Pitted cones and shells--just how bad is it?

Discussion in 'Cycling Equipment' started by Trent Gregory H, Mar 22, 2003.

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  1. Folks,

    I know that you should check your hubs and overhaul them on a regular basis, but if you fail to
    do so and discover, when you do get around to it, that the cones and / or hub shell have
    developed pits, what would the consequences be, if any, of overhauling them as they are and
    continuing to use them?

    Trent, who doesn't have any trashed hubs, but is curious about such things
     
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  2. Mikeyankee

    Mikeyankee Guest

    Checking for hub play is part of my daily pre- and post-ride inspection. I keep the cones adjusted
    and overhaul all my hubs at least once a year, using new balls. Since I started doing this in '95 or
    thereabouts I have never had to replace a cone and I have one set of wheels with close to 20k miles
    on 'em. Paying attention to your hubs is a good long-term economy -- end of lecture.

    Should you ride those damaged hubs? One consideration is the level of damage you can do. Often the
    cones get pitted before the cup does. So by replacing your cones you can prevent damage to the cup.
    But you are already past that point...

    My hunch is you can probably continue to use them, expecting the cones, cups and balls to wear at
    an accelerating rate. Eventually they will be shot. If this happens a mile from home on your beater
    bike, it will be insignificant. If it happens 200 miles from home on a loaded tour it can be a
    major problem.

    I once bought a beater bike whose bottom bracket axle was badly pitted on both sides. I just cleaned
    it, put in new balls, greased and adjusted it and rode it for a year (~1000 miles, mostly in the
    rain) before finally replacing it. It always had a wee little bit of play, but worked OK.


    Mike Yankee

    (Address is munged to thwart spammers. To reply, delete everything after "com".)
     
  3. Jobst Brandt

    Jobst Brandt Guest

    Trent Gregory Hill writes:

    > I know that you should check your hubs and overhaul them on a regular basis, but if you fail to do
    > so and discover, when you do get around to it, that the cones and/or hub shell have developed
    > pits, what would the consequences be, if any, of overhauling them as they are and continuing to
    > use them?

    I think you are talking about cones and outer race and in these mainly the cone gets pitted from use
    but mainly from overload. The FAQ item on this has been waiting a while to appear but here it is:

    Subject: 8c.6 Wheel Bearing adjustment From: Jobst Brandt <[email protected]> Date:
    Tue, 26 Nov 2002

    Bicycle wheel bearings, as most, require a slight preload so that under load, more than the one ball
    under the cone (inner race) is not carrying the entire load. With proper preload, slight drag should
    be perceptible. This drag is small compared to the drag when the bearing is loaded, drag that we
    cannot feel. Adjusting ball bearings to spin freely unloaded does not reduce operating friction. A
    bearing with clearance has higher drag when loaded than one with proper preload. For high quality
    bearings, preload should be just enough to cause light drag when rotating the axle between thumb and
    forefinger. Low grade bearings will feel slightly lumpy with proper preload.

    Wheels with quick release (QR) axles present an additional problem of altering bearing clearance as
    the QR is closed. Closing the lever requires increasing force with a slight over-center feel near
    the end of the stroke. This lever force arises from compressing the hollow axle and stretching the
    skewer. The ratio of elastic length change between axle and skewer is that of their cross sectional
    area and effective lengths.

    Although small, axle shortening on QR hubs is large enough to affect bearing clearance and should be
    considered when adjusting bearings. They should be adjusted just loose enough so that closing the QR
    leaves no bearing clearance but rather a slight preload. Excessive preload from QR closure is the
    cause of most wheel bearing failures not caused by water intrusion. Clearance, in contrast can be
    felt as disconcerting rattle when encountering road roughness.

    To test for proper adjustment, install the wheel and wiggle the rim side-to-side to determine that
    there is no clearance (rattle), then let the wheel rotate freely to a stop, noting whether it halts
    with a short (indexed) oscillation. If the wheel stops with an oscillating "shudder" at the end of
    motion, bearing preload is too high.

    Adjusting QR force is more than a safety matter. It is also one of bearing life and should be kept
    at a known constant level once the desired closure force has been determined. Rear vertical
    dropouts require a lower and more predictable closure force than was formerly required with axles
    that could move forward from chain tension. Because vertical dropouts do not rely on friction to
    resist chain load, many hubs now have smooth faced jam nuts that do not damage dropout faces as
    older knurl faced ones did.
    ------------------------------

    Jobst Brandt [email protected] Palo Alto CA
     
  4. Tom Ace

    Tom Ace Guest

    [email protected] wrote:

    > Subject: 8c.6 Wheel Bearing adjustment From: Jobst Brandt <[email protected]> Date:
    > Tue, 26 Nov 2002
    >
    > Bicycle wheel bearings, as most, require a slight preload so that under load, more than the one
    > ball under the cone (inner race) is not carrying the entire load. [...]

