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new Fury RoadMaster test

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Published
15 August 2004
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3 October 2004
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  1. Yikes! Disaster struck the Fury RoadMaster! Those interested
    in technical questions should skip to the end for a picture
    and a question.

    Wheeling it away from where it sleeps with one pedal up on a
    wooden picnic bench, I heard an odd sound.

    Rolling it back and forth revealed that the sound came from
    the rear wheel at one particular point.

    Brakes? No, the pads weren't touching the rim.

    Tire rubbing against the frame? No, there was room for a big
    rat to crawl through between the tire and the chain stays or
    seat stays when the noise was heard.

    Something caught in the plastic spoke protector? No, it spun
    freely.

    A mechanical disaster inside the freewheel or--

    Oh. I see. The massively treaded rear tire is almost flat.

    The noise comes when a section of the bead that's almost
    loose rolls under the hub and gets squeezed back against the
    rim.

    The Fury is flipped onto its back with its thumb-shifters
    and speedometer held off the back porch concrete by a wooden
    2x4 frame (nothing is too good for a high-quality bicycle).
    An adjustable wrench loosens the axle nuts, and out comes
    the rear wheel.

    Hmmm . . . a bit heavier than my touring bike's wheel.

    A thumbnail depresses the Schrader valve enough to let the
    rest of the air out and the monster tire comes off the rim
    quite easily.

    Odd, nothing stuck in the tire, rim strip in place, no
    apparent hole in the tire. It's almost sunset, so to hell
    with it for now.

    One of three spare 2x26 tubes bought on sale goes in and the
    tire goes back on the rim almost as easily as it came off.
    After a brief introduction to Mr. Air Compressor, the tire
    seats nicely and--

    D'oh! When inflated, gargantuan treaded tires do not slip
    past the brake pads. Thumbnail adjustment of the air
    pressure eventually reduces the stiff and swollen tire
    enough for its return to its rightful place, followed by
    another CPR session with the air compressor.

    After an uneventful ride, the suspect tube is placed in the
    dunking stool of the kitchen sink and quickly found guilty.
    A tiny stream of bubbles leaks out from underneath an odd
    gash--a flap, really--on the edge of the circle where the
    valve stem attaches to the tube.

    The tire went flat overnight after over 160 four-mile rides,
    so whatever created the tiny flap happened yesterday, but
    the rim strip was in place.

    Closer examination shows that the rubber seems to have
    split, bursting from the inside and peeling up a tiny flap
    roughly over one spoke hole next to the valve.

    Viewed in profile, little bulges appear on either side of
    the inner tube's valve stem. Further away, around the inside
    of the tube, are a few more odd bulges.

    They seem to be centered over the spoke heads, with a dent
    in the tube where it sat on the spoke head and a bulge on
    either side. Here's a picture of the clearest example:

    http://home.comcast.net/~carlfogel/download/tubebump.jpg

    The spoke head was under the "in" of "Shin" and the shiny
    bumps on either side are protruding. Most of these marks
    amount to little more than scuff marks.

    Why are there raised bumps on either side of the inner tube
    where it sits on the spoke head? Why does the rubber distort
    like this?

    Carl Fogel

  2. Quoted message said:

    They seem to be centered over the spoke heads, with a dent
    in the tube where it sat on the spoke head and a bulge on
    either side. Here's a picture of the clearest example:

    http://home.comcast.net/~carlfogel/download/tubebump.jpg

    The spoke head was under the "in" of "Shin" and the shiny
    bumps on either side are protruding. Most of these marks
    amount to little more than scuff marks.

    Why are there raised bumps on either side of the inner tube
    where it sits on the spoke head? Why does the rubber distort
    like this?

    If it was a box section rim, I'd suggest a deformation of the rubber
    where it stretched down into the spoke hole.

    Nasty, cheap rubber rim strips, right? On another bike, it'd be worth
    replacing them with cloth or nylon rim strips. For this bike, the old
    strapping tape trick is probably more appropriate.

    --
    Warren Block * Rapid City, South Dakota * USA

  3. Quoted message said:

    Closer examination shows that the rubber seems to have
    split, bursting from the inside and peeling up a tiny flap
    roughly over one spoke hole next to the valve.

