Basic Gear Question

Discussion in 'Road Cycling' started by Al, Jul 1, 2003.

Thread Status:
Not open for further replies.
  1. Al

    Al Guest

    I guess I have 24 (3/8) gears available to me, not counting the bad-idea combinations. I'm finding
    that, riding around the paved bike trails here in town, that I'm using the biggest gear on the front
    pretty consistently, only delving into the mid sized gear when going up some fairly steep grades. I
    suspect I'll use a broader range once I get on some trails outside of town. My question is the
    following: are the 24 gears meant to have a strictly linear relationship? In other words if I'm on
    the big gear in front and the biggest in the rear (for argument's sake only,) will that always have
    more resistance than the middle gear in the front and the smallest gear in the back... or is there
    overlap? And if so, is that just incidental or actually something people take advantage of? I hope
    this question made sense to somebody... :)

    Thanks, Al
     
    Tags:


  2. Archer

    Archer Guest

    In article <[email protected]>, [email protected] says...
    > I guess I have 24 (3/8) gears available to me, not counting the bad-idea combinations. I'm finding
    > that, riding around the paved bike trails here in town, that I'm using the biggest gear on the
    > front pretty consistently, only delving into the mid sized gear when going up some fairly steep
    > grades. I suspect I'll use a broader range once I get on some trails outside of town. My question
    > is the following: are the 24 gears meant to have a strictly linear relationship? In other words if
    > I'm on the big gear in front and the biggest in the rear (for argument's sake only,) will that
    > always have more resistance than the middle gear in the front and the smallest gear in the back...
    > or is there overlap? And if so, is that just incidental or actually something people take
    > advantage of? I hope this question made sense to somebody... :)

    There is lots of overlap. What that allows you to do is have gear ratios spaced closer together than
    you could get otherwise (since your minimum gear spacing is one tooth).

    --
    David Kerber An optimist says "Good morning, Lord." While a pessimist says "Good Lord,
    it's morning".

    Remove the ns_ from the address before e-mailing.
     
  3. Al

    Al Guest

    [This followup was posted to rec.bicycles.misc and a copy was sent to the cited author.]

    In article <[email protected]>, ns_archer1960 @ns_hotmail.com says...
    > In article <[email protected]>, [email protected] says...
    > > I guess I have 24 (3/8) gears available to me, not counting the bad-idea combinations. I'm
    > > finding that, riding around the paved bike trails here in town, that I'm using the biggest gear
    > > on the front pretty consistently, only delving into the mid sized gear when going up some fairly
    > > steep grades. I suspect I'll use a broader range once I get on some trails outside of town. My
    > > question is the following: are the 24 gears meant to have a strictly linear relationship? In
    > > other words if I'm on the big gear in front and the biggest in the rear (for argument's sake
    > > only,) will that always have more resistance than the middle gear in the front and the smallest
    > > gear in the back... or is there overlap? And if so, is that just incidental or actually
    > > something people take advantage of? I hope this question made sense to somebody... :)
    >
    > There is lots of overlap. What that allows you to do is have gear ratios spaced closer together
    > than you could get otherwise (since your minimum gear spacing is one tooth).

    Okay thanks - is there a rule of thumb for how one selects the next closest ratio up or down?

    Thanks a bunch! Al
     
  4. Archer

    Archer Guest

    In article <[email protected]>, [email protected] says...
    > [This followup was posted to rec.bicycles.misc and a copy was sent to the cited author.]
    >
    > In article <[email protected]>, ns_archer1960 @ns_hotmail.com says...
    > > In article <[email protected]>, [email protected] says...
    > > > I guess I have 24 (3/8) gears available to me, not counting the bad-idea combinations. I'm
    > > > finding that, riding around the paved bike trails here in town, that I'm using the biggest
    > > > gear on the front pretty consistently, only delving into the mid sized gear when going up
    > > > some fairly steep grades. I suspect I'll use a broader range once I get on some trails
    > > > outside of town. My question is the following: are the 24 gears meant to have a strictly
    > > > linear relationship? In other words if I'm on the big gear in front and the biggest in the
    > > > rear (for argument's sake only,) will that always have more resistance than the middle gear
    > > > in the front and the smallest gear in the back... or is there overlap? And if so, is that
    > > > just incidental or actually something people take advantage of? I hope this question made
    > > > sense to somebody... :)
    > >
    > > There is lots of overlap. What that allows you to do is have gear ratios spaced closer together
    > > than you could get otherwise (since your minimum gear spacing is one tooth).
    >
    > Okay thanks - is there a rule of thumb for how one selects the next closest ratio up or down?

