Problem find Chainwheel for Half Step Gearing

Discussion in 'Cycling Equipment' started by Pooh, Jan 30, 2003.

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  1. Pooh

    Pooh Guest

    I have the following setup: 26" Specialized Rockhopper an older double butted chro-mo handmade frame
    that I like and use as a utility bike. My riding area is hilly, with fairly steep hills.

    My gearing is 21 speeds with a Bontrager 4-arm 104 mm BCD triple
    44/32/22 tooth gears And a hyperglide 7 speed cassette rear from Harris Cyclery with
    44/32/1/1/1/1/13 tooth gears.

    Using the Effective Cycling logarithmic gear chart in chapter 5, I laid out my setup and came up
    with a half step if I replace my 32 tooth chainwheel with a 41 optimal, or 42 tooth chain ring. I
    believe this result is correct.

    My problem: I can't seem to find a 41 or 42 tooth gear to install in the middle gear position. The
    gears I did find have the bolt counter bore on the pedal side of the gear meaning that it is for the
    third chainwheel position. Of course, if I reverse the gear then the machined ramps for the granny
    gear are lost. I also tried this on my Shimano LX 4-arm 104 mm BCD and found that the chainwheel is
    not reversable from the outside to middle position (meaning that it does not fit and there is
    interference).

    45. Do I still want to continue on this line of reasoning?
    46. Is half step gearing a reasonable thing still
    47. If I continue, what make and brand of gear should I be looking at?
    48. Would I be happier keeping what I have and pocket my $34 on a nice meal?
     
    Tags:


  2. Jon Isaacs

    Jon Isaacs Guest

    >1. Do I still want to continue on this line of reasoning?

    Is this a bike you ride on the road? If so then half step gearing makes sense.

    >2. Is half step gearing a reasonable thing still

    If you are willing to understand it and deal with the sometimes slower somewhat more confusing
    shifting sequences. Properly done, they quite simple.

    >3. If I continue, what make and brand of gear should I be looking at?

    If Sheldon doesn't have it, it is probably pretty hard to find. Look around and find an old bike
    with a 110-7? bolt pattern triple crank. Those cranks are the ones that you can buy just about
    anything for.

    It could give you a reasonably tall top gear as well, something of a problem with a compact drive,
    setup, your 44-13 is pretty low, something like an 82 inch gear. You could choose something like a
    50-47-26 and work from there.

    >4. Would I be happier keeping what I have and pocket my $34 on a nice meal?

    Probably.

    Jon Isaacs
     
  3. Pooh wrote:
    > I have the following setup: 26" Specialized Rockhopper an older double butted chro-mo handmade
    > frame that I like and use as a utility bike. My riding area is hilly, with fairly steep hills.
    >
    > My gearing is 21 speeds with a Bontrager 4-arm 104 mm BCD triple
    > 44/32/22 tooth gears And a hyperglide 7 speed cassette rear from Harris Cyclery with
    > 34/29/24/20/17/15/13 tooth gears.
    >
    > Using the Effective Cycling logarithmic gear chart in chapter 5, I laid out my setup and came up
    > with a half step if I replace my 32 tooth chainwheel with a 41 optimal, or 42 tooth chain ring. I
    > believe this result is correct.
    >
    > My problem: I can't seem to find a 41 or 42 tooth gear to install in the middle gear position. The
    > gears I did find have the bolt counter bore on the pedal side of the gear meaning that it is for
    > the third chainwheel position. Of course, if I reverse the gear then the machined ramps for the
    > granny gear are lost. I also tried this on my Shimano LX 4-arm 104 mm BCD and found that the
    > chainwheel is not reversable from the outside to middle position (meaning that it does not fit and
    > there is interference).
    >
    > 1. Do I still want to continue on this line of reasoning?

    No.

    > 2. Is half step gearing a reasonable thing still

    No.

    > 3. If I continue, what make and brand of gear should I be looking at?

    You would need a whole new crankset and front derailer.

    > 4. Would I be happier keeping what I have and pocket my $34 on a nice meal?

    Definitely.

    Here's the relevant entry from my Bicycle Glossary:

    "Half-step Gearing

    "In the days of 4- and 5-speed freewheels, 8- and 10-speed bikes were commonly set up with
    chainwheels that were very close in size, for instance, 46/49, or 47/50. When used with typical
    freewheels of the era, the difference between the two front gears was about half as large as the
    difference between adjacent gears on the freewheel. (One reason for this was that early front
    derailers couldn't handle much more than a 3-tooth difference reliably!)

    "With half-step gearing, the larger shifts are made with the rear derailer, and the front is for
    fine tuning. This allows an 8- or 10-speed set up to have a reasonable range with fairly close
    spacing of the gears. One downside of half-step is that it uses all possible combinations, including
    those that run the chain at a fairly severe angle. This is not a big deal in an 8-speed rig, but is
    kind of marginal for 10-speeds. Another serious disadvantage is that every other shift in the normal
    sequence is a double shift (front and rear derailers simultaneously).

