indexed steering and handling?

Discussion in 'Cycling Equipment' started by John Albergo, Feb 6, 2003.

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  1. John Albergo

    John Albergo Guest

    The FAQ item states "...there is no possibility of injury or damage from 'indexed' steering head
    bearings". - I would take that to imply no adverse effects on handling. However I have been noticing
    sometimes squirelly handling in low speed maneuvers and can find nothing to blame it on other than
    my steering has become heavily indexed.

    The hub bearings turn freely with no appreciable play, tires are in good shape. Wheels are true
    enough and alignment looks okay. No serious falls. I see no frame cracks. I don't think I've
    developed any balance problems.

    Is it possible for an indexed headset to introduce handling problems during low-speed turns where
    the front wheel is actually involved in "steerng"?
     
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  2. On Thu, 06 Feb 2003 17:51:29 -0500, John Albergo wrote:

    > The FAQ item states "...there is no possibility of injury or damage from 'indexed' steering head
    > bearings". - I would take that to imply no adverse effects on handling. However I have been
    > noticing sometimes squirelly handling in low speed maneuvers and can find nothing to blame it on
    > other than my steering has become heavily indexed.
    >
    > The hub bearings turn freely with no appreciable play, tires are in good shape. Wheels are true
    > enough and alignment looks okay. No serious falls. I see no frame cracks. I don't think I've
    > developed any balance problems.
    >
    > Is it possible for an indexed headset to introduce handling problems during low-speed turns where
    > the front wheel is actually involved in "steerng"?

    Yeah, probably. But we are talking about slow speeds, where injury is not a big risk.

    There are cures for indexed steering. Re-pack the headset with loose balls rather than the usual
    bearing cage, and add one more ball than was there before. Really, replace them all, but put an
    extra in. If that doesn't work, the next step is to knock out the cups and re-install them.

    --

    David L. Johnson

    __o | A mathematician is a machine for turning coffee into theorems. _`\(,_ | -- Paul Erdos
    (_)/ (_) |
     
  3. Jobst Brandt

    Jobst Brandt Guest

    John Albergo writes:

    > Is it possible for an indexed headset to introduce handling problems during low-speed turns where
    > the front wheel is actually involved in "steering"?

    Only when riding no-hands and only after the slack has been taken out so that it "indexes" to a
    preferred position. Otherwise, the clunk when braking on uneven surfaces is highly disturbing to
    the rider.

    Jobst Brandt [email protected] Palo Alto CA
     
  4. Scic

    Scic Guest

    >From: John Albergo

    >Is it possible for an indexed headset to introduce handling problems during
    low-speed turns where the front wheel is actually involved in steerng"?

    It's not so much a "handling" problem as it is a balance problem. A bike needs to lean to turn with
    stability. At low speed, turning the wheel creates instability, i.e., you're forcing it to lean but
    there is not enough forward momentum to keep it from falling over. The squirelliness is the result
    of balance adjustments needed to keep the bike upright. Ever notice how you regain stability in a
    very low speed turn by merely pushing hard on a pedal?

    Sig Chicago
     
  5. Jobst Brandt

    Jobst Brandt Guest

    Sig snipes anonymously:

    >> Is it possible for an indexed headset to introduce handling problems during low-speed turns where
    >> the front wheel is actually involved in steering"?

    > It's not so much a "handling" problem as it is a balance problem. A bike needs to lean to turn
    > with stability. At low speed, turning the wheel creates instability, i.e., you're forcing it to
    > lean but there is not enough forward momentum to keep it from falling over. The squirelliness is
    > the result of balance adjustments needed to keep the bike upright. Ever notice how you regain
    > stability in a very low speed turn by merely pushing hard on a pedal?

    That's the greatest compendium of gobbledygook on bicycle stability seen here in a long time.
    Balancing a bicycle is a dynamic exercise that goes into static balance as forward motion approaches
    zero. Then it becomes a track stand, aka body balancing. "Pushing hard on the pedal" aka
    accelerating is a dynamic effect that causes centrifugal acceleration, the means by which a single
    track vehicle is balanced.