    I don't know; I never bother. I just hit the next cog up or down, depending on which way I need to
    shift. If I run out of cogs, I jump to the next chainwheel and go to about the middle of the
    cluster, and see how that works. I think split-shifting to get the possible smallest jump will
    usually (though not necessarily always) be more effort than it's worth.

    --
    David Kerber An optimist says "Good morning, Lord." While a pessimist says "Good Lord,
    it's morning".

    Remove the ns_ from the address before e-mailing.
     
  5. Bobqzzi

    Bobqzzi Guest

    On Tue, 1 Jul 2003 12:44:16 -0500, Al <[email protected]> wrote:

    >I guess I have 24 (3/8) gears available to me, not counting the bad-idea combinations. I'm finding
    >that, riding around the paved bike trails here in town, that I'm using the biggest gear on the
    >front pretty consistently, only delving into the mid sized gear when going up some fairly steep
    >grades. I suspect I'll use a broader range once I get on some trails outside of town. My question
    >is the following: are the 24 gears meant to have a strictly linear relationship? In other words if
    >I'm on the big gear in front and the biggest in the rear (for argument's sake only,) will that
    >always have more resistance than the middle gear in the front and the smallest gear in the back...
    >or is there overlap? And if so, is that just incidental or actually something people take advantage
    >of? I hope this question made sense to somebody... :)
    >
    >Thanks, Al

    Go to www.sheldonbrown.com/gears and enter in your cogs/sprockets and you will be able to see how
    much, and where the overlap is.
     
  6. On Tue, 01 Jul 2003 12:44:16 +0000, Al wrote:

    > I guess I have 24 (3/8) gears available to me, not counting the bad-idea combinations. I'm finding
    > that, riding around the paved bike trails here in town, that I'm using the biggest gear on the
    > front pretty consistently, only delving into the mid sized gear when going up some fairly steep
    > grades. I suspect I'll use a broader range once I get on some trails outside of town. My question
    > is the following: are the 24 gears meant to have a strictly linear relationship? In other words if
    > I'm on the big gear in front and the biggest in the rear (for argument's sake only,) will that
    > always have more resistance than the middle gear in the front and the smallest gear in the back...
    > or is there overlap?

    There is a large amount of overlap. Of those 24 gear combinations, typically the largest 3 or 4 on
    the big ring are only there, and the smallest 3 of 4 are only on the granny ring, but all of those
    in between are available, plus or minus a bit, on more than one combination. Some available with
    either of the three chainrings.

    > And if so, is that just incidental or actually something people take advantage of? I hope this
    > question made sense to somebody... :)

    There are those who claim great advantages of having lots of overlap. I fail to see them. Mostly the
    overlap is a legacy of earlier days, when you had fewer cogs in back.

    --

    David L. Johnson

    __o | The trouble with the rat race is that even if you win you're _`\(,_ | still a rat. --Lilly
    Tomlin (_)/ (_) |
     
  7. On Tue, 01 Jul 2003 14:21:46 +0000, archer wrote:

    >> > There is lots of overlap. What that allows you to do is have gear ratios spaced closer together
    >> > than you could get otherwise (since your minimum gear spacing is one tooth).
    >>
    >> Okay thanks - is there a rule of thumb for how one selects the next closest ratio up or down?
    >
    > I don't know; I never bother. I just hit the next cog up or down, depending on which way I need to
    > shift. If I run out of cogs, I jump to the next chainwheel and go to about the middle of the
    > cluster, and see how that works. I think split-shifting to get the possible smallest jump will
    > usually (though not necessarily always) be more effort than it's worth.