    "Half-step gearing is most suitable for riding in flat terrain, where shifting is rare. For bicycles
    with few speeds, it does allow finer gradations to get as close to the "ideal" gear for the
    particular wind conditions as possible.

    "Modern shift patterns use larger jumps on the chainwheels to select general ranges of gears, and
    fairly closely-spaced 7-or-more-speed clusters for the fine tuning. This greatly simplifies the
    shifting pattern, allowing constant adjustment to different grades in rolling terrain, with only
    occasional need for double shift."

    Sheldon "An Idea Whose Time Has Gone" Brown +-------------------------------------------+
    | Never do today what you can do tomorrow. | Something may occur to make you regret | your
    | premature action. --Aaron Burr |
    +-------------------------------------------+ 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. Matt O'Toole

    Matt O'Toole Guest

    "Pooh" <[email protected]> wrote in message news:[email protected]...

    > I have the following setup: 26" Specialized Rockhopper an
    older
    > double butted chro-mo handmade frame that I like and use
    as a utility
    > bike. My riding area is hilly, with fairly steep hills.
    >
    > My gearing is 21 speeds with a Bontrager 4-arm 104 mm BCD
    triple
    > 44/32/22 tooth gears And a hyperglide 7 speed cassette rear from Harris Cyclery
    with
    > 34/29/24/20/17/15/13 tooth gears.
    >
    > Using the Effective Cycling logarithmic gear chart in
    chapter 5, I
    > laid out my setup and came up with a half step if I
    replace my 32
    > tooth chainwheel with a 41 optimal, or 42 tooth chain
    ring. I believe
    > this result is correct.
    >
    > My problem: I can't seem to find a 41 or 42 tooth gear to
    install in
    > the middle gear position. The gears I did find have the
    bolt counter
    > bore on the pedal side of the gear meaning that it is for
    the third
    > chainwheel position. Of course, if I reverse the gear
    then the
    > machined ramps for the granny gear are lost. I also tried
    this on my
    > Shimano LX 4-arm 104 mm BCD and found that the chainwheel
    is not
    > reversable from the outside to middle position (meaning
    that it does
    > not fit and there is interference).

    You'll have a hard time finding anything but standard mountain bike gearing for a 4-bolt 104mm
    crank. That means an innner 22, a middle 32, and an outer 42 or 44. All of them seem to be the
    pinned, ramped, and gated type, which only work in the position they were designed for. I've never
    seen anything else offered for sale. I should never say never, though.

    You'd have better luck with a 110/74 or 58/94 crank. Flat chainrings that will work for outer or
    middle are available for both these sizes, though they're a lot more common for the 110/74. However,
    the smallest inner for a 110/74 is a
    24.

    > 1. Do I still want to continue on this line of reasoning?
    > 2. Is half step gearing a reasonable thing still
    > 3. If I continue, what make and brand of gear should I be
    looking at?
    > 4. Would I be happier keeping what I have and pocket my
    $34 on a nice
    > meal?

    Well, that cassette has a very wide range and the gaps are pretty wide, so half-step is one way of
    dealing with that. If that's what you're trying to accomplish, then it might be a good idea.

    Those are very low gears -- I can only see needing that low a gear if you're pulling a big load, and
    the high wouldn't be high enough for me. Everyone has different needs, though. The main thing is to
    get the gearing that works for you -- not me, John Forrester, or anyone else. So, which specific
    gearing problem are you trying to solve? There may be another solution for the same cost.

    Matt O.
     
  5. Frank Miles

    Frank Miles Guest

    In article <[email protected]>, Pooh <[email protected]> wrote:
    >I have the following setup: 26" Specialized Rockhopper an older double butted chro-mo handmade
    >frame that I like and use as a utility bike. My riding area is hilly, with fairly steep hills.
    >
    >My gearing is 21 speeds with a Bontrager 4-arm 104 mm BCD triple
    >44/32/22 tooth gears And a hyperglide 7 speed cassette rear from Harris Cyclery with
    >34/29/24/20/17/15/13 tooth gears.
    >
    >Using the Effective Cycling logarithmic gear chart in chapter 5, I laid out my setup and came up
    >with a half step if I replace my 32 tooth chainwheel with a 41 optimal, or 42 tooth chain ring. I
    >believe this result is correct.
    >
    >My problem: I can't seem to find a 41 or 42 tooth gear to install in the middle gear position. The
    >gears I did find have the bolt counter bore on the pedal side of the gear meaning that it is for
    >the third chainwheel position. Of course, if I reverse the gear then the machined ramps for the
    >granny gear are lost. I also tried this on my Shimano LX 4-arm 104 mm BCD and found that the
    >chainwheel is not reversable from the outside to middle position (meaning that it does not fit and
    >there is interference).
    >
    >1. Do I still want to continue on this line of reasoning?
    >2. Is half step gearing a reasonable thing still
    >3. If I continue, what make and brand of gear should I be looking at?
    >4. Would I be happier keeping what I have and pocket my $34 on a nice meal?

