Does this make sense ...

Discussion in 'Cycling Equipment' started by Appkiller, Sep 3, 2003.

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  1. Appkiller

    Appkiller Guest

    or am I confused? Can I take a 53/39 crank + 13-26 cassette with small cage rear der and slap a 50
    big ring and a 13-29 cassette on and expect it to not explode the rear der (if you haven't figured
    it out already, I am running Campy)?

    The max tooth difference span is the same, i.e.(assumes use of cross-chain),

    39 - 26 = 13 53 - 13 = 40

    40 - 13 = 27 Teeth difference between min and max cage excursion, the "amount of slack" that the der
    needs to pick up between min and max cage excursion.

    50 - 13 = 37 39 - 29 = 10

    37 - 10 = 27 Teeth difference.

    More than just wondering. I only use the 15, 14, 13 cogs with the 53 about once per year and
    probably wouldn't miss them.

    App
     
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  2. On Wed, 03 Sep 2003 12:13:56 +0000, Appkiller wrote:

    > or am I confused? Can I take a 53/39 crank + 13-26 cassette with small cage rear der and slap a 50
    > big ring and a 13-29 cassette on and expect it to not explode the rear der (if you haven't figured
    > it out already, I am running Campy)?

    Well, the amount of slack you need to take up will be the same, so that is fine. My only question
    would be the max sprocket size for the rear derailleur, which for most Campy short & med cage
    derailleurs is 26 IIRC. You may have trouble with the jockey wheel riding on that 29, which gives a
    weird vibration to the bike, and does not shift well. If you can clear it, then it will be OK.

    Another option, since what you want really are lower gears, is to get a smaller inner ring as well
    as outer ring, and keep the cassette as it is. Of course, that means new cranks (and bottom
    bracket), but those are cheap.

    --

    David L. Johnson

    __o | "What am I on? I'm on my bike, six hours a day, busting my ass. _`\(,_ | What are you on?"
    --Lance Armstrong (_)/ (_) |
     
  3. Pete Biggs

    Pete Biggs Guest

    Appkiller wrote:
    > or am I confused? Can I take a 53/39 crank + 13-26 cassette with small cage rear der and slap a 50
    > big ring and a 13-29 cassette on and expect it to not explode the rear der (if you haven't figured
    > it out already, I am running Campy)?

    No problem regarding capacity, but what model and year derailleur?......

    David L. Johnson wrote:
    > My only question would be the max sprocket size for the rear derailleur, which for most Campy
    > short & med cage derailleurs is 26 IIRC.

    Depends on the exact model. Many of them are rated 29T now. In any case, they tend to cope with a
    little more than the official max. If pushed one or two teeth, at worst there would be slight
    rubbing in bottom gear which probably won't do any significant harm. It helps to use a chain as
    short as possible for the big-big (existing chain may be longer than strictly necessary).

    ~PB
     
  4. On Thu, 04 Sep 2003 00:07:08 +0100, Pete Biggs wrote:

    >> My only question would be the max sprocket size for the rear derailleur, which for most Campy
    >> short & med cage derailleurs is 26 IIRC.
    >
    > Depends on the exact model. Many of them are rated 29T now. In any case, they tend to cope with a
    > little more than the official max. If pushed one or two teeth, at worst there would be slight
    > rubbing in bottom gear which probably won't do any significant harm. It helps to use a chain as
    > short as possible for the big-big (existing chain may be longer than strictly necessary).

    Well, I did try this once, with a 30-tooth cog on an 8-speed setup, and it was not really usable. No
    matter how I set up the chain or the tensioner on the derailleur, the upper jockey wheel rode on,
    not slightly rubbed on, the sprocket. It was not good. A 29 is smaller, but only by one tooth.

    --

    David L. Johnson

    __o | Deserves death! I daresay he does. Many that live deserve _`\(,_ | death. And some that die
    deserve life. Can you give it to (_)/ (_) | them? Then do not be too eager to deal out death in
    judgement. -- J. R. R. Tolkien
     
  5. Pete Biggs

    Pete Biggs Guest

    David L. Johnson wrote:

    >>> My only question would be the max sprocket size for the rear derailleur, which for most Campy
    >>> short & med cage derailleurs is 26 IIRC.
    >>
    >> Depends on the exact model. Many of them are rated 29T now. In any case, they tend to cope with a
    >> little more than the official max. If pushed one or two teeth, at worst there would be slight
    >> rubbing in bottom gear which probably won't do any significant harm. It helps to use a chain as
    >> short as possible for the big-big (existing chain may be longer than strictly necessary).
    >
    > Well, I did try this once, with a 30-tooth cog on an 8-speed setup, and it was not really usable.
    > No matter how I set up the chain or the tensioner on the derailleur, the upper jockey wheel rode
    > on, not slightly rubbed on, the sprocket. It was not good. A 29 is smaller, but only by one tooth.

    Yes I wouldn't suggest pushing it by four teeth but one or two (or even three with a bit of luck)
    should be possible. The derailleur could be a 28T-max model (if not a 29 or 26).