    It might be interesting to see a pic of the rim in that area. I may
    just peel the tire on a Roadmaster out back to see what's likely to be
    going on.

    Quoted message said:

    Viewed in profile, little bulges appear on either side of
    the inner tube's valve stem. Further away, around the inside
    of the tube, are a few more odd bulges.

    They seem to be centered over the spoke heads, with a dent
    in the tube where it sat on the spoke head and a bulge on
    either side. Here's a picture of the clearest example:

    http://home.comcast.net/~carlfogel/download/tubebump.jpg

    Yup, that looks like the classic long-term-squirm that I've been
    seeing for many years on tubes taken from wheels whose rims have
    non-recessed spoke heads. Does your Fury have those really thin rim
    bands?

    Quoted message said:

    The spoke head was under the "in" of "Shin" and the shiny
    bumps on either side are protruding. Most of these marks
    amount to little more than scuff marks.

    The fact that this is a low-bidder tube may have some bearing on the
    results.

    Quoted message said:

    Why are there raised bumps on either side of the inner tube
    where it sits on the spoke head? Why does the rubber distort
    like this?

    I called it "long-term-squirm" above because that's the best
    description I could come up with. The spoke head's "bump" in the rim
    band causes a stretching on each side which doesn't fully settle in
    right away; instead, when the tube is first inflated, the band
    partially bridges from the nipple's shoulder o the rim interior, but
    as the tire sits inflated, the band deforms to hug the shoulder, and
    the tube deforms with it...outward, into the crevice, producing a bump
    on the tube.

    Check the tension of the spoke at that position. It may be a trifle
    loose.

    FYI, yet another Roadmaster (a Mt Climber this time) fell into the
    pile a couple of weeks back; my daughter says it's got good gearing
    but horrible brakes and an atrocious seat. Since the Roadmasters are
    pretty much the only mountain bikes that the thieves didn't take when
    I was hit a little over a week ago, I have decided that all of my
    mountain bikes will be getting Roadmaster decals...when I have some
    mountain bikes worth riding again, anyway.
    --
    Typoes are a feature, not a bug.
    Some gardening required to reply via email.
    Words processed in a facility that contains nuts.

  4. Warren Block said:

    Nasty, cheap rubber rim strips, right? On another bike, it'd be worth
    replacing them with cloth or nylon rim strips. For this bike, the old
    strapping tape trick is probably more appropriate.

    i suggest putting it out of our misery. use slugs. post pictures.
    --
    david reuteler
    [email hidden]

  5. [email hidden] wrote in message ...

    Quoted message said:


    Why are there raised bumps on either side of the inner tube
    where it sits on the spoke head? Why does the rubber distort
    like this?

    Because that's the way of the world.

    Trevor

  6. Warren Block said:
    Quoted message said:

    They seem to be centered over the spoke heads, with a dent
    in the tube where it sat on the spoke head and a bulge on
    either side. Here's a picture of the clearest example:

    http://home.comcast.net/~carlfogel/download/tubebump.jpg

    The spoke head was under the "in" of "Shin" and the shiny
    bumps on either side are protruding. Most of these marks
    amount to little more than scuff marks.

    Why are there raised bumps on either side of the inner tube
    where it sits on the spoke head? Why does the rubber distort
    like this?

    If it was a box section rim, I'd suggest a deformation of the rubber
    where it stretched down into the spoke hole.

    Nasty, cheap rubber rim strips, right? On another bike, it'd be worth
    replacing them with cloth or nylon rim strips. For this bike, the old
    strapping tape trick is probably more appropriate.

    Dear Warren,

    I'm afraid that I don't follow you, or perhaps you've
    misunderstood me--sorry if I didn't make things clear.

    The Fury RoadMaster's spokes stand proudly above the
    inside of the rim, fearlessly facing the inner tube's
    pressure instead of cowering in holes like certain modern
    rim designs that I scorn to mention, cowards that huddle
    under the surface of the rim and hope that the roof holds.