    I find myself in rare disagreement with Sheldon. I've done lots of riding in the hills --
    particularly touring in mountainous areas -- and *love* 1/2 step & granny. On my one "newer" bike,
    with a 7 (!) speed freewheel/cassette, it's beyond me trying to figure out how to get to that next
    incremental gear if I need to double-shift. With 1/2 step and granny it's simple. Last year I had to
    weld some new side-plates on my commute bike's old front derailleur, but it should be good enough
    for another 20+ years now if I'm nice to its bearings.

    However, he's right in one respect. Front derailleurs really aren't made for it any more. You'll
    have a much easier time getting parts if you adhere to the new mantra.

    -frank
    --
     
  6. Pooh wrote:
    >
    > I have the following setup: 26" Specialized Rockhopper an older double butted chro-mo handmade
    > frame that I like and use as a utility bike. My riding area is hilly, with fairly steep hills.
    >
    > My gearing is 21 speeds with a Bontrager 4-arm 104 mm BCD triple
    > 44/32/22 tooth gears And a hyperglide 7 speed cassette rear from Harris Cyclery with
    > 34/29/24/20/17/15/13 tooth gears.

    The 12-14-17-20-24-29-34 is better spaced for the half-step -- I think this is custom, but
    do-able. I rode something close to this across the US on a loaded tour in the early '90s. Then, I
    think I used:

    26 42 46 12 58.500 94.500 103.500 14 50.143 81.000 88.714 17 41.294 66.706 73.059 20 35.100
    56.700 62.100 24 29.250 47.250 51.750 28 25.071 40.500 44.357 32 21.938 35.438 38.813

    At that particular time the 34t rear had not been "reintroduced," the 29t didn't seem to exist, and
    the Shimano and SunTour r-ders didn't have the wrap-up capacity of max cog capacity of the
    components today. I'm currently running a 48-44 w/ a 11-12-14-17-20-24-29-34 (no granny) for
    experimentation and I do like it very much -- it is quite practical as far as the riding experience
    goes. The 11t is just an extra cog, not part of the half-step. I don't really cross the 48x34
    either. I use the "short cage" XTR derailleur for which Sheldon says he "doesn't sell the silly
    things" (and I do understand why).

    > Using the Effective Cycling logarithmic gear chart in chapter 5, I laid out my setup and came up
    > with a half step if I replace my 32 tooth chainwheel with a 41 optimal, or 42 tooth chain ring. I
    > believe this result is correct.

    Probably, it sounds about right.

    > My problem: I can't seem to find a 41 or 42 tooth gear to install in the middle gear position.

    As others have pointed out, the 110/74 crank is the best for selection of rings.

    > The gears I did find have the bolt counter bore on the pedal side of the gear meaning that it is
    > for the third chainwheel position.

    This is a persistant problem today when trying to run closely sized chainrings. Some custom work is
    likely to be called for if you really want to push forward on this.

    > Of course, if I reverse the gear then the machined ramps for the granny gear are lost.

    Well for a half-step, you don't need ramps/pins/gates for the middle-big changes. The step is so
    small the front shifting is _very_ crisp. The bigger problem for middle-big changes is that the
    rings cannot typically be placed close enough together. I still mess with half-steps and have two
    set-ups today. If the middle and big rings are not close, then the chain can tend to not shift down
    onto the middle rings so well and may "ride" along the teeth of the middle ring. Consider that the
    step size of the chainrings for a half-step are on the order of that for 1t step racing clusters:
    the rings should ideally be just as close as cogs are, but you'll have difficulting making this so
    because no manufacturers intentionally support the half-step paradigm today.

    The shift from granny to middle might seem bad, but in practice it goes pretty well.

    You haven't mentioned the need for the front derailleur. The half-step front is a special beast and
    again no manufacturers intentionally support the half-step paradigm today. If you really do decide
    to pursue the half-step, just ask again and I can help with some front derailleur advice.

    > I also tried this on my Shimano LX 4-arm 104 mm BCD and found that the chainwheel is not
    > reversable from the outside to middle position (meaning that it does not fit and there is
    > interference).

    Again, consider a 110-74 crank if you really want a half-step plus granny. It looks like Nashbar
    just sold out of their sub-$30 "CPI" 110-74 touring crankset.

    > 1. Do I still want to continue on this line of reasoning?

    Only if you are willing to do plenty of messing around.

