Freehub vs Freewheel axles

Discussion in 'Cycling Equipment' started by Robert Taylor, Mar 24, 2003.

Thread Status:
Not open for further replies.
  1. One of the articles of faith that we see repeated over and over is the statement that (other things
    being the same) the axle is less likely to break in a freehub because the bearings are further
    outboard thus reducing the length of unsupported axle. I submit that the length of unsupported axle
    is reduced ONLY ON THE DRIVE SIDE. There is a bunch of unsupported axle on the non-drive side
    especially in the case of really wide OLN tandem hubs (145mm to 160mm). I think the optimm tandem
    rear hub would be constructed to provide zero dish which would most likely mean that there would be
    as much unsuported axle on the non-drive side of a cassette hub as there would be on the drive side
    of a freewheel hub. Granted the freehub would have less unsupported axle on the drive side.

    Hubs could be made to reduce the unsupported axle length on the non-drive side by moving the bearing
    outside the spoke flange on the non-drive side. Since to my knowledge no manufacturer bothers to do
    this even on tandem hubs of extreme width it leads me to think that perhaps the length of
    unsupported axle is of less importance than quoted wisdom would suggest.

    My 1985 Santana tandem has a dishless freewheel rear wheel and in all that time it has had no
    broken axles.

    Bob Taylor
     
    Tags:


  2. Robert Taylor wrote:

    > One of the articles of faith that we see repeated over and over is the statement that (other
    > things being the same) the axle is less likely to=

    > break in a freehub because the bearings are further outboard thus reducing the length of
    > unsupported axle. I submit that the length of unsupported axle is reduced ONLY ON THE DRIVE SIDE.
    > There is a bunch o=
    f
    > unsupported axle on the non-drive side especially in the case of really=

    > wide OLN tandem hubs (145mm to 160mm).=20

    That's true, but the chain pull, which is the largest force acting on=20 the axle, is basically only
    stressing the right side.

    > I think the optimm tandem rear hub would be constructed to provide zero dish which would most
    > likely mean that there would be as much unsuported axle on the non-drive side of a cassette hub as
    > there would be on the drive side of a freewheel hub. Granted the freehub would have less
    > unsupported axle on the drive=

    > side. =20
    >=20
    > Hubs could be made to reduce the unsupported axle length on the non-drive side by moving the
    > bearing outside the spoke flange on the non-drive side. =20

    They could, but this would be a "solution in search of a problem" since=20 the left side never
    bends/breaks.

    > Since to my knowledge no manufacturer bothers to do this even on tandem hubs of extreme width it
    > leads me to think that perhaps the length of unsupported axle is of less importance than quote=
    d
    > wisdom would suggest.

    That is true as far as the left side is concerned, because of the much=20 lower stresses experienced
    by the left side.

    Sheldon "It's The Chain Pull, Not The Weight Load" Brown
    +----------------------------------------------------+
    | I=92m not convinced that this was the right time | to attack Iraq, but I would like to express
    | my | support for, and gratitude to U.S. and allied | fighting forces, and to wish them all
    | success. |
    +----------------------------------------------------+ Harris Cyclery, West Newton, Massachusetts
    Phone 617-244-9772 FAX 617-244-1041 http://harriscyclery.com Hard-to-find parts shipped Worldwide
    http://captainbike.com http://sheldonbrown.com
     
  3. I've just realized that I didn't word something too well when I was talking about moving the
    non-drive side bearing outside the spoke flange. That bearing is of course outside the flange but
    only just. The point I wanted to make was that it could be moved as far outboard of the spoke flange
    as the bearing on the drive side but no manufacturer bothers to do it so maybe that length of
    unsupported axle isn't as deadly as it's so often said to be.

    Also in anticipation, yes it is true that a freehub will still have less usupported axle width in
    total (drive side+non drive side) which is almost certainly a good thing. I'm just not convinced
    that it is a critical thing.

    Bob Taylor
     
  4. In article <[email protected]>, Robert Taylor
    <[email protected]> wrote:
    >One of the articles of faith that we see repeated over and over is the statement that (other things
    >being the same) the axle is less likely to break in a freehub because the bearings are further
    >outboard thus reducing the length of unsupported axle.

    I don't think it is an article of faith - it is an empirical observation you tend to hear from
    people who have fixed lots of broken axles.

    > I submit that the length of unsupported axle is reduced ONLY ON THE DRIVE SIDE.

    But why should I care about the unsupported axle on the left side when people don't break it there?
    Nothing to fix! Say, maybe that means we should make the axle a little thinner on the left side...

    I can't name a single axle I have ever seen broken on the left side. I'm sure it's possible but it
    is not a normal occurrance. Broken axle on the drive side however is quite a common thing,
    especially for low quality mild steel axles which break at the drive side cone, and respaced hubs
    that have extra dish to accommodate 8-speed freewheel width.

