• DeRosa Merak Rear Brake

    From Tom Kunich@21:1/5 to All on Thu Jan 2 23:12:55 2025
    I discovered why I got the DeRosa for nearly nothing. When it became time
    to install the rear brake, there is an internally threaded aluminum bolt
    in the hole. The outside of the (front facing) bolt has an allen head on
    it but being aluminum, is stripped. The inside of the device is 5 mm and threadding a screw in until it hits the end does not allow it to be
    unscrewed and I don't want to force it since it is aluminum.

    I have never seen a rear brake that attaches from the rear and an Ultegra
    brake shaft is 5.75 mm. (thread depth on what's present) Now I could drill
    a shaft size hole fron the back but this would leave about 28 mm on the
    other side that needs a hole 8 mm in diameter with stop 10 mm in diameter.
    I could also drill a hole 8 mm in diamerer and the normal connector would
    hold it in the center if the present stop would allow me to tighten it
    enough. Or I could use a steel washer 8 mm ID to spread the load of the
    stop enough to allow me to tighten it enough to lock everything.

    As I say, I've never seen anything like this before and it appears like
    the this thing was either threaded in (unlikely into a carbon fiber rear B- stay) or glued in (extremely poor judgement if so). It also could be
    simply an slight interference fit into the original hole and that would
    explain the reason the allen headed front facing fixture stripped. If this
    were the case, I could thread this deep 5 mm bolt in to the rear id taping
    with a hammer or pushing with a puller, pushing that thing out without any damage to the original hole.

    Now, has anyone else ever seen anything like this and do you have any
    comments? Would you have any suggestions on what to do?

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  • From AMuzi@21:1/5 to Tom Kunich on Thu Jan 2 17:45:52 2025
    On 1/2/2025 5:12 PM, Tom Kunich wrote:
    I discovered why I got the DeRosa for nearly nothing. When it became time
    to install the rear brake, there is an internally threaded aluminum bolt
    in the hole. The outside of the (front facing) bolt has an allen head on
    it but being aluminum, is stripped. The inside of the device is 5 mm and threadding a screw in until it hits the end does not allow it to be
    unscrewed and I don't want to force it since it is aluminum.

    I have never seen a rear brake that attaches from the rear and an Ultegra brake shaft is 5.75 mm. (thread depth on what's present) Now I could drill
    a shaft size hole fron the back but this would leave about 28 mm on the
    other side that needs a hole 8 mm in diameter with stop 10 mm in diameter.
    I could also drill a hole 8 mm in diamerer and the normal connector would hold it in the center if the present stop would allow me to tighten it enough. Or I could use a steel washer 8 mm ID to spread the load of the
    stop enough to allow me to tighten it enough to lock everything.

    As I say, I've never seen anything like this before and it appears like
    the this thing was either threaded in (unlikely into a carbon fiber rear B- stay) or glued in (extremely poor judgement if so). It also could be
    simply an slight interference fit into the original hole and that would explain the reason the allen headed front facing fixture stripped. If this were the case, I could thread this deep 5 mm bolt in to the rear id taping with a hammer or pushing with a puller, pushing that thing out without any damage to the original hole.

    Now, has anyone else ever seen anything like this and do you have any comments? Would you have any suggestions on what to do?


    Your description sounds like a regular M6 brake mounting
    sleeve installed backwards.

    (guys do install calipers behind the seat stays. No
    functional reason to do that. But no technical reason not to
    either. Looks dorky to me. There are setups where the
    slightly different brake reach matters, but that would be
    very rare.)

    Unless there's something I don't know about this, I'd screw
    an M6 bolt into it, warm it with a heat gun (Not hot, warm.
    Carbon adhesives don't like hot) and give it a sharp rap.

    I agree that any drilling, reaming, assault with the dreaded
    Dremel destruction device, or any material removal at all is
    a bad idea until or unless you understand the problem better.
    --
    Andrew Muzi
    am@yellowjersey.org
    Open every day since 1 April, 1971

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From AMuzi@21:1/5 to Tom Kunich on Thu Jan 2 17:46:32 2025
    On 1/2/2025 5:12 PM, Tom Kunich wrote:
    I discovered why I got the DeRosa for nearly nothing. When it became time
    to install the rear brake, there is an internally threaded aluminum bolt
    in the hole. The outside of the (front facing) bolt has an allen head on
    it but being aluminum, is stripped. The inside of the device is 5 mm and threadding a screw in until it hits the end does not allow it to be
    unscrewed and I don't want to force it since it is aluminum.