    Is that worded correctly?

    Tom Ace
     
  5. jobst brandt wrote:

    > Tom Ace writes:
    >
    >>> Bicycle wheel bearings, as most, require a slight preload so that under load, more than the one
    >>> ball under the cone (inner race) is not carrying the entire load. [...]
    >
    >> Is that worded correctly?
    >
    > What part of that is unclear?

    I think it should read something like "... so that under load, more than the one ball ... is
    carrying the load".

    Or alternatively, "so that under load, not only one ball ... is carrying the entire load".

    --
    Benjamin Lewis

    "Love is a snowmobile racing across the tundra and then suddenly it flips over, pinning you
    underneath. At night, the ice weasels come." --Matt Groening
     
  6. Jobst Brandt

    Jobst Brandt Guest

    Tom Ace writes:

    >> Bicycle wheel bearings, as most, require a slight preload so that under load, more than the one
    >> ball under the cone (inner race) is not carrying the entire load. [...]

    > Is that worded correctly?

    What part of that is unclear? Maybe when taken to the extreme, the effect would be more apparent.
    With substantial clearance (assume the bearing balls remain stuck to the outer race), it should be
    evident that the cone will contact only one ball when loaded radially. When rotated, it will then
    drop between two balls before it rides up over the next. This displacement is known as "ball drop"
    and it causes the entire load to be carried by one ball.

    With axial preload, a cup and cone (angular contact) bearing elastically loads all balls of the
    compliment so that a radial load will be distributed among several balls that are already in
    contact. As the FAQ item explains, this can be overdone to the point that the preload is a large
    part of the permissible load and will exceed that limit when its intended load is carried.

    Such overloads occur often because correctly adjusted wheel bearings will be overloaded by tight
    quick release (QR) closure. That is why most wheel bearings should be adjusted on the verge of
    looseness, a looseness that will be taken up when the QR is closed.

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

    Jobst Brandt Guest

    Benjamin Lewis writes:

    >>>> Bicycle wheel bearings, as most, require a slight preload so that under load, more than the one
    >>>> ball under the cone (inner race) is not carrying the entire load. [...]

    >>> Is that worded correctly?

    >> What part of that is unclear?

    > I think it should read something like "... so that under load, more than the one ball ... is
    > carrying the load".

    > Or alternatively, "so that under load, not only one ball ... is carrying the entire load".

    I see. It is a double negative or tries to be and can be ambiguous. I'll reword that if I can.

    Jobst Brandt [email protected] Palo Alto CA
     
  8. Jt

    Jt Guest

    <[email protected]> wrote in message news:[email protected]...
    > Tom Ace writes:
    >
    > >> Bicycle wheel bearings, as most, require a slight preload so that under load, more than the one
    > >> ball under the cone (inner race) is not carrying the entire load. [...]
    >
    > > Is that worded correctly?
    >
    > What part of that is unclear? Maybe when taken to the extreme, the

    I though he was querying if the cone was indeed the inner race.
     
  9. [email protected] wrote:

    >
    > <[email protected]> wrote in message news:[email protected]...
    >> Tom Ace writes:
    >>
    >>>> Bicycle wheel bearings, as most, require a slight preload so that under load, more than the one
    >>>> ball under the cone (inner race) is not carrying the entire load. [...]
    >>
    >>> Is that worded correctly?
    >>
    >> What part of that is unclear? Maybe when taken to the extreme, the
    >
    > I though he was querying if the cone was indeed the inner race.

    Inner meaning smaller radius. That's the only meaning of "inner" that is relevant in this context.

    --
    Benjamin Lewis

    "Love is a snowmobile racing across the tundra and then suddenly it flips over, pinning you
    underneath. At night, the ice weasels come." --Matt Groening
     
  10. A Muzi

    A Muzi Guest

    "trent gregory hill" <[email protected]> wrote in message
    news:p[email protected]u...
    > Folks,
    >
    > I know that you should check your hubs and overhaul them on a regular basis, but if you fail to do
    > so and discover, when you do get around to it, that the cones and / or hub shell have developed
    > pits, what would the consequences be, if any, of overhauling them as they are and continuing to
    > use them?
    >
    > Trent, who doesn't have any trashed hubs, but is curious about such things

    Depends.