    > 2. Is half step gearing a reasonable thing still

    Yes, from the perspective of actually using it. Half-steps are second best to crossovers in ease
    of shifting.

    > 3. If I continue, what make and brand of gear should I be looking at?

    Before I bother with detailed directions, decide you are willing to spend the money and do the work.

    > 4. Would I be happier keeping what I have and pocket my $34 on a nice meal?

    It is unlikely you'll solve the problem for $34, not to mention the fact that half-steps are
    basically custom animals today. Can you get a hooker for $34?

    Also, Sheldon writes on his most excellent site:

    "Another serious disadvantage is that every other shift in the normal sequence is a double shift
    (front and rear derailers simultaneously)."

    This is more true theoretically than practically. You can skip a gear with a half-step. I do it all
    the time. Yes, sometimes we make the double shift, but the upside of it is that it is an easy
    double shift.

    "Half-step gearing is most suitable for riding in flat terrain, where shifting is rare. For bicycles
    with few speeds, it does allow finer gradations to get as close to the "ideal" gear for the
    particular wind conditions as possible."

    I cannot agree with this for modern systems where the rear is indexed and gated and the front shifts
    are so crisp w/ the closely toothed rings. If the land is flat and the road is straight, you won't
    be shifting too much with any gear system.

    "Modern shift patterns use larger jumps on the chainwheels to select general ranges of gears, and
    fairly closely-spaced 7-or-more-speed clusters for the fine tuning. This greatly simplifies the
    shifting pattern, allowing constant adjustment to different grades in rolling terrain, with only
    occasional need for double shift."

    True, but the double shift of the modern crossover systems is a bit of a pain when it does finally
    need to take place. The half-step double shift is much easier and quite straightforward; but you'll
    be doing it a lot more often.

    Mostly I think half-steps survive mainly for weirdo gear-heads like myself who like to experiment.
    Most people put 9 or 10 cogs on the back, shift crossover and say "I'm done." That said, if I were
    to leave on a loaded tour today, I would probably put the following on my bike:

    26 42 46 11 63.818 103.091 112.909 12 58.500 94.500 103.500 14 50.143 81.000 88.714 17
    41.294 66.706 73.059 20 35.100 56.700 62.100 24 29.250 47.250 51.750 29 24.207 39.103 42.828
    34 20.647 33.353 36.529

    I don't consider the gears on a bike used for an actual tour experimental. The half-step shouldn't
    quite be dead in my opinion.

    But due to evil hype marketeers and evil publically held monopolistic corporations, too little
    choice exists in the marketplace. None of us weirdos can find the parts we want at the LBS. (Yes,
    that was a bad joke.)
     
  7. Pooh

    Pooh Guest

    Thanks Sheldon, actually I read your dictionary entry a couple of days ago and that is what got me
    confused since what you wrote is reasonable about the chain flex, and why I posted it here. Thanks
    for following up. I'll save my money on other endeavors.

    /Wynn/

    Sheldon Brown <[email protected]> wrote in message
    news:<[email protected]>... -snip-
    > > 1. Do I still want to continue on this line of reasoning?
    > No.
    >
    > > 2. Is half step gearing a reasonable thing still
    > No.
    >
    > > 3. If I continue, what make and brand of gear should I be looking at?
    > You would need a whole new crankset and front derailer.
    >
    > > 4. Would I be happier keeping what I have and pocket my $34 on a nice meal?
    > Definitely.
    >
    > Here's the relevant entry from my Bicycle Glossary: "Half-step Gearing "In the days of 4- and
    > 5-speed freewheels, 8- and 10-speed bikes were commonly set up with chainwheels that were very
    > close in size, for instance, 46/49, or 47/50. When used with typical freewheels of the era, the
    > difference between the two front gears was about half as large as the difference between adjacent
    > gears on the freewheel. (One reason for this was that early front derailers couldn't handle much
    > more than a 3-tooth difference reliably!)
    >
    > "With half-step gearing, the larger shifts are made with the rear derailer, and the front is for
    > fine tuning. This allows an 8- or 10-speed set up to have a reasonable range with fairly close
    > spacing of the gears. One downside of half-step is that it uses all possible combinations,
    > including those that run the chain at a fairly severe angle. This is not a big deal in an 8-speed
    > rig, but is kind of marginal for 10-speeds. Another serious disadvantage is that every other shift
    > in the normal sequence is a double shift (front and rear derailers simultaneously).
    >
    > "Half-step gearing is most suitable for riding in flat terrain, where shifting is rare. For
    > bicycles with few speeds, it does allow finer gradations to get as close to the "ideal" gear for
    > the particular wind conditions as possible.
    >
    > "Modern shift patterns use larger jumps on the chainwheels to select general ranges of gears, and
    > fairly closely-spaced 7-or-more-speed clusters for the fine tuning. This greatly simplifies the
    > shifting pattern, allowing constant adjustment to different grades in rolling terrain, with only
    > occasional need for double shift."
    >
    > Sheldon "An Idea Whose Time Has Gone" Brown +-------------------------------------------+
    > | Never do today what you can do tomorrow. | Something may occur to make you regret | your
    > | premature action. --Aaron Burr |
    > +-------------------------------------------+ 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
     
