halfstep impossible?

Discussion in 'Cycling Equipment' started by Gvw, Feb 11, 2004.

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  1. Gvw

    Gvw Guest

    My current gearing for my tourbike is a 44-36-22 crank with a standard 12-14-16-18-20-23-26-30-34
    cassette. Since my 44 alu needs replacement and I almost never use the high gears I thought about
    replacing it with a 42 steel one. Also replacing the cassette with an (expensive) custom 13-15-17-18-19-21-24-28-
    34. This would give me tight spacing between 50 and 70 inch. But looking at the gearchart I noticed
    using a 38 tooth outer ring and a 12-34 cassette would give me a great touring setup. I found a 38
    tooth 94mm ring, alu not steel. Current front derailleur is deore xt. Current shifters downtube.

    For halfstep I need some special road front derailleur?? My seattube is 31mm, this makes a halfstep
    front derailleur not possible?? Any help is most welcom.
     
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  2. Ken

    Ken Guest

    gvw <[email protected]> wrote in news:[email protected]
    reader-1:
    > For halfstep I need some special road front derailleur??

    Half-step made sense 20 years ago when freewheels had big gaps between their 5 cogs. Today,
    cassettes have 9 or 10 cogs and small gaps so half-step just makes life more complicated.
     
  3. gvw <[email protected]> wrote:
    >
    >>For halfstep I need some special road front derailleur??
    >
    "Ken" replied:

    > Half-step made sense 20 years ago when freewheels had big gaps between their 5 cogs. Today,
    > cassettes have 9 or 10 cogs and small gaps so half-step just makes life more complicated.

    I absolutely agree, but if our Dutch friend is determined to persist in this atavism, he or she will
    need to replace the present front derailer, which is designed for a 10 tooth difference in front.

    For half-step-plus-granny setups, you want a "double" type front derailer.

    Since all double-type fronts are designed for 52/53 big rings, best results will require grinding
    away part of the bottom edge of the outer cage plate to match the smaller size chainrings.

    See: http://sheldonbrown.com/derailer-adjustment

    Sheldon "http://www.sheldonbrown.com/gloss_h.html#halfstep" Brown +-------------------------------------------
    +
    | To escape criticism -- | do nothing, say nothing, be nothing. | --Elbert Hubbard |
    +-------------------------------------------+ 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
     
  4. Gvw

    Gvw Guest

    >> Half-step made sense 20 years ago when freewheels had big gaps between their 5 cogs. Today,
    >> cassettes have 9 or 10 cogs and small gaps so half-step just makes life more complicated.

    For touring I normally like wide gears, like my current setup 44-36-22 rings 12-34 cassette. That
    way I can adapt gears quickly in hilly terrain without changing the frontring. But at times I miss
    the tight gears of a road casstte, great for flat terrain or wind. With halfstep I keep the big
    steps but if I prefer a smaller step I can switch to the other ring. It looks convenient to me. Plus
    the cassette is standard, thus cheap.

    With crossover it's the other way around. Tight gears which are great for normal roads but you need
    to use the front derailleur often in hilly terrain.

    With crossover I'm looking at 44-36-22 with 14-16-17-18-19-21-24-28-34. However right in the midle
    of my most used gears ( 50 to 70 inch) there is a lot of shifting necessary between 36/16 and 44/19.
    Anoying. Plus the cassette will be expensive.

    >Sheldon Brown wrote:
    (It's he thank you.)

    > For half-step-plus-granny setups, you want a "double" type front derailer.
    >
    > Since all double-type fronts are designed for 52/53 big rings, best results will require grinding
    > away part of the bottom edge of the outer cage plate to match the smaller size chainrings.

    So a standard 105 derailleur would not or barely work.

    >David L. Johnson wrote:

    >> For halfstep I need some special road front derailleur??
    >No, it should work OK. If you use STI, though, (I use downtube shifters)

    I use downtube shifters.

