Rear bearing 'hum' on corners. Cause?

Discussion in 'Cycling Equipment' started by Thomas Burns, Jun 3, 2003.

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  1. Thomas Burns

    Thomas Burns Guest

    I recently picked up a Trek 820 for a song that needed only a moderate amount of work to get into
    shape, and the only outstanding issue (besides a frustratingly persistent front brake squeal!) is a
    prominent humming of the rear wheel when cornering. I suspect it's the bearings, and would like
    input on whether all they need is a clean and repack, or is this a sign of more extensive wear and I
    should replace the bearings, cones, etc? There is a slight amount of play in the wheel, so it does
    need a cone adjustment. When riding on straightaways, there is no noticeable noise at all from the
    bearings - only when cornering.

    t
    --
    Thomas Burns thrshr @@ hotmail
     
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  2. A Muzi

    A Muzi Guest

    "Thomas Burns" <[email protected]> wrote in message
    news:[email protected]...
    > I recently picked up a Trek 820 for a song that needed only a moderate amount of work to get into
    > shape, and the only outstanding issue (besides
    a
    > frustratingly persistent front brake squeal!) is a prominent humming of
    the
    > rear wheel when cornering. I suspect it's the bearings, and would like input on whether all they
    > need is a clean and repack, or is this a sign of more extensive wear and I should replace the
    > bearings, cones, etc? There
    is
    > a slight amount of play in the wheel, so it does need a cone adjustment. When riding on
    > straightaways, there is no noticeable noise at all from the bearings - only when cornering.
    >
    > t
    > --

    Remove the wheel and see if it's a broken axle - sounds like that.

    --
    Andrew Muzi http://www.yellowjersey.org Open every day since 1 April 1971
     
  3. G Huang

    G Huang Guest

    Thomas Burns wrote:
    > I recently picked up a Trek 820 for a song that needed only a moderate amount of work to get into
    > shape, and the only outstanding issue (besides a frustratingly persistent front brake squeal!) is
    > a prominent humming of the rear wheel when cornering. I suspect it's the bearings, and would like
    > input on whether all they need is a clean and repack, or is this a sign of more extensive wear and
    > I should replace the bearings, cones, etc? There is a slight amount of play in the wheel, so it
    > does need a cone adjustment. When riding on straightaways, there is no noticeable noise at all
    > from the bearings - only when cornering.

    Could it be that the tire is more knobby on the sides than the center?

    GH
     
  4. Thomas Burns

    Thomas Burns Guest

    "G Huang" <[email protected]_bell-labs.com> wrote in message
    news:[email protected]_bell-labs.com...
    >
    > Thomas Burns wrote:
    > > I recently picked up a Trek 820 for a song that needed only a moderate amount of work to get
    > > into shape, and the only outstanding issue
    (besides a
    > > frustratingly persistent front brake squeal!) is a prominent humming of
    the
    > > rear wheel when cornering. I suspect it's the bearings, and would like input on whether all they
    > > need is a clean and repack, or is this a sign
    of
    > > more extensive wear and I should replace the bearings, cones, etc?
    There is
    > > a slight amount of play in the wheel, so it does need a cone adjustment. When riding on
    > > straightaways, there is no noticeable noise at all from
    the
    > > bearings - only when cornering.
    >
    > Could it be that the tire is more knobby on the sides than the center?

    I don't think this is it, though it's an option that never crossed my mind. The hum is a definite
    hum that increases the tighter the turn, rather than the more rumbly road noise you get from the
    tire. An excellent low-tech suggestion, though.

    t
     
  5. Thomas Burns

    Thomas Burns Guest

    "A Muzi" <[email protected]> wrote in message news:[email protected]...
    > "Thomas Burns" <[email protected]> wrote in message
    > news:[email protected]...
    > > I recently picked up a Trek 820 for a song that needed only a moderate amount of work to get
    > > into shape, and the only outstanding issue
    (besides
    > a
    > > frustratingly persistent front brake squeal!) is a prominent humming of
    > the
    > > rear wheel when cornering. I suspect it's the bearings, and would like input on whether all they
    > > need is a clean and repack, or is this a sign
    of
    > > more extensive wear and I should replace the bearings, cones, etc?
    There
    > is
    > > a slight amount of play in the wheel, so it does need a cone adjustment. When riding on
    > > straightaways, there is no noticeable noise at all from
    the
    > > bearings - only when cornering.
    > >
    > > t
    > > --
    >
    > Remove the wheel and see if it's a broken axle - sounds like that.