  8. Jeff Wills

    Jeff Wills Guest

    "Matt O'Toole" <[email protected]> wrote in message
    news:<[email protected]>...
    > You'll have a hard time finding anything but standard mountain bike gearing for a 4-bolt 104mm
    > crank. That means an innner 22, a middle 32, and an outer 42 or 44. All of them seem to be the
    > pinned, ramped, and gated type, which only work in the position they were designed for. I've never
    > seen anything else offered for sale. I should never say never, though.
    >

    With modern CNC machinery, anything short of anti-gravity is possible. I picked this up off
    another list:

    " For those folks looking for custom chainrings and other exotic drivetrain parts, I'd like to call
    attention to a good source. The owner, Colin Aub, makes stuff for me and other funny outfits,
    including Ringling Bros. (which needs very large chainrings for its tiny clown cycles). His web site
    is http://www.warhawkindustries.com "

    I agree that half-step gearing with modern 8- or 9-speed cassettes is probably an exercise in
    silliness.

    Jeff
     
  9. A Muzi

    A Muzi Guest

    "Pooh" <[email protected]> wrote in message news:[email protected]...
    > I have the following setup: 26" Specialized Rockhopper an older double butted chro-mo handmade
    > frame that I like and use as a utility bike. My riding area is hilly, with fairly steep hills.
    >
    > My gearing is 21 speeds with a Bontrager 4-arm 104 mm BCD triple
    > 44/32/22 tooth gears And a hyperglide 7 speed cassette rear from Harris Cyclery with
    > 34/29/24/20/17/15/13 tooth gears.
    >
    > Using the Effective Cycling logarithmic gear chart in chapter 5, I laid out my setup and came up
    > with a half step if I replace my 32 tooth chainwheel with a 41 optimal, or 42 tooth chain ring. I
    > believe this result is correct.
    >
    > My problem: I can't seem to find a 41 or 42 tooth gear to install in the middle gear position. The
    > gears I did find have the bolt counter bore on the pedal side of the gear meaning that it is for
    > the third chainwheel position. Of course, if I reverse the gear then the machined ramps for the
    > granny gear are lost. I also tried this on my Shimano LX 4-arm 104 mm BCD and found that the
    > chainwheel is not reversable from the outside to middle position (meaning that it does not fit and
    > there is interference).
    >
    > 1. Do I still want to continue on this line of reasoning?
    > 2. Is half step gearing a reasonable thing still
    > 3. If I continue, what make and brand of gear should I be looking at?
    > 4. Would I be happier keeping what I have and pocket my $34 on a nice meal?

    Did you think about a 110mm crank? Best ring selection including 44 and 42, and very available
    everywhere. Don't see 41s though. You would have to swap the 22 for a 24 if you use a 110/74. Just
    a thought.

    --
    Andrew Muzi http://www.yellowjersey.org Open every day since 1 April 1971
     
  10. On Fri, 31 Jan 2003 09:46:31 -0500, Jon Isaacs wrote:

    >>I agree that half-step gearing with modern 8- or 9-speed cassettes is probably an exercise in
    >>silliness.
    >>
    >>Jeff
    >
    > Actually it works quite nicely with 7 speed cassettes and 8 speed as well. The advantage is that
    > one can have a wide range of gears and yet at the same time close ratio gears, the advantage of a
    > straight block and a 12-32 at the same time.
    >
    > I did it for quite some time but the issue is indeed getting the correct chain rings. For the
    > gearing I was using, a 50-47 would have been ideal but not was not readily available.

    For some years I used a 110/74 BCD crankset with 28, 44 & 48 T chainrings to half-step a 7-speed
    that used the Shimano 13-34 K cassette. The spacing was fine and the range was good. However, beyond
    7 it does seem to be rather a lot of bother to me. _For me_ the spacing and range on 8 and
    especially on 9 speed systems can be set up so that the steps are as close as I want them, and the
    range as broad, but the shifting pattern is significantly easier to operate than half-stepping.

    Others may not agree. I've seen email from some folks who feel that anything more than 4-5"
    difference in adjacent gears is too much. For them, those pesky 1-tooth integer steps on cassettes
    are just simply too broad, and they feel halfstepping is good because it lets them get the
    ultra-fine granularity they desire. Personally I can't see it.
     
