Rear dropout OLN measurement

Discussion in 'UK and Europe' started by Chesney Christ, Feb 5, 2003.

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  1. Hi all,

    Thinking again of getting new wheels, and have been vexing over the OLN size. Am I correct in
    thinking that the correct rear OLN measurement may be obtained by measuring the distance between the
    two inside edges of the rear dropouts ?

    Seems that I have 130mm OLN, which is good. But apparently rather unusual, as the bike came with a 7
    speed gears (on a freewheel) ..

    --
    George H.W. Bush, as Presidential Nominee for the Republican party; 1987-AUG-27: "No, I don't know
    that Atheists should be considered as citizens, nor should they be considered as patriots. This is
    one nation under God."
     
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  2. Pete Biggs

    Pete Biggs Guest

    Chesney Christ wrote:
    > Thinking again of getting new wheels, and have been vexing over the OLN size. Am I correct in
    > thinking that the correct rear OLN measurement may be obtained by measuring the distance between
    > the two inside edges of the rear dropouts ?

    That's the idea, but it may not always actually be exactly what it's supposed to be......

    > Seems that I have 130mm OLN, which is good. But apparently rather unusual, as the bike came with a
    > 7 speed gears (on a freewheel) ..

    Some MTB 7sps were/are 130mm. See: http://www.sheldonbrown.com/gloss_sp-ss.html#spacing

    ~PB
     
  3. Chris French

    Chris French Guest

    In message <[email protected]>, Chesney Christ <[email protected]> writes
    >
    >Hi all,
    >
    >Thinking again of getting new wheels, and have been vexing over the OLN size. Am I correct in
    >thinking that the correct rear OLN measurement may be obtained by measuring the distance between
    >the two inside edges of the rear dropouts ?
    >
    Yep.

    >Seems that I have 130mm OLN, which is good. But apparently rather unusual, as the bike came with a
    >7 speed gears (on a freewheel) ..
    >
    Is that unusual? You don't say what the bike is 'road' bikes tend normally have 130mm OLN even
    nowadays with a zillion sprockets and have done so for some time.
    --
    Chris French, Leeds
     
  4. A certain chris French, of uk.rec.cycling "fame", writes :

    >>Seems that I have 130mm OLN, which is good. But apparently rather unusual, as the bike came with a
    >>7 speed gears (on a freewheel) ..
    >>
    >Is that unusual? You don't say what the bike is 'road' bikes tend normally have 130mm OLN even
    >nowadays with a zillion sprockets and have done so for some time.

    This is a Dawes Giro 200 from two years ago (road bike).

    Apparently 126mm is the common size for a 7 speed road bike, going by ol' Sheldon's site. I guess my
    bike comes from the time when 7 speeds were already fading into obscurity :)

    --
    George H.W. Bush, as Presidential Nominee for the Republican party; 1987-AUG-27: "No, I don't know
    that Atheists should be considered as citizens, nor should they be considered as patriots. This is
    one nation under God."
     
  5. Tony W

    Tony W Guest

    "Chesney Christ" <[email protected]> wrote in message
    news:[email protected]...

    > Thinking again of getting new wheels, and have been vexing over the OLN size. Am I correct in
    > thinking that the correct rear OLN measurement may be obtained by measuring the distance between
    > the two inside edges of the rear dropouts ?
    >
    > Seems that I have 130mm OLN, which is good. But apparently rather unusual, as the bike came with a
    > 7 speed gears (on a freewheel) ..

    I think its outside edges -- but wait for confirmation from an expert.

    Surprisingly, my ancient Galaxy (with a 6 speed freewheel) is 130mm (by my definition -- would be
    even more by yours).

    Yes, I am thinking of an up-grade too :)

    T
     
  6. A certain Tony W, of uk.rec.cycling "fame", writes :
    >
    >"Chesney Christ" <[email protected]> wrote in message
    >news:[email protected]...
    >
    >> Thinking again of getting new wheels, and have been vexing over the OLN size. Am I correct in
    >> thinking that the correct rear OLN measurement may be obtained by measuring the distance between
    >> the two inside edges of the rear dropouts ?
    >>
    >> Seems that I have 130mm OLN, which is good. But apparently rather unusual, as the bike came with
    >> a 7 speed gears (on a freewheel) ..
    >
    >I think its outside edges -- but wait for confirmation from an expert.

    Sheldon says :

    "The distance between the outermost locknuts of a conventional hub axle, or whatever equivalent
    parts fit against the inside surfaces of the fork ends of a frame. They must match the spacing (see
    chart) of the frame that the wheels are to be installed in. "

    It's the locknuts on mine that press against the inside edges whenever the quick-release is
    tightened.

    --
    George H.W. Bush, as Presidential Nominee for the Republican party; 1987-AUG-27: "No, I don't know
    that Atheists should be considered as citizens, nor should they be considered as patriots. This is
    one nation under God."
     