    This makes sense. I planned on pulling it all apart in any case, but since I'm in the process of
    rebuilding a bike for one of my other sons I was going to put this off until later. But if the axle
    is broken I should probably do that one first (or keep it off limits). I already adjusted the cones
    to remove some play in the wheel, and after a brief ride some play reappeared. I originally thought
    it was my novice skills, but something tells me a broken axle might behave this way also.

    t
     
  6. Robin Hubert

    Robin Hubert Guest

    "Thomas Burns" <[email protected]> wrote in message
    news:[email protected]...
    >
    > "A Muzi" <[email protected]> wrote in message news:[email protected]...
    > > "Thomas Burns" <[email protected]> wrote in message
    > > news:[email protected]...
    > > > I recently picked up a Trek 820 for a song that needed only a moderate amount of work to get
    > > > into shape, and the only outstanding issue
    > (besides
    > > a
    > > > frustratingly persistent front brake squeal!) is a prominent humming
    of
    > > the
    > > > rear wheel when cornering. I suspect it's the bearings, and would
    like
    > > > input on whether all they need is a clean and repack, or is this a
    sign
    > of
    > > > more extensive wear and I should replace the bearings, cones, etc?
    > There
    > > is
    > > > a slight amount of play in the wheel, so it does need a cone
    adjustment.
    > > > When riding on straightaways, there is no noticeable noise at all from
    > the
    > > > bearings - only when cornering.
    > > >
    > > > t
    > > > --
    > >
    > > Remove the wheel and see if it's a broken axle - sounds like that.
    >
    > This makes sense. I planned on pulling it all apart in any case, but
    since
    > I'm in the process of rebuilding a bike for one of my other sons I was
    going
    > to put this off until later. But if the axle is broken I should probably
    do
    > that one first (or keep it off limits). I already adjusted the cones to remove some play in the
    > wheel, and after a brief ride some play
    reappeared.
    > I originally thought it was my novice skills, but something tells me a broken axle might behave
    > this way also.
    >

    Yeah, but you couldn't have adjusted your cones if the axle is broken.

    --
    Robin Hubert <[email protected]
     
  7. Jim Adney

    Jim Adney Guest

    On 03 Jun 2003 20:53:37 GMT "Thomas Burns" <[email protected]> wrote:

    >I recently picked up a Trek 820 for a song that needed only a moderate amount of work to get into
    >shape, and the only outstanding issue (besides a frustratingly persistent front brake squeal!) is a
    >prominent humming of the rear wheel when cornering. I suspect it's the bearings, and would like
    >input on whether all they need is a clean and repack, or is this a sign of more extensive wear and
    >I should replace the bearings, cones, etc? There is a slight amount of play in the wheel, so it
    >does need a cone adjustment. When riding on straightaways, there is no noticeable noise at all from
    >the bearings - only when cornering.

    If there really is a noise that you can hear only while cornering, I suspect that it is coming from
    the tires. It is likely that in leaning, you are rolling on an unworn part of the tread that has
    slightly different contours.

    The bearings don't get sideload when you corner. The lean that you do naturally keeps the forces
    "straight down" for the wheels and bearings. The direction does not change significantly, but the
    magnitude of the force does increase as the lean becomes more extreme. Still, it would be quite
    unusual to actually be able hear noise from the bearings.

    -
    -----------------------------------------------
    Jim Adney [email protected] Madison, WI 53711 USA
    -----------------------------------------------
     
  8. David Kunz

    David Kunz Guest

    Jim Adney wrote:
    > On 03 Jun 2003 20:53:37 GMT "Thomas Burns" <[email protected]> wrote:
    >
    >
    >>I recently picked up a Trek 820 for a song that needed only a moderate amount of work to get into
    >>shape, and the only outstanding issue (besides a frustratingly persistent front brake squeal!) is
    >>a prominent humming of the rear wheel when cornering. I suspect it's the bearings, and would like
    >>input on whether all they need is a clean and repack, or is this a sign of more extensive wear and
    >>I should replace the bearings, cones, etc? There is a slight amount of play in the wheel, so it
    >>does need a cone adjustment. When riding on straightaways, there is no noticeable noise at all
    >>from the bearings - only when cornering.
    >
    >
    > If there really is a noise that you can hear only while cornering, I suspect that it is coming
    > from the tires. It is likely that in leaning, you are rolling on an unworn part of the tread that
    > has slightly different contours.
    >
    > The bearings don't get sideload when you corner. The lean that you do naturally keeps the forces
    > "straight down" for the wheels and bearings. The direction does not change significantly, but the
    > magnitude of the force does increase as the lean becomes more extreme. Still, it would be quite
    > unusual to actually be able hear noise from the bearings.

