Max tooth capacity on a front derailleur

Discussion in 'Cycling Equipment' started by Dolan Halbrook, Apr 24, 2003.

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  1. I know i'm not the first to ask about tooth capacity on a front derailleur (and feel free to point
    me to an FAQ), but a while back I asked people on the Phred touring mailing list what gearing they
    were using for loaded touring.

    More than a few people responded that they were using (in the front) something like 26-39-53 (a 27
    tooth difference), or even wider ranges than that. I once tried a similar arrangement on my wife's
    road triple and the front shifting was terrible, even with ramped rings.

    So, i'm wondering, is there some magic front derailleur than can handle more than 22 -23 teeth that
    I don't know about, or are these people just living with substandard front shifting? Does the tooth
    capacity matter more for an STI "brifter" whereas you can get away with more with bar-ends/downtube
    shifters and other things not-necessarily-indexed?

    Thanks in advance, Dolan Halbrook
     
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  2. Dolan Halbrook <[email protected]> wrote:
    >with substandard front shifting? Does the tooth capacity matter more for an STI "brifter" whereas
    >you can get away with more with bar-ends/downtube shifters and other things
    >not-necessarily-indexed?

    Well, with a non-indexed front shifter (or Ergo, as I understand it), you can overshift to get the
    chain through a big gap (effectively using the limit screws as "indexing" to prevent the chain
    actually coming off) and then trim back a way - and you can also trim the front derailleur as you
    switch cogs in the rear. I have to trim mine if I want to use more than the largest three rear
    sprockets with the small chainring, but then I don't want to do that.
    --
    David Damerell <[email protected]> Distortion Field!
     
  3. Paul Kopit

    Paul Kopit Guest

    On Thu, 24 Apr 2003 08:38:55 -0700, "Dolan Halbrook" <[email protected]> wrote:

    >More than a few people responded that they were using (in the front) something like 26-39-53 (a 27
    >tooth difference), or even wider ranges than that. I once tried a similar arrangement on my wife's
    >road triple and the front shifting was terrible, even with ramped rings.

    I know that the Dura Ace triple front derailleur handles 53/39/28 w/o a problem because my tandem is
    that way and it would likely handle the 26 too. It's design is for 53/39/30. I don't know how it
    would index with STI because my system is Ergo.

    I know that a pre microdrive XT or XTR front derailleur will handle
    52/42/26 too. I don't know if it would index.
     
  4. Dolan Halbrook wrote:

    "More than a few people responded that they were using (in the front) something like 26-39-53 (a 27
    tooth difference), or even wider ranges than that."

    WHY would anyone want a 53 on a touring bike? Unless the smallest cog on the back was 16 teeth (or
    his "tour" was the TDF)?

    My highest is 48-12 on mine and I can barely hold cadence in that _without_ panniers!

    While we're on the subject, though, does _anybody_ make a FD with a 20+ tooth capacity that can
    handle a difference of _less_ that 8 teeth between adjacent rings?

    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
     
  5. Steve

    Steve Guest

    "Dolan Halbrook" <[email protected]> wrote in message news
    > More than a few people responded that they were using (in the front)
    something like 26-39-53 (a 27 tooth difference), or even
    > wider ranges than that.

    I'm running a 24-36-50 on my Heron with an Ultegra triple fnt. derailer. I use Campy Centaur Ergo
    shifters and essentially allow it to "overshift" to the next biggest ring, instead of using the
    index type shift up on a Shimano STI system. I have no problems, which would normally manifest
    itself (in the front) as the chain rubbing on the bottom of the derailer cage if there's too much
    spread (say a 52 or larger ring). FWIW, Shimano say's this derailer will handle a 22 tooth spread.

    > Does the tooth capacity matter more for an STI "brifter" whereas you can
    get away with more with bar-ends/downtube
    > shifters and other things not-necessarily-indexed?

    My understanding is that tooth capacity of the front derailer is as much a factor of derailer shape,
    and is not related to the type of shifter. You also have to pay attention, when going wide in the
    front, to the wrap capacity of the rear derailer, especially if using a wide range cassette.

    Also, others have commented on your choice of 26/39/53 for the ring choice, which I assume is a
    result of using a road triple with 130/74 BCD cranks. Much has been written on gearing for loaded
    touring bikes, with a range of 20 to 100 gear inches being the desirable range. You might want to
    think about a 110/74 BCD crank which would (as others have commented) get your gearing into a range
    you might find more appropriate.

    Steve B.
     