  7. Tony W

    Tony W Guest

    "Chesney Christ" <[email protected]> wrote in message
    news:[email protected]...
    >
    > Sheldon says :
    >
    > "The distance between the outermost locknuts of a conventional hub axle, or whatever equivalent
    > parts fit against the inside surfaces of the fork ends of a frame. They must match the spacing
    > (see chart) of the frame that the wheels are to be installed in. "
    >
    > It's the locknuts on mine that press against the inside edges whenever the quick-release is
    > tightened.

    There again, on a steal frame a few mm between friends is unlikely to be a problem.

    T
     
  8. Clive George

    Clive George Guest

    "Tony W" <[email protected]> wrote in message news:[email protected]...

    > I think its outside edges -- but wait for confirmation from an expert.

    OLN = over lock nuts

    And its easy to work out it's not the outside - imagine if your dropouts were suddenly made twice
    as thick by putting material on the outside, thus increasing the outside edge distance. Obviously
    the wheel would still fit in exactly the same way (you may need a slightly longer skewer (or axle
    if bolted)).

    cheers, clive
     
  9. Chesney Christ <[email protected]> wrote in message
    news:<[email protected]>...
    >
    > Apparently 126mm is the common size for a 7 speed road bike, going by ol' Sheldon's site. I guess
    > my bike comes from the time when 7 speeds were already fading into obscurity :)

    Some 7sp. threaded road hubs are 130mm, such as the Hope ones; these are convertible by altering the
    positions of certain axle spacers. Oh, and remember to get the wheel re-dished if changing between
    8sp. and 7sp. formats; I found that one out the hard way :-(

    David E. Belcher

    Dept. of Chemistry, University of York
     
  10. A certain David E. Belcher, of uk.rec.cycling "fame", writes :

    >Some 7sp. threaded road hubs are 130mm, such as the Hope ones; these are convertible by altering
    >the positions of certain axle spacers. Oh, and remember to get the wheel re-dished if changing
    >between 8sp. and 7sp. formats; I found that one out the hard way :-(

    Can you expand on that - why is this necessary ?

    --
    George H.W. Bush, as Presidential Nominee for the Republican party; 1987-AUG-27: "No, I don't know
    that Atheists should be considered as citizens, nor should they be considered as patriots. This is
    one nation under God."
     
  11. Chris French

    Chris French Guest

    In message <[email protected]>, Chesney Christ <[email protected]> writes
    >A certain David E. Belcher, of uk.rec.cycling "fame", writes :
    >
    >>Some 7sp. threaded road hubs are 130mm, such as the Hope ones; these are convertible by altering
    >>the positions of certain axle spacers. Oh, and remember to get the wheel re-dished if changing
    >>between 8sp. and 7sp. formats; I found that one out the hard way :-(
    >
    >Can you expand on that - why is this necessary ?
    >
    Presumably , when modifying the hub for 8 speed, you need to swop some spacers over from the
    non-drive side to the drive side to give enough space for the slightly wider 8 speed cassette.

    This effectively moves the flanges of the hub where the spokes attached towards the non -drive side
    and if you didn't redish the wheel, then the rim would end up out of centre.
    --
    Chris French, Leeds
     
  12. A certain chris French, of uk.rec.cycling "fame", writes :

    >Presumably , when modifying the hub for 8 speed, you need to swop some spacers over from the
    >non-drive side to the drive side to give enough space for the slightly wider 8 speed cassette.
    >
    >This effectively moves the flanges of the hub where the spokes attached towards the non -drive side
    >and if you didn't redish the wheel, then the rim would end up out of centre.

    I get it. This is obviously only a concern when someone is retrofitting an existing 7 speed hub with
    an 8/9 speed freehub body. Phew!

    --
    George H.W. Bush, as Presidential Nominee for the Republican party; 1987-AUG-27: "No, I don't know
    that Atheists should be considered as citizens, nor should they be considered as patriots. This is
    one nation under God."
     
  13. chris French <[email protected]> wrote in message
    news:<[email protected]>...
    >
    > This effectively moves the flanges of the hub where the spokes attached towards the non -drive
    > side and if you didn't redish the wheel, then the rim would end up out of centre.

    Absolutely - as such, the rear wheel won't quite follow the same line as the front one; I was
    unaware of this at first as the wrongly dished (my own blunder) 7-to-8 speed conversion was fitted
    to a bike with horizontal dropouts. Probably explained the tendency to wobble at speed, though,
    culminating in escaping serious injury on a descent of Garrowby Hill. The problem only really came
    to light when swapping the same wheel over to my 'cross bike, which has vertical dropouts. Lo and
    behold, it didn't fit properly....

    David E. Belcher

    Dept. of Chemistry, University of York
     
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