    I have never seen a rear brake that attaches from the rear and an Ultegra brake shaft is 5.75 mm. (thread depth on what's present) Now I could drill
    a shaft size hole fron the back but this would leave about 28 mm on the
    other side that needs a hole 8 mm in diameter with stop 10 mm in diameter.
    I could also drill a hole 8 mm in diamerer and the normal connector would hold it in the center if the present stop would allow me to tighten it enough. Or I could use a steel washer 8 mm ID to spread the load of the
    stop enough to allow me to tighten it enough to lock everything.

    As I say, I've never seen anything like this before and it appears like
    the this thing was either threaded in (unlikely into a carbon fiber rear B- stay) or glued in (extremely poor judgement if so). It also could be
    simply an slight interference fit into the original hole and that would explain the reason the allen headed front facing fixture stripped. If this were the case, I could thread this deep 5 mm bolt in to the rear id taping with a hammer or pushing with a puller, pushing that thing out without any damage to the original hole.

    Now, has anyone else ever seen anything like this and do you have any comments? Would you have any suggestions on what to do?


    Your description sounds like a regular M6 brake mounting
    sleeve installed backwards.

    (guys do install calipers behind the seat stays. No
    functional reason to do that. But no technical reason not to
    either. Looks dorky to me. There are setups where the
    slightly different brake reach matters, but that would be
    very rare.)

    Unless there's something I don't know about this, I'd screw
    an M6 bolt into it, warm it with a heat gun (Not hot, warm.
    Carbon adhesives don't like hot) and give it a sharp rap.

    I agree that any drilling, reaming, assault with the dreaded
    Dremel destruction device, or any material removal at all is
    a bad idea until or unless you understand the problem better.
    --
    Andrew Muzi
    am@yellowjersey.org
    Open every day since 1 April, 1971

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Zen Cycle@21:1/5 to AMuzi on Fri Jan 3 10:49:48 2025
    On 1/2/2025 6:45 PM, AMuzi wrote:
    On 1/2/2025 5:12 PM, Tom Kunich wrote:
    I discovered why I got the DeRosa for nearly nothing. When it became time
    to install the rear brake, there is an internally threaded aluminum bolt
    in the hole. The outside of the (front facing) bolt has an allen head on
    it but being aluminum, is stripped. The inside of the device is 5 mm and
    threadding a screw in until it hits the end does not allow it to be
    unscrewed and I don't want to force it since it is aluminum.

    I have never seen a rear brake that attaches from the rear and an Ultegra
    brake shaft is 5.75 mm. (thread depth on what's present) Now I could
    drill
    a shaft size hole fron the back but this would leave about 28 mm on the
    other side that needs a hole 8 mm in diameter with stop 10 mm in
    diameter.
    I could also drill a hole 8 mm in diamerer and the normal connector would
    hold it in the center if the present stop would allow me to tighten it
    enough. Or I could use a steel washer 8 mm ID to spread the load of the
    stop enough to allow me to tighten it enough to lock everything.

    As I say, I've never seen anything like this before and it appears like
    the this thing was either threaded in (unlikely into a carbon fiber
    rear B-
    stay) or glued in (extremely poor judgement if so). It also could be
    simply an slight interference fit into the original hole and that would
    explain the reason the allen headed front facing fixture stripped. If
    this
    were the case, I could thread this deep 5 mm bolt in to the rear id
    taping
    with a hammer or pushing with a puller, pushing that thing out without
    any
    damage to the original hole.

    Now, has anyone else ever seen anything like this and do you have any
    comments? Would you have any suggestions on what to do?


    Your description sounds like a regular M6 brake mounting sleeve
    installed backwards.

    (guys do install calipers behind the seat stays. No functional reason to
    do that. But no technical reason not to either. Looks dorky to me. There
    are setups where the slightly different brake reach matters, but that
    would be very rare.)

    Unless there's something I don't know about this, I'd screw an M6 bolt
    into it, warm it with a heat gun (Not hot, warm. Carbon adhesives don't
    like hot) and give it a sharp rap.

    I agree that any drilling, reaming, assault with the dreaded Dremel destruction device, or any material removal at all is a bad idea until
    or unless you understand the problem better.

    "until or unless you understand the problem better."

    That's a pretty tall request considering the intended recipient.