    --Paul
     
  5. Jon Isaacs

    Jon Isaacs Guest

    >The point I wanted to make was that it could be moved as far outboard of the spoke flange as the
    >bearing on the drive side but no manufacturer bothers to do it so maybe that length of unsupported
    >axle isn't as deadly as it's so often said to be.

    >
    >Also in anticipation, yes it is true that a freehub will still have less usupported axle width in
    >total (drive side+non drive side) which is almost certainly a good thing. I'm just not convinced
    >that it is a critical thing.

    For us big fellows who rode 6 and 7 speed freewheel designs, it is a critical thing. Those old hubs
    bent plenty of axles.

    While it may be possible to get by with more overhang than there is with Shimano freehub, there is
    no reason to.

    jon isaacs
     
  6. Bluto

    Bluto Guest

    [email protected] (Robert Taylor) wrote:

    > One of the articles of faith that we see repeated over and over is the statement that (other
    > things being the same) the axle is less likely to break in a freehub because the bearings are
    > further outboard thus reducing the length of unsupported axle. I submit that the length of
    > unsupported axle is reduced ONLY ON THE DRIVE SIDE. There is a bunch of unsupported axle on the
    > non-drive side especially in the case of really wide OLN tandem hubs (145mm to 160mm).

    Another fact conveniently overlooked by those who praise cassette hubs is that such hubs are limited
    to the use of only externally threaded axles with a maximum diameter of 10mm. That is to say, the
    weakest type of rear axle is the only type of rear axle you can use with a cassette hub.

    Freewheel hubs are able to use axles as large as 19mm, the limitation being the inside diameter of a
    splined freewheel removing tool. Since freewheel hubs can be made to use sealed cartridge bearings,
    there is no need to provide preload adjustment, and the axle can be smooth on the outside. The
    absence of external threads allows the axle to be much stronger in any given size and material.

    Chalo Colina
     
  7. Bruce Lange

    Bruce Lange Guest

    Hey Bluto,

    Can you recommend a 14mm BMX hub that will accept road freewheels, and take slotted axles (to fit
    road dropouts)?

    I bought an Odyssey Hazard with this idea in mind, but it's large locknut gets in the way of a
    multi-speed freewheel going on there. Do certain brands of freewheels have more clearance? Also, I'm
    not sure which sealed bearing hubs make an accompanying slotted axle (that will be not-threaded in
    the right places).

    And hey, don't Phil cassette hubs have a 15mm axle? Not exactly affordable, but there.

    Thanks,

    Bruce

    > Another fact conveniently overlooked by those who praise cassette hubs is that such hubs are
    > limited to the use of only externally threaded axles with a maximum diameter of 10mm. That is to
    > say, the weakest type of rear axle is the only type of rear axle you can use with a cassette hub.
    >
    > Freewheel hubs are able to use axles as large as 19mm, the limitation being the inside diameter of
    > a splined freewheel removing tool. Since freewheel hubs can be made to use sealed cartridge
    > bearings, there is no need to provide preload adjustment, and the axle can be smooth on the
    > outside. The absence of external threads allows the axle to be much stronger in any given size and
    > material.
    >
    > Chalo Colina
     
  8. Chalo Colina wrote:

    > Another fact conveniently overlooked by those who praise cassette hubs is that such hubs are
    > limited to the use of only externally threaded axles with a maximum diameter of 10mm. That is to
    > say, the weakest type of rear axle is the only type of rear axle you can use with a cassette hub.

    That's as may be, but in practice, axle failures in cassette Freehubs are virtually unknown, so
    there's no need to make them thicker!

    If I replaced the wooden legs of my kitchen table with a solid reinforced concrete pedestal, the
    table would be much stronger, probably able to sustain loads of several tons. However, since I went
    on my diet, I rarely load the table with more than half a ton of food, so the wooden legs are more
    than adequate.

    Sheldon "Enough Is Enough" Brown +---------------------------------------+
    | Whatever became of eternal truth? |
    +---------------------------------------+ Harris Cyclery, West Newton, Massachusetts Phone
    617-244-9772 FAX 617-244-1041 http://harriscyclery.com Hard-to-find parts shipped Worldwide
    http://captainbike.com http://sheldonbrown.com
     
  9. Kinkycowboy

    Kinkycowboy Guest

    On 24 Mar 2003 17:48:30 -0800, [email protected] (Bluto) wrote:

    >[email protected] (Robert Taylor) wrote:
    >
    >> One of the articles of faith that we see repeated over and over is the statement that (other
    >> things being the same) the axle is less likely to break in a freehub because the bearings are
    >> further outboard thus reducing the length of unsupported axle. I submit that the length of
    >> unsupported axle is reduced ONLY ON THE DRIVE SIDE. There is a bunch of unsupported axle on the
    >> non-drive side especially in the case of really wide OLN tandem hubs (145mm to 160mm).
    >
    >Another fact conveniently overlooked by those who praise cassette hubs is that such hubs are
    >limited to the use of only externally threaded axles with a maximum diameter of 10mm. That is to
    >say, the weakest type of rear axle is the only type of rear axle you can use with a cassette hub.
    >
    >Freewheel hubs are able to use axles as large as 19mm, the limitation being the inside diameter of
    >a splined freewheel removing tool. Since freewheel hubs can be made to use sealed cartridge
    >bearings, there is no need to provide preload adjustment, and the axle can be smooth on the
    >outside. The absence of external threads allows the axle to be much stronger in any given size and
    >material.
    >
    >Chalo Colina

    Shimano Freehubs limit one to a 10mm axle because they bolt the freewheel assembly to the hub shell
    with a 10mm a/f hex key. The 10mm restriction is not inherent in the freehub idea, and lots of
    manufacturers use bigger axles, eg 19.5mm Chris King, any 12mm bolt through DH hub. It is also
    possible to put the bearings right next to the dropouts, and even to put another bearing at the
    flange position too, there are 3 and 4 bearing hubs out there; my Joytech singlespeed disc hub is
    just one example. But, as everybody else has already pointed out, a 2 bearing freeehub with the
    driveside bearing under the 3rd sprocket and the non drive side bearing just outside the flange, and
    with a 10mm threaded axle, has proven to be adequate for solo road and XC bikes, which are the high
    volume classes Shimano is interested
    in. Freeriders, downhillers, dirt jumpers and tandemists who find 10mm axles a problem are well
    catered for by specialist manufacturers.

    Kinky Cowboy

    *Your milage may vary Batteries not included May contain traces of nuts.
     
  10. Bluto

    Bluto Guest

    "Bruce Lange" <[email protected]> wrote:

    > Hey Bluto,
    >
    > Can you recommend a 14mm BMX hub that will accept road freewheels, and take slotted axles (to fit
    > road dropouts)?
    >
    > I bought an Odyssey Hazard with this idea in mind, but it's large locknut gets in the way of a
    > multi-speed freewheel going on there. Do certain brands of freewheels have more clearance? Also,
    > I'm not sure which sealed bearing hubs make an accompanying slotted axle (that will be
    > not-threaded in the right places).

    I have run into this issue before, and resolved it in one of two ways:

    1) Turn or grind the too-large locknut to an acceptable size.

    2) Make my own axle assembly (still easier than making my own hub).

    The quick-n-dirty way to get that locknut down to size is to affix it to an axle, affix the axle
    to a drill, and spin the sucker while holding it against a bench grinder. Since many hand drills
    max out at
    3.7mm,using a 1/2" flat head bolt with a 1/2" nut to bind the locknut up against the tapered
    underside of the head might be a better approach.

    The tasty way to solve the problem is to make a stepped shaft
    3i(1/4") on the freewheel side end and 15mm through both bearings. Put a M14x1 thread on the left
    end only as far as the locknut protrudes and no farther. Drill and tap both ends M8x1.25. Make
    a tubular sleeve that corresponds to the width separating the inner bearings. Install this axle
    and use 8mm bolts and washers to fix the axle in the frame.

    Chalo Colina
     
  11. Jt

    Jt Guest

    "KinkyCowboy" <[email protected]> wrote in message
    news:[email protected]...
    > Shimano Freehubs limit one to a 10mm axle because they bolt the freewheel assembly to the hub
    > shell with a 10mm a/f hex key. The 10mm restriction is not inherent in the freehub idea, and lots
    > of manufacturers use bigger axles, eg 19.5mm Chris King, any 12mm bolt through DH hub. It is also
    > possible to put the bearings right next to the dropouts, and even to put another bearing at the
    > flange position too, there are 3 and 4 bearing hubs out there; my Joytech singlespeed disc hub is
    > just one example. But, as everybody else has already pointed out, a 2 bearing freeehub with the
    > driveside bearing under the 3rd sprocket and the non drive side bearing just outside the flange,
    > and with a 10mm threaded axle, has proven to be adequate for solo road and XC bikes, which are the
    > high volume classes Shimano is interested
    > in. Freeriders, downhillers, dirt jumpers and tandemists who find 10mm axles a problem are well
    > catered for by specialist manufacturers.

    The bearings are in the wrong place to start with. They should be mounted in the frame.
     
Loading...
Thread Status:
Not open for further replies.
Loading...