    I've had the flex of hard cornering cause disc rotors to slightly hit the pads and v-brakes to
    slightly hit the rims. Could it be this?

    David
     
  9. My tires make a different sound when I corner as well, and it does increase the harder I'm leaning.

    Remember, when you round a corner the tires are not simply rolloing any more, there are shear forces
    working on the rubber as well, and these could very likely affect their "song".

    May you have the wind at your back. And a really low gear for the hills! Chris

    Chris'Z Corner "The Website for the Common Bicyclist": http://www.geocities.com/czcorner
     
  10. Ns>

    Ns> Guest

    I know most Trek's have shimano on them, but I have had a problem after a major overhaul at a LBS
    (tools were stolen:-( ) where Campy Record Road rear hub was built with identical bearings on each
    side, but, the bearings are not supposed to be the same size... I got a new hub out of
    it... But that could be the cause as well if you are using Campy hubs...

    Also depending on the age of the bike, (if it has a freewheel) the Freewheel could need greasing
    badly, if powering in and out of the corners hard it may make a gravelly (for lack of the right
    word) sound.

    My2c, NS
     
  11. Thomas Burns

    Thomas Burns Guest

    I wrote in message news:[email protected]...
    > I recently picked up a Trek 820 for a song that needed only a moderate amount of work to get into
    > shape, and the only outstanding issue (besides
    a
    > frustratingly persistent front brake squeal!) is a prominent humming of
    the
    > rear wheel when cornering. I suspect it's the bearings, and would like input on whether all they
    > need is a clean and repack, or is this a sign of more extensive wear and I should replace the
    > bearings, cones, etc?

    First off, thanks to all for your various suggestions. I was on the verge of taking everything apart
    when I went for one more test ride and found the problem to have an almost embarrasingly simple
    cause. It turns out the vibrations from the knobbies on turns caused the reflector in the spokes to
    also vibrate. The reflector had slid closer to the hub so that it was no longer held snugly by the
    spokes. The reflector vibrated against the spokes, resulting in the hum that I was hearing (which
    had a distinctly different tone from the hum of the tires).

    Once I figured it out, I laughed and felt quite stooopid at the same time. At least it's one less
    hub I need to overhaul.

    t
     
  12. Glad you found the answer, and that it was something simple (read: harmless).

    Do overhaul your hubs every now and then, though ;-3)

    May you have the wind at your back. And a really low gear for the hills! Chris

    Chris'Z Corner "The Website for the Common Bicyclist": http://www.geocities.com/czcorner
     
  13. David Kunz

    David Kunz Guest

    Thomas Burns wrote:
    > I wrote in message news:[email protected]...
    >
    >>I recently picked up a Trek 820 for a song that needed only a moderate amount of work to get into
    >>shape, and the only outstanding issue (besides
    >
    > a
    >
    >>frustratingly persistent front brake squeal!) is a prominent humming of
    >
    > the
    >
    >>rear wheel when cornering. I suspect it's the bearings, and would like input on whether all they
    >>need is a clean and repack, or is this a sign of more extensive wear and I should replace the
    >>bearings, cones, etc?
    >
    >
    > First off, thanks to all for your various suggestions. I was on the verge of taking everything
    > apart when I went for one more test ride and found the problem to have an almost embarrasingly
    > simple cause. It turns out the vibrations from the knobbies on turns caused the reflector in the
    > spokes to also vibrate. The reflector had slid closer to the hub so that it was no longer held
    > snugly by the spokes. The reflector vibrated against the spokes, resulting in the hum that I was
    > hearing (which had a distinctly different tone from the hum of the tires).
    >
    > Once I figured it out, I laughed and felt quite stooopid at the same time. At least it's one less
    > hub I need to overhaul.
    >
    > t
    >
    >

    Believe it on not, I had the same thing happen -- I had just forgotten about it.

    David
     
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