Upgrade Shimano 105 Rear Cassette

Discussion in 'Cycling Equipment' started by Doug Dempster, Jan 22, 2003.

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  1. I'm in the process of upgrading my Shimano 105 rear cassette to add some more gear inches. The
    original was a 12-24, and I purchased a new 13-34 (as well as a new chain). I also converted from
    Ultraglide to Hyperglide. Despite my attempts to get everything adjusted, I can't shift to the 34
    ring, and the overall shifting is not clean. Will a longer chain cage help this? Am I just trying to
    add too many gear inches?

    Thanks for any advice.
     
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  2. If you originally had a standard-cage '105 rear derailleur, you're *way* beyond its capabilities
    (trying to get it to shift onto a 34t). Even a long-cage '105 will usually have trouble with that,
    dependent upon the position of the derailleur hanger.

    If you've got a standard-cage derailleur (which is likely, given the gear range of the original
    cassette), I'd drop by your LBS and pick up a good-but-inexpensive LX rear derailleur and everything
    should work just fine.

    --Mike-- Chain Reaction Bicycles http://www.ChainReactionBicycles.com

    "Doug Dempster" <[email protected]> wrote in message
    news:[email protected]...
    > I'm in the process of upgrading my Shimano 105 rear cassette to add some more gear inches. The
    > original was a 12-24, and I purchased a new 13-34 (as well as a new chain). I also converted from
    > Ultraglide to Hyperglide. Despite my attempts to get everything adjusted, I can't shift to the 34
    > ring, and the overall shifting is not clean. Will a longer chain cage help this? Am I just trying
    > to add too many gear inches?
    >
    > Thanks for any advice.
     
  3. Mark Boyd

    Mark Boyd Guest

    On Sun, 19 Jan 2003, Doug Dempster wrote:

    > I'm in the process of upgrading my Shimano 105 rear cassette to add some more gear inches. The
    > original was a 12-24, and I purchased a new 13-34 (as well as a new chain). I also converted from
    > Ultraglide to Hyperglide. Despite my attempts to get everything adjusted, I can't shift to the 34
    > ring, and the overall shifting is not clean. Will a longer chain cage help this? Am I just trying
    > to add too many gear inches?

    You need a rear derailleur that will handle a cog that large. Shimano road deraileurs won't do that,
    they are rated for 27 tooth biggest cog. I put an 11-30 cassette on a friends road bike and, with
    the B screw all the way in, it shifts fine but the derailleur bumps into the cog a little bit on the
    30. I'd expect the same problem using a Shimano MTB derailleurs, rated for 32 teeth, with a 34, but
    I haven't tried it. Shimano Mega-range derailleurs are rated for 34 tooth biggest cogs and would be
    the best solution for you.

    It isn't a big deal to switch the rear derailleur since, unlike Shimano front derailleurs, all of
    their rear derailleurs use the same amount of cable pull per cog. That means a Mega-range rear
    derailleur will work with your 105 shifters.

    Mark <http://www.cs.unca.edu/~boyd/bicycling.html
     
  4. Grenouil

    Grenouil Guest

    "Doug Dempster" <[email protected]> wrote in message
    news:[email protected]...
    > I'm in the process of upgrading my Shimano 105 rear cassette to add some more gear inches. The
    > original was a 12-24, and I purchased a new 13-34 (as well as a new chain). I also converted from
    > Ultraglide to Hyperglide. Despite my attempts to get everything adjusted, I can't shift to the 34
    > ring, and the overall shifting is not clean. Will a longer chain cage help this? Am I just trying
    > to add too many gear inches?
    >
    > Thanks for any advice.
    >

    FWIW - you might want to try a smaller set of chainrings rather than bigger rear sprockets. That way
    you can keep some fairly close ratios instead of having to spread the cogs to accommodate a 13 to 34
    range. I've switched both of my wife's bikes to 46-36-26 compact cranksets, with 12-24 or 12-25 at
    the back - works really well.
     
  5. Ronald

    Ronald Guest

    > FWIW - you might want to try a smaller set of chainrings rather than
    bigger
    > rear sprockets. That way you can keep some fairly close ratios instead of having to spread the
    > cogs to accommodate a 13 to 34 range.

    Yes, and smaller fronts also decreases the gaps in ratio between the existing cogs. Smaller fronts =
    closer gears, i always get the smallest chainrings possible for the required max. speed/cadence.

    "Grenouil" <[email protected]> wrote in message news:[email protected]...
    > "Doug Dempster" <[email protected]> wrote in message
    > news:[email protected]...
    > > I'm in the process of upgrading my Shimano 105 rear cassette to add some more gear inches. The
    > > original was a 12-24, and I purchased a new 13-34 (as well as a new chain). I also converted
    > > from Ultraglide to Hyperglide. Despite my attempts to get everything adjusted, I can't shift to
    > > the 34 ring, and the overall shifting is not clean. Will a longer chain cage help this? Am I
    > > just trying to add too many gear inches?
    > >
    > > Thanks for any advice.
    > >
    >
    > FWIW - you might want to try a smaller set of chainrings rather than
    bigger
    > rear sprockets. That way you can keep some fairly close ratios instead of having to spread the
    > cogs to accommodate a 13 to 34 range. I've switched both of my wife's bikes to 46-36-26 compact
    > cranksets, with 12-24 or 12-25 at the back - works really well.
     
  6. This sounds like it might be a good option. From reading some other threads, converting to a triple
    in front sounds fairly straightforward/relatively inexpensive. It appears that I might be able to
    keep my front derailleur, has anybody upgraded their front 105 to a triple and been able to do that?

    DGD

    "Grenouil" <[email protected]> wrote in message
    > >
    >
    > FWIW - you might want to try a smaller set of chainrings rather than bigger rear sprockets. That
    > way you can keep some fairly close ratios instead of having to spread the cogs to accommodate a 13
    > to 34 range. I've switched both of my wife's bikes to 46-36-26 compact cranksets, with 12-24 or
    > 12-25 at the back - works really well.
     
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