    >The curve of the derailleur is optimized, probably, for a 42 or 46 big ring, so the 38 will have
    >more curve than it expects. You also have to worry about the inner plate contacting the inner
    >rings when you are in your "big" ring. But it should be possible to avoid these problems.

    I changed a 44-32-22 to a 40-32-22 once. It shifted very smoothly. No contact anywhere.

    >> My seattube is 31mm, this makes a halfstep front derailleur not possible??

    >I can't imagine why the seattube diameter should matter in this.

    I thought the maximun diameter road derailleurs can take was 28mm, my mistake.

    I think I'll order a 38 outer ring and try the halfstep setup without chancing the front derailleur.
    If it does not work out I switch my setup to 44-36-22, 14-16-17-18-19-21-24-28-34.

    Thank you all for your replies.
     
  5. Pete Biggs

    Pete Biggs Guest

    gvw wrote:
    > My current gearing for my tourbike is a 44-36-22 crank with a standard 12-14-16-18-20-23-26-30-
    > 34 cassette. Since my 44 alu needs replacement and I almost never use the high gears I thought
    > about replacing it with a 42 steel one. Also replacing the cassette with an (expensive) custom
    > 13-15-17-18-19-21-24-28-34.

    Why bother with half-step when you could have a closer cassette instead?

    What about making up something like the following custom job:

    14-15-16-17-19-21-24-28-34 with 48-34-22 ?

    I use 14-15-16-17-19-21-24-27-30 with 50-39-26 on my tourer and it's PDG.

    ~PB
     
  6. I wrote:

    >> For half-step-plus-granny setups, you want a "double" type front derailer.
    >>
    >> Since all double-type fronts are designed for 52/53 big rings, best results will require grinding
    >> away part of the bottom edge of the outer cage plate to match the smaller size chainrings.
    >
    A shy peson asked:
    >
    > So a standard 105 derailleur would not or barely work.

    You want a standard _double_ 105 for this application, not the _triple_ model, even though you've
    got 3 rings.

    > I think I'll order a 38 outer ring

    Good luck finding one!

    Sheldon "Outer 38s Aren't Arboreal" Brown +-------------------------------------------------------+
    | I am too much of a skeptic to deny the possibility | of anything. --T.H. Huxley |
    +-------------------------------------------------------+ 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
     
  7. Pete Biggs

    Pete Biggs Guest

    gvw wrote:
    > For touring I normally like wide gears, like my current setup 44-36-22 rings 12-34 cassette. That
    > way I can adapt gears quickly in hilly terrain without changing the frontring. But at times I miss
    > the tight gears of a road casstte, great for flat terrain or wind.

    But the beauty of triple 9-speed is that you can have both. You can have the near-equivalent of an
    old-style racing block at the small end but with a few wider-spaced granny gears added. You *can*
    have your cake and eat it. It's just a question of selecting just the right size sprockets and
    chainrings that suit you to enable you to stay in the middle ring most of the time and use the
    smallest steps at medium & high speeds (when you need them most). That is worth some investment in
    custom cassettes & chainsets, if needs be.

    > With halfstep I keep the big steps but if I prefer a smaller step I can switch to the other ring.
    > It looks convenient to me.

    Surely it's more convenient to stay on the same ring more of the time?

    ~PB
     
  8. Pete Biggs

    Pete Biggs Guest

    > gvw wrote:
    >> For touring I normally like wide gears, like my current setup 44-36-22 rings 12-34 cassette. That
    >> way I can adapt gears quickly in hilly terrain without changing the frontring. But at times I
    >> miss the tight gears of a road casstte, great for flat terrain or wind.

    I can see the advantage of having a "looser" cassette when it comes to rapid changes in gradients on
    rolling terrain or for urban cycling when you're accelerating and braking a lot, but it's not all
    that much of a big deal to change up more than one rear gear at once. I do understand what you're
    getting at but I just think on balance that halfstep is not as good as the ratios I suggested. To be
    fair, there is no absolutely perfect solution; good luck with whatever you try.