    ~PB
     
  6. Appkiller

    Appkiller Guest

    Apparently, my attempts at googling this question were fairly lame.

    I just googled 13-29 and according to Peter C., this can be done with a short cage der and a 53/39
    (if you absolutely avoid big/big due to chain length). Judicious adjustment of the b-screw is
    necessary. If I go to a 50 in front, the big/big problem would go away (but still a no-no due to
    chain angle).

    Thanks for all your input!

    App
     
  7. Pete-<< Can I take a 53/39 crank + 13-26 cassette with small cage rear der and slap a 50 big ring
    and a 13-29 cassette on and expect it to not explode the rear der (if you haven't figured it out
    already, I am running Campy)? >><BR><BR>

    No problem at all.....

    Peter Chisholm Vecchio's Bicicletteria 1833 Pearl St. Boulder, CO, 80302
    (303)440-3535 http://www.vecchios.com "Ruote convenzionali costruite eccezionalmente bene"
     
  8. David-<< My only question would be the max sprocket size for the rear derailleur, which for most
    Campy short & med cage derailleurs is 26 IIRC.
    >><BR><BR>

    Medium cage and double, max is 28(9s) or 29(10s)...but I have put 13-28/9 on a short cage and
    double(53/39) without problem.

    David-<< Another option, since what you want really are lower gears, is to get a smaller inner ring
    as well as outer ring, and keep the cassette as it is.
    >><BR><BR>

    Smallest on a 135mm BCD is 39t...

    Peter Chisholm Vecchio's Bicicletteria 1833 Pearl St. Boulder, CO, 80302
    (303)440-3535 http://www.vecchios.com "Ruote convenzionali costruite eccezionalmente bene"
     
  9. Pete Biggs

    Pete Biggs Guest

    Appkiller wrote:
    > I just googled 13-29 and according to Peter C., this can be done with a short cage der and a 53/39

    Yeahbut performance does depend on exactly what model short cage you have. More details would help.

    ~PB
     
  10. On Thu, 04 Sep 2003 13:08:38 +0000, Qui si parla Campagnolo wrote:

    > Medium cage and double, max is 28(9s) or 29(10s)...but I have put 13-28/9 on a short cage and
    > double(53/39) without problem.

    May be less if the derailleur is older.
    >
    > David-<< Another option, since what you want really are lower gears, is to get a smaller inner
    > ring as well as outer ring, and keep the cassette as it is.
    >>><BR><BR>
    >
    > Smallest on a 135mm BCD is 39t...

    I did mention it would require new cranks. A 110 or 94mm design will allow much smaller inner rings.

    --

    David L. Johnson

    __o | As far as the laws of mathematics refer to reality, they are not _`\(,_ | certain, and as
    far as they are certain, they do not refer to (_)/ (_) | reality. -- Albert Einstein
     
  11. On Thu, 04 Sep 2003 05:45:25 +0000, Appkiller wrote:

    > Apparently, my attempts at googling this question were fairly lame.
    >
    > I just googled 13-29 and according to Peter C., this can be done with a short cage der and a 53/39
    > (if you absolutely avoid big/big due to chain length).

    Never, never set up a bike with a chain too short to shift into the big-big combination. No,
    you don't want to use it, but you will accidentally shift into it when you are tired and
    looking for a slightly lower gear. What you are suggesting will mean that you walk home, then
    spend a lot of money.

    --

    David L. Johnson

    __o | Some people used to claim that, if enough monkeys sat in front _`\(,_ | of enough
    typewriters and typed long enough, eventually one of (_)/ (_) | them would reproduce the
    collected works of Shakespeare. The internet has proven this not to be the case.
     
  12. Rick Onanian

    Rick Onanian Guest

    On Thu, 04 Sep 2003 18:05:41 GMT, Doug <[email protected]> wrote:
    >> Pete-<< Can I take a 53/39 crank + 13-26 cassette with already, I am running Campy)? >><BR><BR>
    >
    > Peter, are you aware your newsreader quotes in a funky way? I love your posts and single them out,
    > but the layout is taxing to read. Anyone else notice this?

    Yes, I've noticed, and yes, he's aware. I'm sure that many people tell him. I did, in bit of a
    smartass way:

    >> Rick-<< I'm curious as to which newsreader you have that AOHell-
    > Bummer.
    <snip>
    > Heheh...I guess to each his own; I'm riding bikes that are fit with tissue paper, you use a
    > newsreader that's no better. Good for us! <G>

    That quote in context: http://groups.google.com/groups?hl=en&lr=&ie=UTF-
    8&threadm=oprubq9cvow8gzvw%40news.east.cox.net&rnum=1&prev=/groups%3Fhl%3Den%26lr%3D%26ie%3DISO-
    8859-1%26q%3Daohell%2Bonanian%26btnG%3DGoogle%2BSearch

    > Doug
    --
    Rick Onanian
     
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