    Hmm. First you say (that was you, archer) that the point of the overlap is to get closer-spaced
    gears than are available in one-tooth jumps, then you say you never bother to do that. No one does.
    You are trying to rationalize the choice of gears -- which aren't really made for the most rational
    of reasons.

    A 1-tooth jump in the back gives 8% or so change in gear ratio in the high end, and less than 5% in
    the low end. That is a fine-enough jump for practically any rider. Most, in fact, space out the cogs
    wider in the low end because such fine jumps are not significant enough a change.

    --

    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 (_)/ (_) |
     
  8. The gears overlap a great deal.My strategy for using them on a twelve speed road bike is to
    consider it as two different six speeds, one which uses the large chainring for flatter terrain,
    and one which uses the smaller chainring for more hilly roads. I do not cross shift to get closer
    ratios. HTH

    Ernie

    Al wrote:

    > I guess I have 24 (3/8) gears available to me, not counting the bad-idea combinations. I'm finding
    > that, riding around the paved bike trails here in town, that I'm using the biggest gear on the
    > front pretty consistently, only delving into the mid sized gear when going up some fairly steep
    > grades. I suspect I'll use a broader range once I get on some trails outside of town. My question
    > is the following: are the 24 gears meant to have a strictly linear relationship? In other words if
    > I'm on the big gear in front and the biggest in the rear (for argument's sake only,) will that
    > always have more resistance than the middle gear in the front and the smallest gear in the back...
    > or is there overlap? And if so, is that just incidental or actually something people take
    > advantage of? I hope this question made sense to somebody... :)
    >
    > Thanks, Al
     
  9. David Kerber

    David Kerber Guest

    In article <[email protected]>, [email protected] says...
    > On Tue, 01 Jul 2003 14:21:46 +0000, archer wrote:
    >
    > >> > There is lots of overlap. What that allows you to do is have gear ratios spaced closer
    > >> > together than you could get otherwise (since your minimum gear spacing is one tooth).
    > >>
    > >> Okay thanks - is there a rule of thumb for how one selects the next closest ratio up or down?
    > >
    > > I don't know; I never bother. I just hit the next cog up or down, depending on which way I need
    > > to shift. If I run out of cogs, I jump to the next chainwheel and go to about the middle of the
    > > cluster, and see how that works. I think split-shifting to get the possible smallest jump will
    > > usually (though not necessarily always) be more effort than it's worth.
    >
    > Hmm. First you say (that was you, archer) that the point of the overlap is to get closer-spaced
    > gears than are available in one-tooth jumps, then you say you never bother to do that. No one
    > does. You are trying to

    OK. I didn't know if anyone else used those fine spacings or not; all I said was that they were
    there, and I assumed there was a reason for them. If that's not the reason, then what IS the reason?
    Why not get big-enough differences in the chainrings so that you don't have any overlap? (Or maybe
    just one gear's worth of overlap. I would think a
    52/30 front would come close to doing it, and that is what the big and smalls are on most triples.

    > rationalize the choice of gears -- which aren't really made for the most rational of reasons.
    >
    > A 1-tooth jump in the back gives 8% or so change in gear ratio in the high end, and less than 5%
    > in the low end. That is a fine-enough jump for practically any rider. Most, in fact, space out the
    > cogs wider in the low end because such fine jumps are not significant enough a change.

    Yes, but the percentage tends to be about the same all along the range, within what is possible with
    integral jumps in the number of teeth: 24 to 26 is the same percentage as 12 to 13.

    --
    Dave Kerber Fight spam: remove the ns_ from the return address before replying!

    REAL programmers write self-modifying code.
     
  10. On Tue, 01 Jul 2003 21:15:15 +0000, David Kerber wrote:

    > Yes, but the percentage tends to be about the same all along the range, within what is possible
    > with integral jumps in the number of teeth: 24 to 26 is the same percentage as 12 to 13.

    That is because the low end is spaced out more. Certainly a jump from 24 to 25 is smaller than a
    jump from 12 to 13. An "ideal" gear jump is probably on the order of 6-8%. Any finer and the change
    is not nocitable, any wider and there is too abrupt a change.

