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  1. #1
    Senior Member Dave1899's Avatar
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    18 tooth cog for a Raleigh Twenty

    Where can I get an 18 tooth cog to fit my SA 3spd hub and do I need any special tools to change it out? Also, would I need to add any links to the chain?
    See ya on the trail,
    David

  2. #2
    Bicycle Repair Man !!! Sixty Fiver's Avatar
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    SA still makes new cogs in a wide range of sizes and you can order one of those or if you have a bike co-op you might find one there... the stock cog is a 15 so you will need a longer chain and the chain length and dropout design on the Twenty really works better with an even / odd combination.

    The dropout is short and is angled upwards so there is not a lot of room to play with chain tension... a 17 or 19 would be an easier switch.

  3. #3
    tcs
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    Quote Originally Posted by Sixty Fiver View Post
    SA still makes new cogs...
    ...and in fact S-A cogs for their 2-3-4-5&7 speed hubs are interchangeable with Shimano cogs for their 3-4-7&8 speed hubs which are interchangeable with SRAM (F&S) cogs for their 2-3-5&7 speed hubs which are interchangeable with the cogs for many single-speed coaster brake hubs. These cogs have been an industry standard for some 60 years. You pop the retaining ring off with a flat blade screwdriver to change 'em out.

    ...and dropout design on the Twenty really works better with an even / odd combination. The dropout is short and is angled upwards so there is not a lot of room to play with chain tension... a 17 or 19 would be an easier switch.
    If an 18 will give you your most optimum gearing, use a half link.

    HTH,
    tcs
    "When man first set woman on two wheels with a pair of pedals, did he know, I wonder, that he had rent the veil of the harem in twain? A woman on a bicycle has all the world before her where to choose; she can go where she will, no man hindering." The Typewriter Girl, 1899.

    "Every so often a bird gets up and flies some place it's drawn to. I don't suppose it could tell you why, but it does it anyway." Ian Hibell, 1934-2008

  4. #4
    Senior Member November's Avatar
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    I put a 19 on mine and had to use a half-link.

  5. #5
    Senior Member Dave1899's Avatar
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    Quote Originally Posted by November View Post
    I put a 19 on mine and had to use a half-link.
    How'd that 19 work for you?
    See ya on the trail,
    David

  6. #6
    Senior Member November's Avatar
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    It works just fine. I leave it in 2nd gear for pootling along the MUP and it's perfect for that. In general I like my bikes geared towards the low end as I'm not a speed demon.

  7. #7
    Bicycle Repair Man !!! Sixty Fiver's Avatar
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    There is some variation in chain stay lengths between different 20's... this will effect how certain chain ring and cog combinations work.

  8. #8
    Senior Member Russcoles11's Avatar
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