    --
    Add xx to reply

    --- SoupGate-Win32 v1.05
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  • From =?UTF-8?B?Y3ljbGludG9t?=@21:1/5 to All on Fri Jan 3 16:02:52 2025
    On Fri Jan 3 10:49:48 2025 Zen Cycle wrote:
    On 1/2/2025 6:45 PM, AMuzi wrote:
    On 1/2/2025 5:12 PM, Tom Kunich wrote:
    I discovered why I got the DeRosa for nearly nothing. When it became time >> to install the rear brake, there is an internally threaded aluminum bolt >> in the hole. The outside of the (front facing) bolt has an allen head on >> it but being aluminum, is stripped. The inside of the device is 5 mm and >> threadding a screw in until it hits the end does not allow it to be
    unscrewed and I don't want to force it since it is aluminum.

    I have never seen a rear brake that attaches from the rear and an Ultegra >> brake shaft is 5.75 mm. (thread depth on what's present) Now I could
    drill
    a shaft size hole fron the back but this would leave about 28 mm on the
    other side that needs a hole 8 mm in diameter with stop 10 mm in
    diameter.
    I could also drill a hole 8 mm in diamerer and the normal connector would >> hold it in the center if the present stop would allow me to tighten it
    enough. Or I could use a steel washer 8 mm ID to spread the load of the
    stop enough to allow me to tighten it enough to lock everything.

    As I say, I've never seen anything like this before and it appears like
    the this thing was either threaded in (unlikely into a carbon fiber
    rear B-
    stay) or glued in (extremely poor judgement if so). It also could be
    simply an slight interference fit into the original hole and that would
    explain the reason the allen headed front facing fixture stripped. If
    this
    were the case, I could thread this deep 5 mm bolt in to the rear id
    taping
    with a hammer or pushing with a puller, pushing that thing out without
    any
    damage to the original hole.

    Now, has anyone else ever seen anything like this and do you have any
    comments? Would you have any suggestions on what to do?


    Your description sounds like a regular M6 brake mounting sleeve
    installed backwards.

    (guys do install calipers behind the seat stays. No functional reason to
    do that. But no technical reason not to either. Looks dorky to me. There are setups where the slightly different brake reach matters, but that
    would be very rare.)

    Unless there's something I don't know about this, I'd screw an M6 bolt
    into it, warm it with a heat gun (Not hot, warm. Carbon adhesives don't like hot) and give it a sharp rap.

    I agree that any drilling, reaming, assault with the dreaded Dremel destruction device, or any material removal at all is a bad idea until
    or unless you understand the problem better.

    "until or unless you understand the problem better."

    That's a pretty tall request considering the intended recipient.




    The coward speaks again from the position of anonymity.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From AMuzi@21:1/5 to Zen Cycle on Fri Jan 3 10:19:22 2025
    On 1/3/2025 9:49 AM, Zen Cycle wrote:
    On 1/2/2025 6:45 PM, AMuzi wrote:
    On 1/2/2025 5:12 PM, Tom Kunich wrote:
    I discovered why I got the DeRosa for nearly nothing.
    When it became time
    to install the rear brake, there is an internally
    threaded aluminum bolt
    in the hole. The outside of the (front facing) bolt has
    an allen head on
    it but being aluminum, is stripped. The inside of the
    device is 5 mm and
    threadding a screw in until it hits the end does not
    allow it to be
    unscrewed and I don't want to force it since it is aluminum.

    I have never seen a rear brake that attaches from the
    rear and an Ultegra
    brake shaft is 5.75 mm. (thread depth on what's present)
    Now I could drill
    a shaft size hole fron the back but this would leave
    about 28 mm on the
    other side that needs a hole 8 mm in diameter with stop
    10 mm in diameter.
    I could also drill a hole 8 mm in diamerer and the normal
    connector would
    hold it in the center if the present stop would allow me
    to tighten it
    enough. Or I could use a steel washer 8 mm ID to spread
    the load of the
    stop enough to allow me to tighten it enough to lock
    everything.

    As I say, I've never seen anything like this before and
    it appears like
    the this thing was either threaded in (unlikely into a
    carbon fiber rear B-
    stay) or glued in (extremely poor judgement if so). It
    also could be
    simply an slight interference fit into the original hole
    and that would
    explain the reason the allen headed front facing fixture
    stripped. If this
    were the case, I could thread this deep 5 mm bolt in to
    the rear id taping
    with a hammer or pushing with a puller, pushing that
    thing out without any
    damage to the original hole.

    Now, has anyone else ever seen anything like this and do
    you have any
    comments? Would you have any suggestions on what to do?


    Your description sounds like a regular M6 brake mounting
    sleeve installed backwards.