    So back to the question. What effect does a dimpled head bearing have on control?

    Jobst Brandt [email protected] Palo Alto CA
     
  6. Jobst Brandt

    Jobst Brandt Guest

    Sig snipes anonymously:

    >> Is it possible for an indexed headset to introduce handling problems during low-speed turns where
    >> the front wheel is actually involved in steering"?

    > It's not so much a "handling" problem as it is a balance problem. A bike needs to lean to turn
    > with stability. At low speed, turning the wheel creates instability, i.e., you're forcing it to
    > lean but there is not enough forward momentum to keep it from falling over. The squirelliness is
    > the result of balance adjustments needed to keep the bike upright. Ever notice how you regain
    > stability in a very low speed turn by merely pushing hard on a pedal?

    That's the greatest compendium of gobbledygook on bicycle stability seen here in a long time.
    Balancing a bicycle is a dynamic exercise that goes into static balance as forward motion approaches
    zero. Then it becomes a track stand, aka body balancing. "Pushing hard on the pedal" causing
    acceleration is dynamic and causes centrifugal acceleration, the means by which a single track
    vehicle is balanced.

    So back to the question. What effect does a dimpled head bearing have on control?

    Jobst Brandt [email protected] Palo Alto CA
     
  7. John Albergo

    John Albergo Guest

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    Scic wrote:

    >>From: John Albergo
    >>
    >>
    >
    >
    >
    >>Is it possible for an indexed headset to introduce handling problems during
    >>
    >>
    >low-speed turns where the front wheel is actually involved in steerng"?
    >
    >It's not so much a "handling" problem as it is a balance problem. A bike needs to lean to turn with
    >stability. At low speed, turning the wheel creates instability, i.e., you're forcing it to lean but
    >there is not enough forward momentum to keep it from falling over. The squirelliness is the result
    >of balance adjustments needed to keep the bike upright. Ever notice how you regain stability in a
    >very low speed turn by merely pushing hard on a pedal?
    >
    >
    I'm not talking about the increased balance demands of a slow bike. There are vague discontinuities
    when negotiating slow turns that seem to have developed. My balance seems ok; at least I can walk
    around in the dark with my eyes closed, stand on one leg with eyes closed, turning my head about
    and so forth. I don't seem to have balance issues in other realms, just these squirrely moments in
    slow turns.

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    <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> <html> <head> <title></title>
    </head> <body> <br> <br> Scic wrote:<br> <blockquote type="cite"
    cite="[email protected]"> <blockquote type="cite"> <pre
    wrap="">From: John Albergo </pre> </blockquote> <pre wrap=""><!----> </pre> <blockquote
    type="cite"> <pre wrap="">Is it possible for an indexed headset to introduce handling problems
    during </pre> </blockquote> <pre wrap=""><!---->low-speed turns where the front wheel is actually
    involved in steerng"?

    It's not so much a "handling" problem as it is a balance problem. A bike needs to lean to turn with
    stability. At low speed, turning the wheel creates instability, i.e., you're forcing it to lean but
    there is not enough forward momentum to keep it from falling over. The squirelliness is the result
    of balance adjustments needed to keep the bike upright. Ever notice how you regain stability in a
    very low speed turn by merely pushing hard on a pedal? </pre> </blockquote> I'm not talking about
    the increased balance demands of a slow bike. There are vague discontinuities when negotiating
    slow turns that seem to have developed. My balance seems ok; at least I can walk around in the
    dark with my eyes closed, stand on one leg with eyes closed, turning my head about and so forth.
    I don't seem to have balance issues in other realms, just these squirrely moments in slow
    turns. <br> </body> </html>

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  8. John Albergo

    John Albergo Guest

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    [email protected] wrote:

