individualist wphamilton's Avatar
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    Since it's questionable, if it were you would you risk 8 or 10 dollars for a sprocket and an hour of messing with to find out? Given that it's a "like to have" instead of "really need", and the chain angle for the additional gear is also going to be a little "iffy".

  5. #5
    Low car diet JiveTurkey's Avatar
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    So, you're using just 7 cogs of an 8-speed cassette? Is there a spacer behind the largest cog? I'm making sure you have an 8-speed-plus freehub and not a 7-speed-or-less freehub.
    Quote Originally Posted by slopvehicle View Post
    Not wearing a helmet makes me more aware of my surroundings. I find myself anticipating the hardness of concrete 50 or 100 feet in front of me, it's almost a zen-like connection between my face and the pavement.

  6. #6
    rugged individualist wphamilton's Avatar
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    Yes, all it would take is removing the spacer and putting a sprocket in, a longer chain and adjusting the rear derailleur.

  7. #7
    Senior Member himespau's Avatar
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    Heck if you remove the spacer and put in the larger cog, you're not out much if it doesn't work, right? I mean in essence you'll be where you are now but with a non-functional 8th cog instead of a spacer.
    Punctuation is important. It's the difference between "I helped my uncle, Jack, off a horse" and "I helped my uncle Jack off a horse"


  8. #8
    rugged individualist wphamilton's Avatar
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    I'm resurrecting this old thread to report how it turned out. (Don't you hate it when you search a question, find a discussion for it, and there's no resolution?)

    I had put this off until I wanted to get a spare rear wheel, to do both at once. For some reason I went with an SRAM 830, 11-30, instead of a Shimano Hyperglide. In short, the 2300 Rear Derailleur handles a 30 tooth sprocket like a champ! I didn't lengthen the chain, which I think was a half link long to begin with.

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