    When changing a tire on an XMart bike, typically badly rusted and as devoid of grease as the day
    it left the store, I commonly open the hub, shoot in some grease and adjust as well as possible.
    Takes under one minute. I do this mostly because it is easier to check the tire's seating if the
    axle will spin in the hub so you can spin the wheel in midair. I completely ignore any pits in the
    cone. The white grease oozes out red from the powdered metal rust inside. But is it at least
    better after that.

    If it were my own nice vintage Campagnolo hubs ( horror!) I would replace the damaged cone (and
    the cup too if it were gouged out) and rebuild with new balls and fresh grease in a thoroughly
    clean hubshell.

    Somewhere inbetween, you'll need to decide how much expense and suffering you prefer.

    --
    Andrew Muzi http://www.yellowjersey.org Open every day since 1 April 1971
     
  11. Pete Biggs

    Pete Biggs Guest

    [email protected] wrote:

    > Subject: 8c.6 Wheel Bearing adjustment
    /snip
    > To test for proper adjustment, install the wheel and wiggle the rim side-to-side to determine that
    > there is no clearance (rattle), then let the wheel rotate freely to a stop, noting whether it
    > halts with a short (indexed) oscillation. If the wheel stops with an oscillating "shudder" at the
    > end of motion, bearing preload is too high.

    Some gaskets and weather boots can cause the wheel to stop suddenly with a shudder even when the
    bearings are loose.

    ~PB
     
  12. Karl Nelson

    Karl Nelson Guest

    [email protected] wrote in message news:<[email protected]>...
    > Trent Gregory Hill writes:
    >
    > > I know that you should check your hubs and overhaul them on a regular basis, but if you fail to
    > > do so and discover, when you do get around to it, that the cones and/or hub shell have developed
    > > pits, what would the consequences be, if any, of overhauling them as they are and continuing to
    > > use them?
    >
    > I think you are talking about cones and outer race and in these mainly the cone gets pitted
    > from use but mainly from overload. The FAQ item on this has been waiting a while to appear but
    > here it is:
    >
    > Subject: 8c.6 Wheel Bearing adjustment From: Jobst Brandt <[email protected]> Date:
    > Tue, 26 Nov 2002
    >

    I do not know whether the damage he refers to is from overload, but I would like to request that you
    answer assuming water damage, since this is something I have been wondering.

    I have damage to one side of a hub only, so clearly not a load problem. The grease was rust-colored,
    which made me suspect water.

    I would like to avoid replacing the hub for as long as possible, so how should I take care of it at
    this point? I have heard you say that nothing can be done to fix races, but can you continue to
    preserve them? Will there be a sudden or catastrophic failure at some point? I have also heard you
    say you carry extra balls to use in case of water damage. Can I gather that replacing the balls is
    good even if they go in a damaged hub?

    Thank you, Karl.
     
  13. Jobst Brandt

    Jobst Brandt Guest

    Pete Biggs <pLime{remove_fruit}@biggs.tc> writes:

    >> Subject: 8c.6 Wheel Bearing adjustment ... To test for proper adjustment, install the wheel and
    >> wiggle the rim side-to-side to determine that there is no clearance (rattle), then let the wheel
    >> rotate freely to a stop, noting whether it halts with a short (indexed) oscillation. If the wheel
    >> stops with an oscillating "shudder" at the end of motion, bearing preload is too high.

    > Some gaskets and weather boots can cause the wheel to stop suddenly with a shudder even when the
    > bearings are loose.

    I don't believe so. Boots and gaskets slide with viscous friction that has no detents as do ball
    bearings that are excessively preloaded. I don't think you could demonstrate such behavior with any
    reasonable hub on the market today. Maybe you could name such a product.

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

    Jobst Brandt Guest

    Karl Nelson writes:

    >>> I know that you should check your hubs and overhaul them on a regular basis, but if you fail to
    >>> do so and discover, when you do get around to it, that the cones and/or hub shell have developed
    >>> pits, what would the consequences be, if any, of overhauling them as they are and continuing to
    >>> use them?

    >> I think you are talking about cones and outer race and in these mainly the cone gets pitted
    >> from use but mainly from overload. The FAQ item on this has been waiting a while to appear but
    >> here it is:

    >> Subject: 8c.6 Wheel Bearing adjustment From: Jobst Brandt <[email protected]> Date:
    >> Tue, 26 Nov 2002 ...

    > I do not know whether the damage he refers to is from overload, but I would like to request that
    > you answer assuming water damage, since this is something I have been wondering.