    --

    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.
     
  11. Coal Porter

    Coal Porter Guest

    On Tue, 1 Jul 2003 21:15:15 -0400, David Kerber <[email protected]_ids.net> wrote:

    |OK. I didn't know if anyone else used those fine spacings or not; all I |said was that they were
    there, and I assumed there was a reason for |them. If that's not the reason, then what IS the
    reason? Why not get |big-enough differences in the chainrings so that you don't have any |overlap?
    (Or maybe just one gear's worth of overlap. I would think a
    |52/30 front would come close to doing it, and that is what the big and
    |smalls are on most triples.

    At first glance, it would seem to make sense to use all the gears, but at the extremes,e.g. big
    chainring and toothiest cog, the angle of the chain reduces the efficiency of your stroke.

    Further, that big differential, 52 to 30, may not shift great and should result in increased
    chainwear.

    All in all, it ain't so bad the way it is. If you have a low enough gear to climb "your" terrain,
    most peeps can adapt to the rest.

    bcnu-c.porter.
     
  12. Al <[email protected]> wrote:
    : I guess I have 24 (3/8) gears available to me, not counting the bad-idea combinations. I'm
    : finding that, riding around the paved bike trails here in town, that I'm using the biggest gear
    : on the front pretty consistently, only delving into the mid sized gear when going up some fairly
    : steep grades.

    al, are you by chance in rochester, mn? -- your news server is mayo.edu. i spend my weeks in
    rochester contracting at IBM. somebody* screwd up bad and built the town 50 miles too far west
    missing the stunningly beautiful missisippi river valley and placing the town squarely next to the
    stunningly average zumbro river (i'd say valley but there isn't). there are some hills in town ..
    but you'll be digging. probably literally. most of the trails are flat, too. there are some nice
    rural rides, though. take 11th ave se out of town south and follow it as it turns into simpson road
    and finally county road 1. there's one hill on the return that's pretty steep. but fairly short.
    it's near my favorite spot in all of the rochester area: the road does a 180 and drops into a
    heavily wooded depression where you're surrounded by rockface. at the bottom is a bridge over a
    fishing stream (and people often are). then you climb back out.

    or take highway 14 miles 50 miles east to winona turn around and climb out of the mississippi river
    valley. it's about a 1.5 mile consistent 6% or so
    climb. not sure on the grade but it's about as good as minnesota gets.

    the rochester active sports club (http://www.rasc-mn.org/) also has some route maps that are nicely
    done (follow "Road Biking" to "Bike Routes").

    on the other hand i've ridden my fixed gear around rochester and never missed having gears.

    * i'm being polite. it was the mayo brothers.
    --
    david reuteler [email protected]
     
  13. Archer

    Archer Guest

    In article <[email protected]>, [email protected] says...
    > On Tue, 01 Jul 2003 21:15:15 +0000, David Kerber wrote:
    >
    > > Yes, but the percentage tends to be about the same all along the range, within what is possible
    > > with integral jumps in the number of teeth: 24 to 26 is the same percentage as 12 to 13.
    >
    > That is because the low end is spaced out more. Certainly a jump from 24 to 25 is smaller than a
    > jump from 12 to 13. An "ideal" gear jump is probably on the order of 6-8%. Any finer and the
    > change is not nocitable, any wider and there is too abrupt a change.

    That's exactly what I was saying, and is the reason for the varying spacing as you go up
    the cluster.

    --
    David Kerber An optimist says "Good morning, Lord." While a pessimist says "Good Lord,
    it's morning".

    Remove the ns_ from the address before e-mailing.
     
  14. Archer

    Archer Guest

    In article <[email protected]>, [email protected] says...
    > On Tue, 1 Jul 2003 21:15:15 -0400, David Kerber <[email protected]_ids.net> wrote:
    >
    > |OK. I didn't know if anyone else used those fine spacings or not; all I |said was that they were
    > there, and I assumed there was a reason for |them. If that's not the reason, then what IS the
    > reason? Why not get |big-enough differences in the chainrings so that you don't have any |overlap?
    > (Or maybe just one gear's worth of overlap. I would think a
    > |52/30 front would come close to doing it, and that is what the big and
    > |smalls are on most triples.
    >
    > At first glance, it would seem to make sense to use all the gears, but at the extremes,e.g. big
    > chainring and toothiest cog, the angle of the chain reduces the efficiency of your stroke.