    A handsome gray rubber rim strip (all the ones that I'd seen
    before this were black) protects the inner tube from the
    rugged contours of the Fury's spokes. This strip is in place
    and undamaged.

    As far as I can tell, neither nylon nor cloth nor strapping
    tape would offer more protection than what are customarily
    suits of solemn black. The well-tensioned spoke heads bulge
    up through any reasonably thin material and are somehow
    deforming the bejesus out of the inner curve of the inner
    tube, here and there.

    Carl Fogel

  7. Quoted message said:

    The Fury RoadMaster's spokes stand proudly above the
    inside of the rim, fearlessly facing the inner tube's
    pressure instead of cowering in holes like certain modern
    rim designs that I scorn to mention, cowards that huddle
    under the surface of the rim and hope that the roof holds.

    Crappy non-box-section rim, check.

    Quoted message said:

    A handsome gray rubber rim strip (all the ones that I'd seen
    before this were black) protects the inner tube from the
    rugged contours of the Fury's spokes. This strip is in place
    and undamaged.

    Ultra-cheap rubber rim strip, got it.

    Quoted message said:

    As far as I can tell, neither nylon nor cloth nor strapping
    tape would offer more protection than what are customarily
    suits of solemn black. The well-tensioned spoke heads bulge
    up through any reasonably thin material and are somehow
    deforming the bejesus out of the inner curve of the inner
    tube, here and there.

    Years back I found that sharp edges in a rim could cut through rubber
    rim strips. Don't recall any visible holes in the rim strip; maybe a
    sharp edge can cause a pinch flat in the tube without leaving a cut in
    the rim strip. Strapping tape should have enough strength to keep the
    tube from getting pinched by the nipple screwdriver slot, and, unlike
    Velox rim strips, won't be worth more than the wheel it's on.

    Sorry, let me rephrase that to match the thread:

    Strapping tape may hold a lowly position in the stratified realms of
    cycledom, yet its noble--and humbly silent--strength can resist the
    relentless pneumatic butyl imposition where the dignified gray rim strip
    would politely bow to pressure. Traditional rim strips would be gaudy
    and financially inappropriate for the transportational marvel you've
    described, but humble strapping tape will not embarrass.

    --
    Warren Block * Rapid City, South Dakota * USA

  8. Warren Block said:
    Quoted message said:

    The Fury RoadMaster's spokes stand proudly above the
    inside of the rim, fearlessly facing the inner tube's
    pressure instead of cowering in holes like certain modern
    rim designs that I scorn to mention, cowards that huddle
    under the surface of the rim and hope that the roof holds.

    Crappy non-box-section rim, check.

    Quoted message said:

    A handsome gray rubber rim strip (all the ones that I'd seen
    before this were black) protects the inner tube from the
    rugged contours of the Fury's spokes. This strip is in place
    and undamaged.

    Ultra-cheap rubber rim strip, got it.

    Quoted message said:

    As far as I can tell, neither nylon nor cloth nor strapping
    tape would offer more protection than what are customarily
    suits of solemn black. The well-tensioned spoke heads bulge
    up through any reasonably thin material and are somehow
    deforming the bejesus out of the inner curve of the inner
    tube, here and there.

    Years back I found that sharp edges in a rim could cut through rubber
    rim strips. Don't recall any visible holes in the rim strip; maybe a
    sharp edge can cause a pinch flat in the tube without leaving a cut in
    the rim strip. Strapping tape should have enough strength to keep the
    tube from getting pinched by the nipple screwdriver slot, and, unlike
    Velox rim strips, won't be worth more than the wheel it's on.

    Sorry, let me rephrase that to match the thread:

    Strapping tape may hold a lowly position in the stratified realms of
    cycledom, yet its noble--and humbly silent--strength can resist the
    relentless pneumatic butyl imposition where the dignified gray rim strip
    would politely bow to pressure. Traditional rim strips would be gaudy
    and financially inappropriate for the transportational marvel you've
    described, but humble strapping tape will not embarrass.

    Dear Warren,

    While I admire your enthusiasm for mightier methods of
    covering spokes, I have to clarify things to make sure that
    the lowly rubber strips are not the victims of a
    misunderstanding.