    (guys do install calipers behind the seat stays. No
    functional reason to do that. But no technical reason not
    to either. Looks dorky to me. There are setups where the
    slightly different brake reach matters, but that would be
    very rare.)

    Unless there's something I don't know about this, I'd
    screw an M6 bolt into it, warm it with a heat gun (Not
    hot, warm. Carbon adhesives don't like hot) and give it a
    sharp rap.

    I agree that any drilling, reaming, assault with the
    dreaded Dremel destruction device, or any material removal
    at all is a bad idea until or unless you understand the
    problem better.

    "until or unless you understand the problem better."

    That's a pretty tall request considering the intended
    recipient.



    Well, yes.
    Hard to offer definitive advice when the problem is poorly
    described.

    --
    Andrew Muzi
    am@yellowjersey.org
    Open every day since 1 April, 1971

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From =?UTF-8?B?Y3ljbGludG9t?=@21:1/5 to All on Fri Jan 3 20:46:00 2025
    On Fri Jan 3 11:52:19 2025 Frank Krygowski wrote:
    On 1/3/2025 11:19 AM, AMuzi wrote:
    On 1/3/2025 9:49 AM, Zen Cycle wrote:
    On 1/2/2025 6:45 PM, AMuzi wrote:
    On 1/2/2025 5:12 PM, Tom Kunich wrote:
    I discovered why I got the DeRosa for nearly nothing. When it became >>>> time
    to install the rear brake, there is an internally threaded aluminum
    bolt
    in the hole. The outside of the (front facing) bolt has an allen
    head on
    it but being aluminum, is stripped. The inside of the device is 5 mm >>>> and
    threadding a screw in until it hits the end does not allow it to be
    unscrewed and I don't want to force it since it is aluminum.

    I have never seen a rear brake that attaches from the rear and an
    Ultegra
    brake shaft is 5.75 mm. (thread depth on what's present) Now I could >>>> drill
    a shaft size hole fron the back but this would leave about 28 mm on the >>>> other side that needs a hole 8 mm in diameter with stop 10 mm in
    diameter.
    I could also drill a hole 8 mm in diamerer and the normal connector
    would
    hold it in the center if the present stop would allow me to tighten it >>>> enough. Or I could use a steel washer 8 mm ID to spread the load of the >>>> stop enough to allow me to tighten it enough to lock everything.

    As I say, I've never seen anything like this before and it appears like >>>> the this thing was either threaded in (unlikely into a carbon fiber
    rear B-
    stay) or glued in (extremely poor judgement if so). It also could be >>>> simply an slight interference fit into the original hole and that would >>>> explain the reason the allen headed front facing fixture stripped.
    If this
    were the case, I could thread this deep 5 mm bolt in to the rear id
    taping
    with a hammer or pushing with a puller, pushing that thing out
    without any
    damage to the original hole.

    Now, has anyone else ever seen anything like this and do you have any >>>> comments? Would you have any suggestions on what to do?


    Your description sounds like a regular M6 brake mounting sleeve
    installed backwards.

    (guys do install calipers behind the seat stays. No functional reason
    to do that. But no technical reason not to either. Looks dorky to me.
    There are setups where the slightly different brake reach matters,
    but that would be very rare.)

    Unless there's something I don't know about this, I'd screw an M6
    bolt into it, warm it with a heat gun (Not hot, warm. Carbon
    adhesives don't like hot) and give it a sharp rap.

    I agree that any drilling, reaming, assault with the dreaded Dremel
    destruction device, or any material removal at all is a bad idea
    until or unless you understand the problem better.

    "until or unless you understand the problem better."

    That's a pretty tall request considering the intended recipient.



    Well, yes.
    Hard to offer definitive advice when the problem is poorly described.

    I too found the description to be poor. Again, I think if Tom gave some
    close up photos from different angles, plus (say) a decent engineering drawing or sketch of the troublesome insert, he'd have a better chance
    of getting some good advice.




    After all, no one and especially you knows what a B-Stay is and although there are at least three different names for what is presently called a pivot screw, it is impossible to understand "brake locking screw".

    You need an engineering drawing, but then you needed and engineering drawing of a splined hollow crankset. without an engineering drawing (when you could look on Ebay and see the actual thing.) You think that the crankset should "wobble" before it falls
    off.

    I managed without a degree in mechanical engineering or a PE to figure out a way to repair it but sinxe no on can understand my terminology there is no use in explaining it.

    --- SoupGate-Win32 v1.05
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