    Though with a double, that would be less of a problem than with a triple.

    > Further, that big differential, 52 to 30, may not shift great and should result in increased
    > chainwear.

    I agree, but how often would you be shifting the front?

    > All in all, it ain't so bad the way it is. If you have a low enough gear to climb "your" terrain,
    > most peeps can adapt to the rest.

    I guess the real reason might be that it means more people can find a range they like off the rack
    and not have to shift the front much at all.

    --
    David Kerber An optimist says "Good morning, Lord." While a pessimist says "Good Lord,
    it's morning".

    Remove the ns_ from the address before e-mailing.
     
  15. Al

    Al Guest

    In article <[email protected]>, [email protected] says... [...]
    > al, are you by chance in rochester, mn? -- your news server is mayo.edu. i spend my weeks in
    > rochester contracting at IBM. somebody* screwd up bad and built the town 50 miles too far west
    > missing the stunningly beautiful missisippi river valley and placing the town squarely next to the
    > stunningly average zumbro river (i'd say valley but there isn't). there are some hills in town ..
    > but you'll be digging. probably literally. most of the trails are flat, too. there are some nice
    > rural rides, though. take 11th ave se out of town south and follow it as it turns into simpson
    > road and finally county road 1. there's one hill on the return that's pretty steep. but fairly
    > short. it's near my favorite spot in all of the rochester area: the road does a 180 and drops into
    > a heavily wooded depression where you're surrounded by rockface. at the bottom is a bridge over a
    > fishing stream (and people often are). then you climb back out.
    >
    > or take highway 14 miles 50 miles east to winona turn around and climb out of the mississippi
    > river valley. it's about a 1.5 mile consistent 6% or so
    > climb. not sure on the grade but it's about as good as minnesota gets.
    >
    > the rochester active sports club (http://www.rasc-mn.org/) also has some route maps that are
    > nicely done (follow "Road Biking" to "Bike Routes").
    >
    > on the other hand i've ridden my fixed gear around rochester and never missed having gears.
    >
    > * i'm being polite. it was the mayo brothers.

    Hi David, you bet, I'm here in the Med City. Thanks for the suggestions, I'll check them out. I did
    a little riding in my road bike days maybe 10 years ago outside of town and seem to remember a few
    hills. In town, 20th street SW is short but steep (messed up by construction now I think.) I don't
    think I ever was really in decent biking shape, and I recall being nearly stationary on that street
    a few times and being harassed by a nasty little dog. I found a few hills SW of town too - but the
    areas you mentioned are largely unexplored by me. Thanks for the suggestion! Next time you see a guy
    badly in need of a manzierre humping up one of the hills, it might be me :)

    - Al
     
  16. Coal Porter

    Coal Porter Guest

    On Wed, 2 Jul 2003 08:08:51 -0400, archer <[email protected]_hotmail.com> wrote:

    <In article <[email protected]>, <[email protected] says... <> On
    Tue, 1 Jul 2003 21:15:15 -0400, David Kerber <> <[email protected]_ids.net> wrote: <> <> |OK. I didn't
    know if anyone else used those fine spacings or not; all I <> |said was that they were there, and I
    assumed there was a reason for <> |them. If that's not the reason, then what IS the reason? Why not
    get <> |big-enough differences in the chainrings so that you don't have any <> |overlap? (Or maybe
    just one gear's worth of overlap. I would think a <> |52/30 front would come close to doing it, and
    that is what the big and <> |smalls are on most triples. <> <> At first glance, it would seem to
    make sense to use all the gears, but <> at the extremes,e.g. big chainring and toothiest cog, the
    angle of the <> chain reduces the efficiency of your stroke. < <Though with a double, that would be
    less of a problem than with a triple.

