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  1. #1
    Formerly Carlos9
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    smaller rear or larger front...

    so when it comes time to change the gearing, prices aside, is it better/easier to change to a smaller rear cog or a larger chainring. does it really make any difference?

    also, obviously the chain will need to be shortened/lengthened depending on which way i go. assuming i might want to change back to the original gearing, can i add/subtract links or should i get a chain for each?

    thanks.

  2. #2
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    Changing the chain ring is the way to go. Generally, subtracting one tooth from the cog will yield the same amount of change in gearing as adding three to the front; so you get more incremental change from changing out the chain ring. Also, it's cheaper.

    You can add/ remove links with a chain tool. It's not hard at all, just don't push the pin all the way out of the chain. It's a weird process to try and describe in words without a visual. I'm sure there is video instruction on the internet somewhere though. As for a tool, get something along the lines of the Park Tool Master Chain Tool or the Pedros Pro Chain Tool.

  3. #3
    Formerly Carlos9
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    Quote Originally Posted by monzie
    Changing the chain ring is the way to go. Generally, subtracting one tooth from the cog will yield the same amount of change in gearing as adding three to the front; so you get more incremental change from changing out the chain ring. Also, it's cheaper.

    You can add/ remove links with a chain tool. It's not hard at all, just don't push the pin all the way out of the chain. It's a weird process to try and describe in words without a visual. I'm sure there is video instruction on the internet somewhere though. As for a tool, get something along the lines of the Park Tool Master Chain Tool or the Pedros Pro Chain Tool.
    great advice, thanks.

    i have the tools needed, etc and have worked on chains before so it looks like i'm good to go

  4. #4
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    I've normally changed out the rear cog, to me it's easier than removing the crank arm and 5 crank bolts and reassembling. Also, the cogs I've purchased were most always less expensive than a chainring....

  5. #5
    Formerly Carlos9
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    Quote Originally Posted by Just1Gear
    I've normally changed out the rear cog, to me it's easier than removing the crank arm and 5 crank bolts and reassembling. Also, the cogs I've purchased were most always less expensive than a chainring....
    thats a good point.

  6. #6
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    Quote Originally Posted by Just1Gear
    I've normally changed out the rear cog, to me it's easier than removing the crank arm and 5 crank bolts and reassembling. Also, the cogs I've purchased were most always less expensive than a chainring....
    Agreed. I find it much faster to swap out the rear cog. Plus, I can use the same chain length across 3 cogs (16, 17, 18), so I don't have to break the chain.

    When I'm forced to change my chainring (due to wear), I don't have to remove the crank arm. Not sure why Just1Gear has that problem. I'm also running a 5-bolt, 94bcd spider, ring in the middle position.
    Last edited by amishscum; 04-27-2011 at 10:43 AM.
    "I like skinny jeans. Sometimes I wear them to the mall to get an Orange Julius." -Chim Chim

  7. #7
    Formerly Carlos9
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    Quote Originally Posted by amishscum
    Agreed. I find it much faster to swap out the rear cog. Plus, I can use the same chain length across 3 cogs (16, 17, 18), so I don't have to break the chain.

    When I'm forced to change my chainring (due to wear), I don't have to remove the crank arm. Not sure why Just1Gear has that problem. I'm also running a 5-bolt, 94bcd spider, ring in the middle position.
    are you using a tensioner that allows you to use the same chain?

  8. #8
    The need for singlespeed
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    Quote Originally Posted by monzie
    Generally, subtracting one tooth from the cog will yield the same amount of change in gearing as adding three to the front;
    only on your 48/16 track bike

  9. #9
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    Quote Originally Posted by carlos9
    are you using a tensioner that allows you to use the same chain?
    Nope. Sliding dropouts. Actually, mine are called "rocker" dropouts, but it's the same concept.
    "I like skinny jeans. Sometimes I wear them to the mall to get an Orange Julius." -Chim Chim

  10. #10
    Formerly Carlos9
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    Quote Originally Posted by amishscum
    Nope. Sliding dropouts. Actually, mine are called "rocker" dropouts, but it's the same concept.
    ahhh. yeah, unfortunately i have vertical dropouts and got lucky off the bat with finding the magic chain length for my first gearing set up. i'd really like to avoid a tensioner if possible, which was why i mentioned shortening and lengthening the chain...