    ~PB
     
  9. gvw <[email protected]> wrote in message news:<[email protected]>...
    > My current gearing for my tourbike is a 44-36-22 crank with a standard 12-14-16-18-20-23-26-30-34
    > cassette. Since my 44 alu needs replacement and I almost never use the high gears I thought about
    > replacing it with a 42 steel one. Also replacing the cassette with an (expensive) custom 13-15-17-18-19-21-24-28-
    > 34. This would give me tight spacing between 50 and 70 inch.....

    Current triple derailleurs are optimised for 10-12 tooth differential between the outer cogs. So why
    not replace the 44 with another 44 or with a 46.

    Since you are changing the cassette anyway, you could make one yourself. With a 12-34 HG-50 cassette
    and a 11-32 HG-50 or HG-70 cassette, you could remove the rivets and make your own cassette with
    close ratios in the middle and wider ones at both ends (or at the bottom).

    For example, on one bike, my rings are 44-34-22, and my cassette is: 12-14-15-16-17-19-21-25-32 On
    another, my rings are 48-38-24 and my cassette is: 13-15-16-17-18-20-23-26-34

    The result, on either bike is close ratios between 28 and 85 gear-inches. But an advantage over half-
    step is that the mid ranges (44 to 65 gear-inches) are all accessible successively on the middle
    ring, and ditto for the high ranges (55 to 85 gear-inches) on the large ring. With the little
    overlap in the close ratios and the extra range offered by the 12, 25 and 32 cogs, it means I rarely
    shift back and forth between rings, unless the terrain or the wind changes drastically.

    See http://www.sheldonbrown.com/gears for a calculator and http://www.sheldonbrown.com/k7.html for
    an explanation on how to build one's cassette.
     
  10. One often-overlooked problem with half-step gearing is that the chain will often try to ride between
    the two closely-spaced chainrings. To make it work well, you need to reduce the spacing between
    those rings, something I used to accomplish back in the day by simply bending the outer chainring in
    (by bending the part of the chainring where it attaches to the spider).

    In general, the closer the two chainrings are in size, the closer together they need to be for
    proper shifting. A 7-tooth-or-greater differential seemed to work fine, but anything closer needed
    some handiwork.

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

    "gvw" <[email protected]> wrote in message news:[email protected]...
    > My current gearing for my tourbike is a 44-36-22 crank with a standard 12-14-16-18-20-23-26-30-34
    > cassette. Since my 44 alu needs replacement and I almost never use the high gears I thought about
    > replacing it with a 42 steel one. Also replacing the cassette with an (expensive) custom 13-15-17-18-19-21-24-28-
    > 34. This would give me tight spacing between 50 and 70 inch. But looking at the gearchart I
    > noticed using a 38 tooth outer ring and a 12-34 cassette would give me a great touring setup. I
    > found a 38 tooth 94mm ring, alu not steel. Current front derailleur is deore xt. Current shifters
    > downtube.
    >
    > For halfstep I need some special road front derailleur?? My seattube is 31mm, this makes a
    > halfstep front derailleur not possible?? Any help is most welcom.
     
  11. Gvw

    Gvw Guest

    Thanks for your reply.

    Michel Gagnon wrote:
    > For example, on one bike, my rings are 44-34-22, and my cassette is: 12-14-15-16-17-19-21-25-32 On
    > another, my rings are 48-38-24 and my cassette is: 13-15-16-17-18-20-23-26-34
    >
    > The result, on either bike is close ratios between 28 and 85 gear-inches. But an advantage over
    > half-step is that the mid ranges (44 to 65 gear-inches) are all accessible successively on the
    > middle ring, and ditto for the high ranges (55 to 85 gear-inches) on the large ring.

    I need smaller steps in the low gears. I almost never use 44/12. I sacrificed the top gear for an
    extra midle gear. I like the midrange but I suspect you use more cogs than I do. With the big ring I
    use the first four cogs (sometimes 5) With the middle ring I use the middle 5 (sometimes 1 more in
    the front) With the small ring I use 5 cogs.