    >John Albergo writes:
    >
    >
    >
    >>Is it possible for an indexed headset to introduce handling problems during low-speed turns where
    >>the front wheel is actually involved in "steering"?
    >>
    >>
    >
    >Only when riding no-hands and only after the slack has been taken out so that it "indexes" to a
    >preferred position. Otherwise, the clunk when braking on uneven surfaces is highly disturbing to
    >the rider.
    >
    >
    No clunks and it definitely has a preferred position; or rather several. Straight ahead and then
    about 30' and 60' on both sides. With bike raised and level I can push the wheel up to about 10' to
    the side and it will return on its own. Push a little further and it will continue to the next stop.
    It's difficult to walk the bike by pushing the seat because you have to give it a good swing to get
    the wheel to move. This is quite noticeable since I negotiate a tight hallway with two 90' turns
    twice a day. Pushing the seat and tilting used to work fine now I have to reach forward and
    manipulate the steerer. The road handling issues are with hands on though. If there is odd movement
    somewhere else I can't find it. The advantage is that parking is more stable when leaning the bike
    against a pole, etc. Reminds me of my old flick-stand.

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    <br> <br> <a class="moz-txt-link-abbreviated"
    href="mailto:[email protected]">[email protected]</a> wrote:<br>
    <blockquote type="cite" cite="[email protected]"> <pre wrap="">John
    Albergo writes:

    </pre> <blockquote type="cite"> <pre wrap="">Is it possible for an indexed headset to introduce
    handling problems during low-speed turns where the front wheel is actually involved in "steering"?
    </pre> </blockquote> <pre wrap=""><!----> Only when riding no-hands and only after the slack has
    been taken out so that it "indexes" to a preferred position. Otherwise, the clunk when braking on
    uneven surfaces is highly disturbing to the rider. </pre> </blockquote> No clunks and it
    definitely has a preferred position; or rather several. Straight ahead and then about 30'
    and 60' on both sides. With bike raised and level I can push the wheel up to about 10' to
    the side and it will return on its own. Push a little further and it will continue to the
    next stop. It's difficult to walk the bike by pushing the seat because you have to give it a
    good swing to get the wheel to move. This is quite noticeable since I negotiate a tight
    hallway with two 90' turns twice a day. Pushing the seat and tilting used to work fine now I
    have to reach forward and manipulate the steerer. The road handling issues are with hands on
    though. If there is odd movement somewhere else I can't find it. The advantage is that
    parking is more stable when leaning the bike against a pole, etc. Reminds me of my old
    flick-stand.<br> <br> <br> </body> </html>

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  9. Ron Hardin

    Ron Hardin Guest

    Scic wrote:
    > A brinelled (pitted, dented) crown race or lower cup will give you notched steering but not
    > instability as long as your hands are on the bars.

    No-handed, you have to repeatedly turn one way or the other to go straight; the no-handed turns are
    fine but the bike is unstable going straight until it's fallen far enough to force you to produce a
    fairly large countersteer each time. You can't do small countersteers, is the problem.
    --
    Ron Hardin [email protected]

    On the internet, nobody knows you're a jerk.
     
  10. Jobst Brandt

    Jobst Brandt Guest

    anonymous writes:

    >> I don't seem to have balance issues in other realms, just these squirrely moments in slow turns.

    > I know your sense of balance isn't the problem. A brinelled (pitted, dented) crown race or lower
    > cup will give you notched steering but not instability as long as your hands are on the bars.

    Hey! Enough of this BS myth and lore. No wonder you snipe from anonymity.

    > Have you had the headset overhauled recently? Have you (or anyone else) crashed? Or hit something
    > hard, perhaps a curb? I would suggest you remove the fork and check if the steerer tube has been
    > bent at the crown. Also check that the crown race and lower cup are seated square to the steerer
    > and headtube.

    http://draco.acs.uci.edu/rbfaq/FAQ/8f.13.html

    Jobst Brandt [email protected] Palo Alto CA
     
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