    The tube didn't pinch or puncture over the spoke head.

    The odd bulge to one side of the spoke head dent burst
    outward, possibly because this particular bulge was in the
    stiffer round reinforced section around the valve stem.

    It isn't even a true burst in the sense of a star. There's a
    roughly triangular flap and presumably a tiny leak lurking
    under the base of the flap.

    Here's a profile view:

    http://home.comcast.net/~carlfogel/download/tubebump2.jpg

    To the right of the valve stem you can see the tongue of the
    tiny flap sticking up on the near side of the odd bulge. To
    the right of the flap is the peak of the odd bulge. The
    spoke-head mark is to the right of that peak.

    In other words, the spoke-head was on the far side of the
    bulge from the flap. Something about the inner tube didn't
    like being forced into that odd bulge and burst along the
    edge where the circle of reinforced rubber around the valve
    stem stops.

    Carl Fogel

  9. On Mon, 16 Aug 2004 03:33:38 -0000, Warren Block <[email hidden]>

    Quoted message said:

    Sorry, let me rephrase that to match the thread:

    Strapping tape may hold a lowly position in the stratified realms of
    cycledom, yet its noble--and humbly silent--strength can resist the
    relentless pneumatic butyl imposition where the dignified gray rim strip
    would politely bow to pressure. Traditional rim strips would be gaudy
    and financially inappropriate for the transportational marvel you've
    described, but humble strapping tape will not embarrass.

    You *did* use purple electrons to compose that, right? ;>

    In years gone by, I found that tube failures on such rims could be
    reduced by using two rim bands; one punched to go around all of the
    spoke heads, and the other covering them. The holey band went on
    first, then the unholey one. I haven't ridden many miles on a bike
    with rims that needed such subterfuges since my days of pitching
    newspapers from an EA-3-equipped 3-speed, but I used the trick to good
    advantage back then. (I also seldom rode a tube that didn't have at
    least three or four patches on it.)
    --
    Typoes are a feature, not a bug.
    Some gardening required to reply via email.
    Words processed in a facility that contains nuts.

  10. What you need is a heavily braided tape that comes with a little buckle on
    the end, available from a bike shop near me, and most probably elsewhere.
    The proprietor swears by them, usually when he's banged his head on the BMX
    chainring hanging above the home of said rim tape. Have no definitive
    description other than rim tape afaik. He also reckons on using moped
    chains as the economic and safe choice for single speeds. He has otherwise
    had returned machines due to 'snapped chains' and so routinely changes
    chains on new bmx machines.

    Trevor

  11. Quoted message said:
    Warren Block said:
    Quoted message said:

    The Fury RoadMaster's spokes stand proudly above the
    inside of the rim, fearlessly facing the inner tube's
    pressure instead of cowering in holes like certain modern
    rim designs that I scorn to mention, cowards that huddle
    under the surface of the rim and hope that the roof holds.

    Crappy non-box-section rim, check.

    Quoted message said:

    A handsome gray rubber rim strip (all the ones that I'd seen
    before this were black) protects the inner tube from the
    rugged contours of the Fury's spokes. This strip is in place
    and undamaged.

    Ultra-cheap rubber rim strip, got it.

    Quoted message said:

    As far as I can tell, neither nylon nor cloth nor strapping
    tape would offer more protection than what are customarily
    suits of solemn black. The well-tensioned spoke heads bulge
    up through any reasonably thin material and are somehow
    deforming the bejesus out of the inner curve of the inner
    tube, here and there.

    Years back I found that sharp edges in a rim could cut through rubber
    rim strips. Don't recall any visible holes in the rim strip; maybe a
    sharp edge can cause a pinch flat in the tube without leaving a cut in
    the rim strip. Strapping tape should have enough strength to keep the
    tube from getting pinched by the nipple screwdriver slot, and, unlike
    Velox rim strips, won't be worth more than the wheel it's on.