    > See http://www.sheldonbrown.com/gears for a calculator

    I prefer easygear. www.bikepages.ultimade.nl

    > and http://www.sheldonbrown.com/k7.html for an explanation on how to build one's cassette.

    It looks like I may have to build a custom cassette myself. Did you file the cogs openings to get it
    on the hub next to the other cogs in the intended way? Or did you slide them together with no
    changes at all? If so, did you notice any loss of shifting quality?
     
  12. Gvw

    Gvw Guest

    Thanks for your reply.

    Mike Jacoubowsky wrote:

    > One often-overlooked problem with half-step gearing is that the chain will often try to ride
    > between the two closely-spaced chainrings. To make it work well, you need to reduce the spacing
    > between those rings, something I used to accomplish back in the day by simply bending the outer
    > chainring in (by bending the part of the chainring where it attaches to the spider).
    >
    > In general, the closer the two chainrings are in size, the closer together they need to be for
    > proper shifting. A 7-tooth-or-greater differential seemed to work fine, but anything closer needed
    > some handiwork.

    It seems halfstep is just to complicated for to small an advantage over crossover.
     
  13. Gvw

    Gvw Guest

    Thanks for your reply.

    Pete Biggs wrote:

    >>With halfstep I keep the big steps but if I prefer a smaller step I can switch to the other ring.
    >>It looks convenient to me.
    >
    > Surely it's more convenient to stay on the same ring more of the time?

    It is. The bigger gaps in a halfstep system allows a greater range on the midle ring and thus you
    can stay on that ring longer. However given the complexity of the derailleur setup and potential
    unknown other problems I think I'll use a normal crossover. Halfstep is just to complex for very few
    advantages.
     
  14. Gvw

    Gvw Guest

    Thanks for your reply.

    Sheldon Brown wrote:

    > A shy peson asked:

    I'm not shy. My email adres is my full and real name. It even hints at my country. Thats more than
    most emailers reveal.

    > You want a standard _double_ 105 for this application, not the _triple_ model, even though you've
    > got 3 rings.

    Thanks for the help I would not have thought of that but after reading various replies I concluded
    halfstep is to complex for to few advantages. So I won't try it.

    >> I think I'll order a 38 outer ring
    >
    > Good luck finding one!

    I found one at www.sjscycles.com I bought a TA 40 tooth outer compact sice chainring in the past
    and thought they would have a 38 for 104mm aswell but I can only find a 38 (and even a 40) for the
    midle ring.

    Since I'll switch to crossover gearing I'll use a standard steel (a bonus in my book) 44 and a
    custom 14-16-17-18-19-21-24-28-34 cassette.

    Once again thanks for the help.
     
  15. gvw wrote:

    >>> I think I'll order a 38 outer ring
    >>
    I commented:
    >>
    >> Good luck finding one!
    >
    > I found one at www.sjscycles.com

    ...or did you?

    > I bought a TA 40 tooth outer compact sice chainring in the past and thought they would have a 38
    > for 104mm aswell but I can only find a 38 (and even a 40) for the midle ring.

    Sounds like you _didn't_ find one. :-(

    Sheldon "Highpath Engineering Would Probably Make One For You, But Not Cheap" Brown +------------------------------------
    +
    | Love truth, but pardon error. | --Voltaire |
    +------------------------------------+ 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
     
  16. Pete Biggs

    Pete Biggs Guest

    gvw wrote:
    >>> With halfstep I keep the big steps but if I prefer a smaller step I can switch to the other
    >>> ring. It looks convenient to me.
    >>
    >> Surely it's more convenient to stay on the same ring more of the time?
    >
    > It is. The bigger gaps in a halfstep system allows a greater range on the midle ring and thus you
    > can stay on that ring longer.

    I understand the point but you'd need to shuffle front gears back and forth when the fine changes
    were required. That's not convenient.

    ~PB
     
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