  6. Jeff Wills

    Jeff Wills Guest

    "Dolan Halbrook" <[email protected]> wrote in message news:<[email protected]>...
    > More than a few people responded that they were using (in the front) something like 26-39-53 (a 27
    > tooth difference), or even wider ranges than that. I once tried a similar arrangement on my wife's
    > road triple and the front shifting was terrible, even with ramped rings.
    >
    > Thanks in advance, Dolan Halbrook

    My wife's Tour Easy came with 26/42/52 chainrings and a Shimano 105 front derailleur, shifted by
    Grip Shifts. If there were any problems with the shifting, trust me, I'd hear about it.

    Jeff
     
  7. Well, here is the reasoning. My wife's bike shipped with a standard road triple (52-42-30), and I
    wanted to lower her gearing. I already swapped the rear cluster to a MTB long cage der and a 12-34,
    but wanted the lowest possible.

    Reason 1) It's a lot cheaper to swap the granny than buy a new crankset, and 26-34 is quite a low
    combination.

    Reason 2) This bike is not *exclusively* for touring. We do quite a bit of road riding
    (unloaded) as well.

    --Dolan

    "Chris Zacho "The Wheelman"" <[email protected]> wrote in message
    news:[email protected]...
    > Dolan Halbrook wrote:
    >
    > "More than a few people responded that they were using (in the front) something like 26-39-53 (a
    > 27 tooth difference), or even wider ranges than that."
    >
    > WHY would anyone want a 53 on a touring bike? Unless the smallest cog on the back was 16 teeth (or
    > his "tour" was the TDF)?
    >
    > My highest is 48-12 on mine and I can barely hold cadence in that _without_ panniers!
    >
    > While we're on the subject, though, does _anybody_ make a FD with a 20+ tooth capacity that can
    > handle a difference of _less_ that 8 teeth between adjacent rings?
    >
    > 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
     
  8. My biggest issues are these:

    1) We're running Shimano STI (not as much front trim as Ergo).
    2) There are *very* few 9 spd compatible 110/74 cranks left on the market.
    3) I'd like to avoid buying a new crank if possible.

    Thanks, Dolan

    "Steve" <[email protected]> wrote in message
    news:D[email protected]...
    > "Dolan Halbrook" <[email protected]> wrote in message news
    > > More than a few people responded that they were using (in the front)
    > something like 26-39-53 (a 27 tooth difference), or even
    > > wider ranges than that.
    >
    > I'm running a 24-36-50 on my Heron with an Ultegra triple fnt. derailer.
    I
    > use Campy Centaur Ergo shifters and essentially allow it to "overshift" to the next biggest ring,
    > instead of using the index type shift up on a
    Shimano
    > STI system. I have no problems, which would normally manifest itself (in the front) as the chain
    > rubbing on the bottom of the derailer cage if there's too much spread (say a 52 or larger ring).
    > FWIW, Shimano say's
    this
    > derailer will handle a 22 tooth spread.
    >
    > > Does the tooth capacity matter more for an STI "brifter" whereas you can
    > get away with more with bar-ends/downtube
    > > shifters and other things not-necessarily-indexed?
    >
    > My understanding is that tooth capacity of the front derailer is as much a factor of derailer
    > shape, and is not related to the type of shifter. You also have to pay attention, when going wide
    > in the front, to the wrap capacity of the rear derailer, especially if using a wide range
    > cassette.
    >
    > Also, others have commented on your choice of 26/39/53 for the ring
    choice,
    > which I assume is a result of using a road triple with 130/74 BCD cranks. Much has been written on
    > gearing for loaded touring bikes, with a range of 20 to 100 gear inches being the desirable range.
    > You might want to think about a 110/74 BCD crank which would (as others have commented) get your
    > gearing into a range you might find more appropriate.
    >
    > Steve B.
     
  9. According to Sheldon Brown, the Shimano 1997 RSX front der is the only one that can handle a std mtn
    triple with shimano STI shifters. Yech. I guess you have Ergo though, so it's not an issue.

    http://www.sheldonbrown.com/harris/derailers.html#front

    Is the D/A triple front der any different (because of the different triple crank) than say, Ultegra?

    Thanks, Dolan

    "Paul Kopit" <[email protected]> wrote in message
    news:[email protected]...
    > On Thu, 24 Apr 2003 08:38:55 -0700, "Dolan Halbrook" <[email protected]> wrote:
    >
    > >More than a few people responded that they were using (in the front) something like 26-39-53 (a
    > >27 tooth difference), or even wider ranges
    than
    > >that. I once tried a similar arrangement on my wife's road triple and
    the
    > >front shifting was terrible, even with ramped rings.
    >
    > I know that the Dura Ace triple front derailleur handles 53/39/28 w/o a problem because my tandem
    > is that way and it would likely handle the 26 too. It's design is for 53/39/30. I don't know how
    > it would index with STI because my system is Ergo.
    >
    > I know that a pre microdrive XT or XTR front derailleur will handle
    > 52/42/26 too. I don't know if it would index.
     