    As Andrew Muzi mentioned, if it isn't an expensive hub, one for which replacement parts are
    available, just squirt some heavy oil in there and ride it. It will never be much good and with rust
    pits (that form around each ball contact when parked) they will only grow. Get new outer race, cone
    ands a set of bearing balls.

    > I have damage to one side of a hub only, so clearly not a load problem. The grease was
    > rust-colored, which made me suspect water.

    I don't know what is available for your hub. Mine (ancient Campagnolo) have spare bearing cups and
    cones. Bearing balls are available in most bicycle shops.

    > I have heard you say that nothing can be done to fix races, but can you continue to preserve them?

    There's not much you can do beyond what Andrew Muzi suggested unless you can get parts.

    > Will there be a sudden or catastrophic failure at some point? I have also heard you say you carry
    > extra balls to use in case of water damage. Can I gather that replacing the balls is good even if
    > they go in a damaged hub?

    It just gets harder to adjust as it wears and will have tight and loose areas. Nothing sudden. Even
    a cracked bearing ball will make a lot of noise and you put on the brakes and stop.

    Jobst Brandt [email protected] Palo Alto CA
     
  15. G.Daniels

    G.Daniels Guest

    trent! i change cones/bearings twice a year at about 5-6000miles or more year commuters mileage
    often with a 50+ lb. load on the back for 15+ miles at 20mph(downwind). I installed quality cones
    from wheels mfg as the standard generic replacements, 'standard tiwanese'?, go out of adjustment
    within a few-say 100 miles- and show pits and gouged bearing paths when open to see what's
    **))!^&&%%^&^ going on in there. still, the cones do wear quickly even with continuos maintenance to
    hold the lateral play down and JB's more bearings to contact/load support motion in. floated a few
    questions on more expensive hubs than shimano deore or ST using cartridge bearings as for touring
    across-Peru?-Staten Island?-or hauling the goods from superduper but no comments from long term
    users rather than boulevardiers.
     
  16. A Muzi

    A Muzi Guest

    "g.daniels" <[email protected]> wrote in message
    news:[email protected]...
    > trent! i change cones/bearings twice a year at about 5-6000miles or more year commuters mileage
    > often with a 50+ lb. load on the back for 15+ miles at 20mph(downwind). I installed quality cones
    > from wheels mfg as the standard generic replacements, 'standard tiwanese'?, go out of adjustment
    > within a few-say 100 miles- and show pits and gouged bearing paths when open to see what's
    > **))!^&&%%^&^ going on in there. still, the cones do wear quickly even with continuos maintenance
    > to hold the lateral play down and JB's more bearings to contact/load support motion in. floated a
    > few questions on more expensive hubs than shimano deore or ST using cartridge bearings as for
    > touring across-Peru?-Staten Island?-or hauling the goods from superduper but no comments from long
    > term users rather than boulevardiers.

    If you are experiencing "pits and gouged bearing paths" within " a few-say 100 miles" there is
    something awry with your technique .

    I did not understand most of your phrasing but I think you were implying that a "50+lb load" had
    some relevance to this problem. It does not.

    Wheels brand cones are as good as any, the problem does not lie there. Most Republic of China axle
    sets sold here (Jo You, King Kong, Sovos et al ) as aftermarket equipment are of useful quality - I
    don't see shoddy ones - so the pejorative "tiwanese" isn't appropriate, either.

    If I might venture a guess, are you using an excessive preload? That would result in a
    uniformly gouged bearing track, as opposed to a loose adjustment which would show wear on one
    side of the cone.

    Do you oil the axle threads and lock the cones against the locknuts securely on both sides? An axle
    set which isn't locked can auto-tighten against the bearing.
    --
    Andrew Muzi http://www.yellowjersey.org Open every day since 1 April 1971
     
  17. Jobst Brandt

    Jobst Brandt Guest

    Andrew Muzi writes:

    > If you are experiencing "pits and gouged bearing paths" within " a few-say 100 miles" there is
    > something awry with your technique.

    > I did not understand most of your phrasing but I think you were implying that a "50+lb load" had
    > some relevance to this problem. It does not.

    > Wheels brand cones are as good as any, the problem does not lie there. Most Republic of China axle
    > sets sold here (Jo You, King Kong, Sovos et al ) as aftermarket equipment are of useful quality -
    > I don't see shoddy ones - so the pejorative "Taiwanese" isn't appropriate, either.

    > If I might venture a guess, are you using an excessive preload? That would result in a
    > uniformly gouged bearing track, as opposed to a loose adjustment which would show wear on one
    > side of the cone.