    I think it depends on whether you're paying attention. I use a double and have not adapted well to
    triples when I've ridden them, too many choices.

    <> Further, that big differential, 52 to 30, may not shift great and <> should result in increased
    chainwear. < <I agree, but how often would you be shifting the front?

    It's not how often, it's when you're testing yourself or being tested that you want the equipment to
    work as best as it can and when it doesn't, at a minimum, you remember.

    < <> All in all, it ain't so bad the way it is. If you have a low enough <> gear to climb "your"
    terrain, most peeps can adapt to the rest. < <I guess the real reason might be that it means more
    people can find a <range they like off the rack and not have to shift the front much at all.

    What kind of terrain are you doing? In CT, if you go east-west, it's like surfing, up a ridge then
    down then up. And the roads were built ages ago, so there's really no steady grades: I do a lot of
    front chain ring shifts. I acknowledge the overlap in gears. I always assumed that it was an
    inherent design compromise particularly as the range widens for peeps that are not A1 athletes. I
    don't miss the gears that I theoretically could have as long as I have the low that I need and I
    have always looked at the bike as far more evolved than the engine.

    all the best-c.porter.
     
  17. Archer

    Archer Guest

    In article <[email protected]>, [email protected] says...
    > On Wed, 2 Jul 2003 08:08:51 -0400, archer <[email protected]_hotmail.com> wrote:
    >
    > <In article <[email protected]>, <[email protected] says... <> On
    > Tue, 1 Jul 2003 21:15:15 -0400, David Kerber <> <[email protected]_ids.net> wrote: <> <> |OK. I didn't
    > know if anyone else used those fine spacings or not; all I <> |said was that they were there, and
    > I assumed there was a reason for <> |them. If that's not the reason, then what IS the reason? Why
    > not get <> |big-enough differences in the chainrings so that you don't have any <> |overlap? (Or
    > maybe just one gear's worth of overlap. I would think a <> |52/30 front would come close to doing
    > it, and that is what the big and <> |smalls are on most triples. <> <> At first glance, it would
    > seem to make sense to use all the gears, but <> at the extremes,e.g. big chainring and toothiest
    > cog, the angle of the <> chain reduces the efficiency of your stroke. < <Though with a double,
    > that would be less of a problem than with a triple.
    >
    > I think it depends on whether you're paying attention. I use a double and have not adapted well to
    > triples when I've ridden them, too many choices.
    >
    > <> Further, that big differential, 52 to 30, may not shift great and <> should result in increased
    > chainwear. < <I agree, but how often would you be shifting the front?
    >
    > It's not how often, it's when you're testing yourself or being tested that you want the equipment
    > to work as best as it can and when it doesn't, at a minimum, you remember.
    >
    > < <> All in all, it ain't so bad the way it is. If you have a low enough <> gear to climb "your"
    > terrain, most peeps can adapt to the rest. < <I guess the real reason might be that it means more
    > people can find a <range they like off the rack and not have to shift the front much at all.
    >
    > What kind of terrain are you doing? In CT, if you go east-west, it's like surfing, up a ridge then
    > down then up. And the roads were built ages ago, so there's really no steady grades: I do a lot of
    > front chain ring shifts. I acknowledge the overlap in gears. I always assumed that it was an
    > inherent design compromise particularly as the range widens for peeps that are not A1 athletes. I
    > don't miss the gears that I theoretically could have as long as I have the low that I need and I
    > have always looked at the bike as far more evolved than the engine.

    I'm in in RI, ride an old Schwinn LeTank 10-speed, and the area I live in has few hills worthy of
    the name. There is one hill where I have to stand on the lowest gear and pull on the bars to get
    enough force to move at all, but that is the only hill around which _requires_ me to get off the big
    ring. Sometimes I'll drop to the small ring if I'm feeling lazy on some of the other smaller ones,
    but rarely.

    --
    David Kerber An optimist says "Good morning, Lord." While a pessimist says "Good Lord,
    it's morning".

    Remove the ns_ from the address before e-mailing.
     
Loading...
Thread Status:
Not open for further replies.
Loading...