  10. Paul Kopit

    Paul Kopit Guest

    Maybe some people have tandem bicycles.

    It's difficult for me to think of using something like 53/11 and I don't frequently use 53/12,
    except on the tandem.

    On Thu, 24 Apr 2003 19:42:11 -0400 (EDT), [email protected] (Chris Zacho "The Wheelman") wrote:

    >
    >WHY would anyone want a 53 on a touring bike? Unless the smallest cog on the back was 16 teeth (or
    >his "tour" was the TDF)?
     
  11. Steve

    Steve Guest

    "Dolan Halbrook" <[email protected]> wrote in message ...
    > My biggest issues are these:

    > 1) We're running Shimano STI (not as much front trim as Ergo).

    And you might as well stay with it, as other then the lack of trim in the front, it's a generally
    fine and reliable system.

    > 2) There are *very* few 9 spd compatible 110/74 cranks left on the market.

    The 110/74 rings I use are not 9 spd. compatable per say. They are standard rings for this BCD size
    and are actually 8 spd. vintage. They work just fine with a SRAM PC69 chain. The rear cogsette is 9
    spd. and I have zero shifiting problems.

    > 3) I'd like to avoid buying a new crank if possible.

    Understandable. Still, you have to make choices somewhere as to what's going to be appropriate
    gearing for the scenario's in which she wants to use the bike. You may well find the 26/39/53 is
    well within her capabilties, especially using a wide range rear cassette.

    You do have other options. You can get non-pinned/ramped chainrings in the 130BCD size in 38 and 50
    and a 74 BCD in 24, all for around $60, thus potentially saving the cost of a different b-bracket if
    you change cranks. The only problem with non pinned is the front shifting will suffer slightly. I
    use a 38/54 combo in 130BCD on my go fast bike with STI and am not bothered by not having ramps/pins
    on the 54, but that's me. You can also get TA rings for 130 BCD in 38 and 50 sizes with pins to keep
    the shifting crisp - only problem is that ain't cheap at $54 and $38 ea., plus a cheapo
    74/24 at $12 or so. It keeps the range within the 26 tooth (real) capacity of the derailer. Other
    may well suggest a cheaper source.

    You can also get a new crank and I know you would like to avoid the cost, but sometimes is it's
    the cheapest solution as it gives you much better options down the road - especially the 110/74
    cranks. Sheldon has a Sugino XD300 for $60 with 26/36/46 rings. 110/74 rings are also generally
    pretty cheap.

    Steve B.
     
  12. Steve

    Steve Guest

    "Steve" <[email protected]> wrote in message > ...

    > > 2) There are *very* few 9 spd compatible 110/74 cranks left on the
    market.

    I meant to add that Sugino still makes cost effective 110/74, Rivendell sells both Ritchey 110
    double as well as 110/74 triple, plus TA 110/74's as does Peter White. Cambia has assorted AC,
    Azionic and Raceface stuff. They are also common on e-bay and in other classified sites. The rings
    are about the most commonly available still

    Steve B.
     
  13. >From: [email protected] (Chris Zacho "The Wheelman")

    >While we're on the subject, though, does _anybody_ make a FD with a 20+ tooth capacity that can
    >handle a difference of _less_ that 8 teeth between adjacent rings?
    >

    Don't know if anyone makes one now, but I've an old Suntour Vx on my triple touring bike that has
    half step + granny with a 4 tooth difference between the top two rings and it's so smooth that
    sometimes I have to look down to make sure it shifted. 20 teeth is probably it's limit though. I've
    tried replacing it with something more modern a time or two but nothing I've tried works as well. If
    it ever wears out I guess I'll have to replace the whole bloody drive train.

    George F. Johnson A veteran for peace
     
  14. Paul Kopit <[email protected]> writes:

    > Maybe some people have tandem bicycles.
    >
    > It's difficult for me to think of using something like 53/11 and I don't frequently use 53/12,
    > except on the tandem.

    53/11 is very common among racers around me (meaning in South Africa) and for most it will be Campag
    10s. With 10s you _can_ have the 11 and still a 21 or even 23 and still have a fairly close
    ratio. If you can push 53/11 you have the advantage of an approximately 9% longer gear over
    coompetitors with 53/12; just what one wants on a really flat sprint. Tandem racers I know have
    up to 57/11 on a front double.

    Wessel
     
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