    Properly hardened bearing races (cones and cups) do not gouge or plastically deform, they spall
    (break out in chips or flakes). If they develop depressed tracks, they are poor quality.

    > Do you oil the axle threads and lock the cones against the locknuts securely on both sides? An
    > axle set which isn't locked can auto-tighten against the bearing.

    I think this sort of detail doesn't help the user who is not mechanically adept at adjusting
    bearings. It's all hocus-pocus best left to the bicycle shop.

    Jobst Brandt [email protected] Palo Alto CA
     
  18. G.Daniels

    G.Daniels Guest

    1.load increases wear.dewdew. load increases wear.dewdew.
    2.bicycles are in general meanbt to sell and ride around the block. not haul the goods back from the
    grocery. that's touring.
    3.hauling stuff requires upgrades for:axles,cones,bearings,hubs,tires,spokes (DT) and the
    rider for sure.
    4.the cones: i have a cone collection!! from '80 on. early quality japanese cones are made from UFO
    steel similar to the shimano crank puller. filing UFO metal only ruins the file. harder than
    Wheels Mfg. seems the cone quality see 200,000mile toyota/volvo steel/machining, tails off as time
    moves toward us. the road experience, as opposed to the shop experience brings the quantification
    that harder cones give less "spallng"? it doesn't look like spalling to the naked eye. i associate
    spalling with talus and scree but the hills are grease free so far.
    4a. a racer friend sez the cone wear experienced commuting here is the result of dirt not metal
    insufficiency. the photos(possibly in a bike manual) of bearing wear I relate to on this hassle
    suggest "galling" but not "galling" due to dirt, that's a seperate photo example.
    5. adjustmnets at the axle? well, i follow your(plural) instructions and have packed bearings for
    thirty years without failure. frankly, producing significant extra wear through incorrect bearing
    adjustment should be evident to the beginner after the first try or two. no hocus pocus here just
    a careful playing of chopsticks meant to be ameliorative. ADJUSTING BEARINGS/CONES/AXLES
    PERFECTLYPERFECTLY IS NOT SHOP WORK ITS HOME MAINTENANCE. UPGRADE THE EQUIPMENT!! now what about
    the cartridge bearing ??????
     
  19. G.Daniels

    G.Daniels Guest

    after mulling this over- other sources suggest a touch of play at the axle after tightening all the
    nuts. this advice takes on the characteristics of a pandemic. how cum? could it be that preload
    works best with new regular surfaces and works not as well with worn irregular surfaces? since we
    have two eminent authoriies in AMUZI and J.Brandt proslytizing for preload, engineering studies on
    preload suggest that's the way to go. are there engineering studies suggesting that preload works
    well with irregular surfaces? not to throw smoke into this but consider worn cones and the
    corresponding(one hopes) diameter planes both facing forward perpendicular to the axle in the(one
    hopes) direction of vehicle movement. well, not exactly. if worn surfaces exist, the two(only maybe)
    diameter planes face in irregular directions and in rotation possibly wotk against each other with
    varying pressures maybe eating into the cone and bearing anduh hub surfaces?????????? or? the
    elliptical diameters(forced out of correspondence by thread pitch if nothing else, right?) line up
    and rotate together, balance themselves. wow, this i gotta see? on the other hand , i do preload
    crank's spindle and it wurks gud. reconciling that is presently unavailable. any cawment?
     
  20. G.Daniels

    G.Daniels Guest

    further, after getting back to the garage, occured to me that fondling the new deore lx hub i got
    thru the mail would evidence the desired preload?? this assumes that quality control at the shimano
    deore hub factory(which could be in lower slovenia?) is up to spec. also assumes that this preload
    is the preload JB and friends are suggesting? ANYWAY, the preload i have with this deore hub does
    bearing rumble lightly which is according to my experience, not necessarily by any means the truth
    in bearing adjustments(boy you said a mouthful) too much tightness by a few degrees. OR IS IT? a
    recently read authority, i forget where, suggests unscrewing the hubs as received as THIS preload by
    the factory is induced to qualify the assembley as being shippable and that the actual running
    preload will be less than the shipping OR the used a shipped preload will increase and accelerate
    wear there i asked for expert cawment on this but they're off somewhere else. the shipped preload,
    if defined by the authorities both for and against iza good bench mark for the do it
    yourselfur.always go down or up to the LBS and ask for a hub fondling session. fondle the deore then
    try the d uraace. if you live near AMUZi, go over and ask for an antiquo campy straight up.
     
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