  11. #11
    nothing to see here
    Reputation: Stevob's Avatar
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    What is your current gearing?
    I see hills.

    I want to climb them.

  12. #12
    Formerly Carlos9
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    Quote Originally Posted by Stevob
    What is your current gearing?
    32x20

  13. #13
    nothing to see here
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    32x18 might work and depends on how tight your current chain is, but you'd need to take a full link out and add a half link.

    Do you know your chainstay length? If not what frame/year is it?
    I see hills.

    I want to climb them.

  14. #14
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    I have always swapped out rear cogs to figure out my gearing. I bought a pack of super cheap sprockets of different sizes and I also took apart an old cassette that had indivdual cogs rivited together. Once I found the gearing I liked I bought a nice single speed cog. It was the cheapest and easiest way to find the right gearing.

    But I used a chain tensioner. I was at a magic gear but didn't trust it as if the chain stretched I would need a tensioner. And even with half links I think if you had a magic gear and tried to go down one or up one tooth you would loose the magic gear. One chain link is about 1" and a half of chain is 1/2". So if your gear change isn't exactly in 1/2" (half link) or 1" if using full links then you will loose your magic gear.

  15. #15
    Formerly Carlos9
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    Quote Originally Posted by Stevob
    32x18 might work and depends on how tight your current chain is, but you'd need to take a full link out and add a half link.

    Do you know your chainstay length? If not what frame/year is it?

    the chain is perfect right now, probably less than 1/4 inch of play. i already have a half link in there, so i guess i could just take it out?

    its a '93 marin bear valley. no idea on the chainstay length...

    is there a "formula" where 1 tooth [either front or rear] = a certain change in chain length?

  16. #16
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    It's a little bit of a grey area, but for each increment in teeth, the chainlength changes by approximately 1/4 of a link (remember that one full link = 1"), and that is then split in half again to determine chainstay length. So one tooth = approximately 1/8" alteration to chainstay length.

    So if you increase the overall tooth count front and rear by 4 teeth, you'll need to add one full link. But there's a bit more complex geometry to consider than just that.

    Have a play around with this link.

    Google was not my friend in finding out the chainstay length on your frame.

    Someone please correct me if I'm wrong.
    I see hills.

    I want to climb them.

  17. #17
    Formerly Carlos9
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    Quote Originally Posted by Stevob
    It's a little bit of a grey area, but for each increment in teeth, the chainlength changes by approximately 1/4 of a link (remember that one full link = 1"), and that is then split in half again to determine chainstay length. So one tooth = approximately 1/8" alteration to chainstay length.

    So if you increase the overall tooth count front and rear by 4 teeth, you'll need to add one full link. But there's a bit more complex geometry to consider than just that.

    Have a play around with this link.

    Google was not my friend in finding out the chainstay length on your frame.

    Someone please correct me if I'm wrong.

    thats all helpful info, thanks again. i couldn't find the chainstay length either. i'll probably end up just messing around with it and see what happens.

  18. #18
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    Keep in mind when switching things around that smaller cogs will wear faster and increase the possibility of chain skippage. However, this would more likely occur when you get into cogs with less than 16 teeth...uncommon in mtbing I suppose.

  19. #19
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    Quote Originally Posted by amishscum
    When I'm forced to change my chainring (due to wear), I don't have to remove the crank arm. Not sure why Just1Gear has that problem. I'm also running a 5-bolt, 94bcd spider, ring in the middle position.
    Hmmm, I guess your right, I don't HAVE to remove the crank arm.....I guess the times I've changed the chainring I've already had the arm off for something else anyway.

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