Beginner Drivetrain Upgrade - help!

Discussion in 'Cycling Equipment' started by Jacobe Hazzard, May 13, 2003.

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  1. I am fixing up a cheap bike to ride, and this is the first time I have tried doing my own repairs. I
    could really use some advice about my drivetrain.

    Originally the bike had a Shimano SIS gripshift, but the right one wasn't working (jammed) so as a
    temporary measure I replaced it with a regular shifter, with a lever. Only problem, I have 6 rear
    sprockets and my new shifter in indexed for 7. Shifting is not great, and I'm not so optimistic that
    I could improve it much by adjusting the derailer. Maybe this isn't the case?

    My question is: Can I use any Shimano SIS shifter indexed for 6 sprockets, and have it be compatible
    with my derailer/freewheel? In other words, can I just buy a new (grip)shifter and have some
    confidence that it will work fine on my bike? How much should I expect to pay for a shifter?

    Or am I better off replacing the derailer and/or sprockets at the same time? I have no reason to
    believe the derailer needs replacing, but the sprockets look a little worn. I would ask at the bike
    shop but I think I already know what they'll say ;-)

    I think eventually I will want to upgrade the whole drivetrain, but if I could I would prefer to get
    the one I have now working at optimum and save the money.

    Thanks,

    Adam
     
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  2. Jacobe Hazzard wrote:
    > I am fixing up a cheap bike to ride, and this is the first time I have tried doing my own repairs.
    > I could really use some advice about my drivetrain.
    >
    > Originally the bike had a Shimano SIS gripshift, but the right one wasn't working (jammed) so as a
    > temporary measure I replaced it with a regular shifter, with a lever. Only problem, I have 6 rear
    > sprockets and my new shifter in indexed for 7. Shifting is not great, and I'm not so optimistic
    > that I could improve it much by adjusting the derailer. Maybe this isn't the case?
    >
    > My question is: Can I use any Shimano SIS shifter indexed for 6 sprockets, and have it be
    > compatible with my derailer/freewheel? In other words, can I just buy a new (grip)shifter and have
    > some confidence that it will work fine on my bike?

    Yes, that will work.

    > Or am I better off replacing the derailer and/or sprockets at the same time? I have no reason to
    > believe the derailer needs replacing, but the sprockets look a little worn. I would ask at the
    > bike shop but I think I already know what they'll say ;-)

    Yes and no. I would suggest going for a 7-speed freewheel, which will work fine with your 7-speed
    shifter. There is no need to replace the derailer for this, derailers don't care how many speeds.
    (When you see the phrase "[n]-speed derailer" you're looking at marketing hype, not a technical
    description.)

    > I think eventually I will want to upgrade the whole drivetrain, but if I could I would prefer to
    > get the one I have now working at optimum and save the money.

    You will need a new chain to go with the new freewheel.

    Sheldon "Upgrades" Brown +--------------------------------------------------------------+
    | If you don't like yourself, you _can't_ like other people | --Robert A. Heinlein |
    +--------------------------------------------------------------+ Harris Cyclery, West Newton,
    Massachusetts Phone 617-244-9772 FAX 617-244-1041 http://harriscyclery.com Hard-to-find parts
    shipped Worldwide http://captainbike.com http://sheldonbrown.com
     
  3. Sheldon Brown wrote:

    >> Or am I better off replacing the derailer and/or sprockets at the same time? I have no reason to
    >> believe the derailer needs replacing, but the sprockets look a little worn. I would ask at the
    >> bike shop but I think I already know what they'll say ;-)
    >
    > Yes and no. I would suggest going for a 7-speed freewheel, which will work fine with your 7-speed
    > shifter. There is no need to replace the derailer for this, derailers don't care how many speeds.
    > (When you see the phrase "[n]-speed derailer" you're looking at marketing hype, not a technical
    > description.)

    OK this sounds good. If I replace the freewheel and the chain, do I need to think about replacing
    the chainwheels as well, or do they wear more slowly?

    And BTW I love your website. 5 days ago I didn't know what a freewheel was!

    Adam
     
  4. Jacobe Hazzard wrote:

    >>>Or am I better off replacing the derailer and/or sprockets at the same time? I have no reason to
    >>>believe the derailer needs replacing, but the sprockets look a little worn. I would ask at the
    >>>bike shop but I think I already know what they'll say ;-)

    I replied:

    >>Yes and no. I would suggest going for a 7-speed freewheel, which will work fine with your 7-speed
    >>shifter. There is no need to replace the derailer for this, derailers don't care how many speeds.
    >>(When you see the phrase "[n]-speed derailer" you're looking at marketing hype, not a technical
    >>description.)
    >
    >
    > OK this sounds good. If I replace the freewheel and the chain, do I need to think about replacing
    > the chainwheels as well, or do they wear more slowly?

    Lower-end bikes have steel chainrings, which last almost forever.

    Sheldon "Steel Israel" Brown +------------------------------------------------------------+
    | A touchstone to determine the actual worth of an | "intellectual"--find out how he feels about
    | astrology. | --Robert A. Heinlein |
    +------------------------------------------------------------+ Harris Cyclery, West Newton,
    Massachusetts Phone 617-244-9772 FAX 617-244-1041 http://harriscyclery.com Hard-to-find parts
    shipped Worldwide http://captainbike.com http://sheldonbrown.com
     
  5. The spacing of a six speed cluster (the group of cogs) is different than a seven. The seven's being
    closer together. The two are not compatible, sorry. It may not look like much of a difference
    between cogs, but it adds up with each successive shift.

    My suggestion would be, if you can't find a six speed shifter, spring for a seven speed cogset. I
    believe Shimano still makes seven speed freewheels, Ask Sheldon, he'll know.

    May you have the wind at your back. And a really low gear for the hills! Chris

    Chris'Z Corner "The Website for the Common Bicyclist": http://www.geocities.com/czcorner
     
  6. Chris Zacho "The Wheelman" wrote:
    > The spacing of a six speed cluster (the group of cogs) is different than a seven. The seven's
    > being closer together. The two are not compatible, sorry. It may not look like much of a
    > difference between cogs, but it adds up with each successive shift.

    Hehe, this wasn't really my question. If you try to ride with this hardware you figure out pretty
    fast it's not compatible :) I was wondering about the best fix.

    > My suggestion would be, if you can't find a six speed shifter, spring for a seven speed cogset. I
    > believe Shimano still makes seven speed freewheels, Ask Sheldon, he'll know.

    This is what I plan on doing, thanks. And BTW I like your webpage, too. Especially the MacGyverisms.

    Adam
     
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