Load-bearing part of axle?

Discussion in 'Cycling Equipment' started by Song, Mar 1, 2004.

  1. Song

    Song Guest

    Just curious as to exactly which part of the wheel axle bears the load of the bike. Several threads
    on rear hubs have indicated that the part of the axle beyond the locknuts does not bear load. So is
    it that the skewer nuts and locknuts bear the load through friction in the vertical plane?

    thanks Song
     
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  2. Ron Hardin

    Ron Hardin Guest

    Song wrote:
    >
    > Just curious as to exactly which part of the wheel axle bears the load of the bike. Several
    > threads on rear hubs have indicated that the part of the axle beyond the locknuts does not
    > bear load. So is it that the skewer nuts and locknuts bear the load through friction in the
    > vertical plane?
    >
    > thanks Song

    My axles always broke (when they used to break) just inside the cone on the driven side, for what
    that's worth. The axle saw the load as coming from the wheel, not the frame, as far as strength
    requirement was concerned.

    Turn your picture over and you have a beam supporting two interior weights (from the wheel) problem,
    where does it break? In the middle, which is where the cone in question is.
    --
    Ron Hardin [email protected]

    On the internet, nobody knows you're a jerk.
     
  3. Dvt

    Dvt Guest

    Song wrote:

    > Just curious as to exactly which part of the wheel axle bears the load of the bike. Several
    > threads on rear hubs have indicated that the part of the axle beyond the locknuts does not
    > bear load. So is it that the skewer nuts and locknuts bear the load through friction in the
    > vertical plane?

    With a well-tensioned skewer, the answer is yes. You can cut the axle flush at the locknuts and the
    wheel will stay in place.

    Two things to look at/think about. Sheldon Brown, on one of his fixie pages at sheldonbrown.com, has
    done just what I mentioned above. At last check he hadn't reported any problems.

    The second thing to consider is horizontal dropouts. The chain tries to pull the wheel forward when
    you pedal. If the skewer is properly tightened, the axle does not slide within that horizontal slot.
    Those forward forces can be much greater than the forces due to gravity. Since the axle is not
    bearing on the dropout, the friction of the locknut and skewer are holding it in place.

    I have at least one rear wheel that has very little or no axle beyond the locknuts. I don't even
    recall which wheel it is at the moment, but I remember doing it a few years back. No problems yet.

    --
    Dave dvt at psu dot edu
     
  4. ZeeExSixAre

    ZeeExSixAre Guest

    > With a well-tensioned skewer, the answer is yes. You can cut the axle flush at the locknuts and
    > the wheel will stay in place.

    I do not believe this is always the case.

    In trials riding, there are often jumps in which many lbs of force are exerted on the bike.

    My friend's cromo PlanetX frame with 8mm thick dropouts completely obliterated the threads on the
    axle of an XT disc hub. I believe the axle might have been cut off so that it could be replaced with
    another one. He puts his QR on so tight, the LBS has to use tools to get it off. He was advised in
    the future not to put it on so tight, both to prevent the nut on the QR from popping off, and also
    to prevent overly-preloaded bearings.

    Why did the axle become flattened? If locknut friction is the sole provider of vertical force, then
    there should be zero (or very slight) force on the axle. Flattened axle threads are an obvious
    indicator of severe forces...

    --
    Phil, Squid-in-Training
     
  5. Song

    Song Guest

    Ah. I guess I should have said that my intended context is road riding, perhaps lightly loaded
    touring. I can definitely see how trials riding could be a very different affair...

    Song

    "ZeeExSixAre" <[email protected]> wrote in message
    news:[email protected]...
    > > With a well-tensioned skewer, the answer is yes. You can cut the axle flush at the locknuts and
    > > the wheel will stay in place.
    >
    > I do not believe this is always the case.
    >
    > In trials riding, there are often jumps in which many lbs of force are exerted on the bike.
    >
    > My friend's cromo PlanetX frame with 8mm thick dropouts completely obliterated the threads on the
    > axle of an XT disc hub. I believe the axle might have been cut off so that it could be replaced
    > with another one. He puts his QR on so tight, the LBS has to use tools to get it off. He was
    > advised in the future not to put it on so tight, both to prevent the nut
    on
    > the QR from popping off, and also to prevent overly-preloaded bearings.
    >
    > Why did the axle become flattened? If locknut friction is the sole
    provider
    > of vertical force, then there should be zero (or very slight) force on the axle. Flattened axle
    > threads are an obvious indicator of severe forces...
    >
    > --
    > Phil, Squid-in-Training
     
  6. ZeeExSixAre

    ZeeExSixAre Guest

    "Song" <[email protected]> wrote in message
    news:[email protected]...
    > Ah. I guess I should have said that my intended context is road riding, perhaps lightly loaded
    > touring. I can definitely see how trials riding
    could
    > be a very different affair...

    Whew, okay. I thought you were implying all riding. Then I agree on all points.

    --
    Phil, Squid-in-Training
     
  7. Dvt

    Dvt Guest

    ZeeExSixAre wrote:
    >>With a well-tensioned skewer, the answer is yes. You can cut the axle flush at the locknuts and
    >>the wheel will stay in place.

    > I do not believe this is always the case.
    >
    > In trials riding, there are often jumps in which many lbs of force are exerted on the bike.

    Sorry, I didn't consider the extreme cases of abuse. :)

    --
    Dave dvt at psu dot edu
     
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