  11. Jeff Wills

    Jeff Wills Guest

    "A Muzi" <[email protected]> wrote in message news:<[email protected]>...
    >
    > Did you think about a 110mm crank? Best ring selection including 44 and 42, and very available
    > everywhere. Don't see 41s though. You would have to swap the 22 for a 24 if you use a 110/74. Just
    > a thought.

    Since the original poster said he had a Rockhopper, I think a crank/BB transplant would be like
    putting Campy on a Varsity BUT...

    The TA Zephyr cranks and chainrings could accomodate just about any gearing weirdness you could
    think of. I got this off of the Harris Cyclery site:

    "
    T.A. Zephyr 110/74/56 Triple This unique design takes full-sized 110 mm BCD chainrings for the
    middle and outer positions. For the granny ring, there are two sets of holes, so you can choose
    either 74 mm for sizes down to 24 teeth or 56 mm for a super-low 20 or 22 tooth stump-pulling
    gear. Lengths available: 150 - 155 - 160 - 162.5 - 165 167.5 - 170 - 172.5 - 175 - 177.5 - 180
    - 185 mm. "

    Harris Cyclery also lists 41-tooth 110mm bolt pattern chainrings:
    http://www.sheldonbrown.com/harris/chainrings.html#110

    Jeff
     
  12. Jon Isaacs wrote:
    >
    > >I agree that half-step gearing with modern 8- or 9-speed cassettes is probably an exercise in
    > >silliness.
    > >
    > >Jeff
    >
    > Actually it works quite nicely with 7 speed cassettes and 8 speed as well. The advantage is that
    > one can have a wide range of gears and yet at the same time close ratio gears, the advantage of a
    > straight block and a 12-32 at the same time.

    True, very true. Here's the double I've been messing with again:

    44 48 11 106.000 115.636 12 97.167 106.000 14 83.286 90.857 17 68.588 74.824 20 58.300
    63.600 24 48.583 53.000 29 40.207 43.862 34 34.294 37.412

    I put this on one of my 10 yo steel race bikes. It works pretty well in practice. The high is about
    eq to a 53x12 and the low is eq to a
    39x30. The average step size is under 9%. The 11t is simply a extra cog thrown on the end (not part
    of the half-step and the 34t is technically part of the half step but to use it would mean a
    complete chain cross, so I throw that one away.

    > I did it for quite some time but the issue is indeed getting the correct chain rings. For the
    > gearing I was using, a 50-47 would have been ideal but not was not readily available.

    Wait till the Flat Power True Believers find out and march death to your door for having a 6.2% step
    size. They shall smelt thine chainrings! (Sort of like Smite Thine Enemies.)

    > The half step shifts can be fast and sure, something that is somewhat unexpected because most
    > riders are only familiar with shifting the front chainrings in large steps of 10 or more teeth.
    > This slows down the shift and makes it less precise.

    I agree.

    > The reason the front can be fast and sure is simply that, unlike in the rear, the shift is
    > effective as soon as the chain is over the first tooth. In the rear the cog set much travel about
    > 1/2 revolution before the shift actually is made because the chain is still pulling from the
    > original teeth.
    >
    > Bottom line: Half step gearing could be fast and effective, giving shift sequences that are as
    > close as a racers straight block and as wide as a tourists granny gears.

    Absolutely, and that is why I used a half-step with granny when I rode across the country. It worked
    wonderfully.

    > But the chain rings that are necessary for this are not readily available, if at all.

    The 48 and 44 (or 46 and 42) aren't hard to find and you can even use the non-optimal 130-74 crank
    to make it happen, since you can get these rings for the 130 circle too.

    > Now in the future, if electronic shifting is developed, then it is possible that there would be a
    > move back to half step shifting because it would be realively simple to program a microprocessor
    > to follow the sequence.

    Now we know where you were leading! I kind of like that idea.

    > The reason I dumped the half-step gearing is that the 1984 Sugino Chainrings that I had did not
    > work well with STI, the spacing was not quite right for a narrow chain and the chain would drop in
    > between the two rings at times.

    Yes, since the % step is about the same as that of 1t cassette increments, the rings shouldn't
    spaced apart more 3 mm. I don't know any rings made this way so I tolerate the occassional miss.
    I've been meaning to do some grinding in the workshop, but I'm fighting the True Believers in a Holy
    War, so I just don't have the resources.

    > But when it was adjusted and working, it was a neat thing.

    I think the front derailleur is the biggest single problem. No one makes a half-step front anymore.
    I have some tricks up my sleeve.

    One weakness not mentioned is that I find I tend to put a lot of turns onto only a couple of cogs.
    Four "adjacent" gears exist on any two adjacent cogs -- my 14 & 17 cogs get a good workout. That
    wouldn't be a problem in the UniGlide days, but it is in the Hyperglide days.
     
  13. Pooh

    Pooh Guest

    I'm going to give this a shot and see how it works. I'll see if I can find a 110 and the gears which
    now looks like 44/42/24. I'm planning on looking at my bike clubs bone yard and perhaps I'll find
    what I need there. A few of you have emailed to me with offerings, and that may work also.

    -Wynn

    "A Muzi" <[email protected]> wrote in message news:<[email protected]>...
    > "Pooh" <[email protected]> wrote in message
    > news:[email protected]...
    > > I have the following setup: 26" Specialized Rockhopper an older double butted chro-mo handmade
    > > frame that I like and use as a utility bike. My riding area is hilly, with fairly steep hills.
    > >
    > > My gearing is 21 speeds with a Bontrager 4-arm 104 mm BCD triple
    > > 44/32/22 tooth gears And a hyperglide 7 speed cassette rear from Harris Cyclery with
    > > 34/29/24/20/17/15/13 tooth gears.
    > >
    > > Using the Effective Cycling logarithmic gear chart in chapter 5, I laid out my setup and came up
    > > with a half step if I replace my 32 tooth chainwheel with a 41 optimal, or 42 tooth chain ring.
    > > I believe this result is correct.
    > >
    > > My problem: I can't seem to find a 41 or 42 tooth gear to install in the middle gear position.
    > > The gears I did find have the bolt counter bore on the pedal side of the gear meaning that it is
    > > for the third chainwheel position. Of course, if I reverse the gear then the machined ramps for
    > > the granny gear are lost. I also tried this on my Shimano LX 4-arm 104 mm BCD and found that the
    > > chainwheel is not reversable from the outside to middle position (meaning that it does not fit
    > > and there is interference).
    > >
    > > 1. Do I still want to continue on this line of reasoning?
    > > 2. Is half step gearing a reasonable thing still
    > > 3. If I continue, what make and brand of gear should I be looking at?
    > > 4. Would I be happier keeping what I have and pocket my $34 on a nice meal?
    >
    > Did you think about a 110mm crank? Best ring selection including 44 and 42, and very available
    > everywhere. Don't see 41s though. You would have to swap the 22 for a 24 if you use a 110/74. Just
    > a thought.
     
  14. Pooh

    Pooh Guest

    > Did you think about a 110mm crank? Best ring selection including 44 and 42, and very available
    > everywhere. Don't see 41s though. You would have to swap the 22 for a 24 if you use a 110/74. Just
    > a thought.

    Success, I found a Sugino VP 5 arm 175 mm in my junk bin. It has elliptical chainwheels at 24/38T.
    The larger bolt center diameter appears to be 110. I'm contacting my friends to see it any have the
    42/44 tooth chainwheels not being used. I'm assuming no trouble exists in mixing elliptical and
    circular chainwheels.

    The current front derailleur is a reliable Shimano Alivio, nothing special. I have several other
    spares of Suntour that I can use. What feature in the front derailleur am I to look for. A longer
    cage or shorter?

    -Wynn
     
  15. Mark Boyd

    Mark Boyd Guest

    On Fri, 31 Jan 2003, Pooh wrote:

    > > Did you think about a 110mm crank? Best ring selection including 44 and 42, and very available
    > > everywhere. Don't see 41s though. You would have to swap the 22 for a 24 if you use a 110/74.
    > > Just a thought.
    >
    > Success, I found a Sugino VP 5 arm 175 mm in my junk bin. It has elliptical chainwheels at
    > 24/38T. The larger bolt center diameter appears to be 110. I'm contacting my friends to see it
    > any have the
    > 42/44 tooth chainwheels not being used. I'm assuming no trouble exists in mixing elliptical and
    > circular chainwheels.
    >
    > The current front derailleur is a reliable Shimano Alivio, nothing special. I have several other
    > spares of Suntour that I can use. What feature in the front derailleur am I to look for. A longer
    > cage or shorter?

    The inner plate on Shimano MTB derailleurs, like the Alivio, is designed for a minimum of an 8 tooth
    difference between the middle and big rings. Half step needs half of that <grin>, so an MTB
    derailleur will not work. Assuming you aren't using indexed shifters, you could use an inexpensive
    Shimano road derailleur. If you are using indexed shifters, you'll have to do major surgery - use a
    Dremel tool with a cut-off disk - on the inner plate of a MTB front derailleur.

    Mark <http://www.cs.unca.edu/~boyd/bicycling.html
     
  16. Jeff Wills

    Jeff Wills Guest

    [email protected] (Pooh) wrote in message news:<[email protected]>...
    > > Did you think about a 110mm crank? Best ring selection including 44 and 42, and very available
    > > everywhere. Don't see 41s though. You would have to swap the 22 for a 24 if you use a 110/74.
    > > Just a thought.
    >
    > Success, I found a Sugino VP 5 arm 175 mm in my junk bin. It has elliptical chainwheels at
    > 24/38T. The larger bolt center diameter appears to be 110. I'm contacting my friends to see it
    > any have the
    > 42/44 tooth chainwheels not being used. I'm assuming no trouble exists in mixing elliptical and
    > circular chainwheels.
    >
    > The current front derailleur is a reliable Shimano Alivio, nothing special. I have several other
    > spares of Suntour that I can use. What feature in the front derailleur am I to look for. A longer
    > cage or shorter?
    >
    > -Wynn

    The front derailleur suitable for half-step gearing will have the inner and outer plates nearly the
    same size and shape. If you look at an "alpine" front derailleur, you'll see that the inner cage
    plate projects downward much farther than the outer.

    Bloody heck... it's a fairly narrow span from the top to bottom rings. You may be able to get away
    with a double front derailleur.

    Cage length has little to do with it, except that you'll have to be sure the tail end of the cage
    doesn't drag on the chainstay- another reason to go with a double front derailleur.

    *Ideally* you should try to find a Shimano RSX double front, I think. These were made for two
    chainrings, but with a tighter curve on the cage (RSX used 46 tooth maximum). Hard to find, though.

    Jeff
     
  17. Mark Boyd wrote:
    >

    > Assuming you aren't using indexed shifters, you could use an inexpensive Shimano road derailleur.

    I don't think even those work quite right -- the inner plate and screw at the back of the cage hang
    down a bit too much. I think the Campy road derailleurs are marginally better. I wish I could find
    the old SunTour Edge "medium cage" front derailleur -- it was perfect for a half-step, light,
    robust, and best of all, cheap. Muzi has that Huret (I think) front that looks favorable for a
    half-step.
     
  18. A number of times I have been seduced by half-step gearing because of the lack of duplicates. Many
    so called 24 or 27 speed setups have so many duplicates that they have fewer distinct gears than a
    15 or 18 speed half-step plus bulldog (sometimes called granny) setup.

    HOWEVER, in practice I found myself tending to just ride on the middle chainring, using the bulldog
    when necessary but rarely using the big ring. I've observed a lot of other people doing this as
    well. Once I conceded that I didn't actually use the half-step feature I decided that I could find
    some other way to use 3 chainrings. Also when I began to use 7 speed clusters and then 8 speed (no
    9's or 10's yet) I decided that they were spaced so closely that half way between wasn't different
    enough to be worth the bother of shifting, the momentum loss (especially of a double shift) would
    mean that the new lower gear wouldn't feel any easier than the slightly higher gear I'd just left.

    Half-step plus bulldog is elegant but I never found it to be especially useful. I do have it on a
    restored mid 70's Follis which I look at but rarely ride and if I did ride it I'd probably quickly
    fall into riding mostly on the middle ring.

    Bob Taylor
     
  19. Pete Geurds

    Pete Geurds Guest

    I have a 3 x 5 half step on an older Schwinn. I find it works out pretty good in rolling terrain. I
    can usually get in position where I can go big ring on the down slopes and middle ring on the up
    slopes. Any more and I just shift the rear. Remember you are under no obligation to shift a half
    step in exact sequence. If you tried to shift a crossover geared bike in exact sequence from
    smallest to largest gear you'd go just as wacky.

    Pete Geurds Douglassville, PA
     
  20. Robert Taylor wrote:
    >
    > A number of times I have been seduced by half-step gearing because of the lack of duplicates. Many
    > so called 24 or 27 speed setups have so many duplicates that they have fewer distinct gears than a
    > 15 or 18 speed half-step plus bulldog (sometimes called granny) setup.
    >
    > HOWEVER, in practice I found myself tending to just ride on the middle chainring, using the
    > bulldog when necessary but rarely using the big ring. I've observed a lot of other people doing
    > this as well. Once I conceded that I didn't actually use the half-step feature I decided that I
    > could find some other way to use 3 chainrings. Also when I began to use 7 speed clusters and then
    > 8 speed (no 9's or 10's yet) I decided that they were spaced so closely that half way between
    > wasn't different enough to be worth the bother of shifting, the momentum loss (especially of a
    > double shift) would mean that the new lower gear wouldn't feel any easier than the slightly higher
    > gear I'd just left.
    >
    > Half-step plus bulldog is elegant but I never found it to be especially useful. I do have it on a
    > restored mid 70's Follis which I look at but rarely ride and if I did ride it I'd probably quickly
    > fall into riding mostly on the middle ring.

    Even though I have half-steps...

    For most people, I think that 9sp's have pretty much killed off half-steps, and 10sp's will probably
    finish the job. You are right about one thing -- if one wants to shift half-step they must accept
    the cost of being concious of what they are doing. You can be pretty oblivious with STI/Ergo and
    "get it right." People would rather not think about it. And there is nothing wrong with that
    (probably there is everything right with it).
     
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