    Sorry, let me rephrase that to match the thread:

    Strapping tape may hold a lowly position in the stratified realms of
    cycledom, yet its noble--and humbly silent--strength can resist the
    relentless pneumatic butyl imposition where the dignified gray rim strip
    would politely bow to pressure. Traditional rim strips would be gaudy
    and financially inappropriate for the transportational marvel you've
    described, but humble strapping tape will not embarrass.

    Dear Warren,

    While I admire your enthusiasm for mightier methods of
    covering spokes, I have to clarify things to make sure that
    the lowly rubber strips are not the victims of a
    misunderstanding.

    The tube didn't pinch or puncture over the spoke head.

    The odd bulge to one side of the spoke head dent burst
    outward, possibly because this particular bulge was in the
    stiffer round reinforced section around the valve stem.

    It isn't even a true burst in the sense of a star. There's a
    roughly triangular flap and presumably a tiny leak lurking
    under the base of the flap.

    Here's a profile view:

    http://home.comcast.net/~carlfogel/download/tubebump2.jpg

    To the right of the valve stem you can see the tongue of the
    tiny flap sticking up on the near side of the odd bulge. To
    the right of the flap is the peak of the odd bulge. The
    spoke-head mark is to the right of that peak.

    In other words, the spoke-head was on the far side of the
    bulge from the flap. Something about the inner tube didn't
    like being forced into that odd bulge and burst along the
    edge where the circle of reinforced rubber around the valve
    stem stops.

    Carl Fogel

    carl, just file away the part of the spoke that protrudes above the
    nipple head, then use a thick cloth rim tape - it's really the best you
    can do without moving to a decent box section rim. a better quality
    tube might help too - that rubber has clearly crept. when seeking an
    alternative, bear in mind that most tubes these days come from similar
    factories to the one yours came from, regardless of the fancy name on
    the box.

    i'd also suggest moving to a decent wheelset, but i know the roadmaster
    is a project for you.

  12. jim beam said:
    Quoted message said:
    Warren Block said:

    [email hidden] <[email hidden]> wrote:

    >The Fury RoadMaster's spokes stand proudly above the
    >inside of the rim, fearlessly facing the inner tube's
    >pressure instead of cowering in holes like certain modern
    >rim designs that I scorn to mention, cowards that huddle
    >under the surface of the rim and hope that the roof holds.

    Crappy non-box-section rim, check.

    >A handsome gray rubber rim strip (all the ones that I'd seen
    >before this were black) protects the inner tube from the
    >rugged contours of the Fury's spokes. This strip is in place
    >and undamaged.

    Ultra-cheap rubber rim strip, got it.

    >As far as I can tell, neither nylon nor cloth nor strapping
    >tape would offer more protection than what are customarily
    >suits of solemn black. The well-tensioned spoke heads bulge
    >up through any reasonably thin material and are somehow
    >deforming the bejesus out of the inner curve of the inner
    >tube, here and there.

    Years back I found that sharp edges in a rim could cut through rubber
    rim strips. Don't recall any visible holes in the rim strip; maybe a
    sharp edge can cause a pinch flat in the tube without leaving a cut in
    the rim strip. Strapping tape should have enough strength to keep the
    tube from getting pinched by the nipple screwdriver slot, and, unlike
    Velox rim strips, won't be worth more than the wheel it's on.

    Sorry, let me rephrase that to match the thread:

    Strapping tape may hold a lowly position in the stratified realms of
    cycledom, yet its noble--and humbly silent--strength can resist the
    relentless pneumatic butyl imposition where the dignified gray rim strip
    would politely bow to pressure. Traditional rim strips would be gaudy
    and financially inappropriate for the transportational marvel you've
    described, but humble strapping tape will not embarrass.

    Dear Warren,

    While I admire your enthusiasm for mightier methods of
    covering spokes, I have to clarify things to make sure that
    the lowly rubber strips are not the victims of a
    misunderstanding.

    The tube didn't pinch or puncture over the spoke head.

    The odd bulge to one side of the spoke head dent burst
    outward, possibly because this particular bulge was in the
    stiffer round reinforced section around the valve stem.

    It isn't even a true burst in the sense of a star. There's a
    roughly triangular flap and presumably a tiny leak lurking
    under the base of the flap.

    Here's a profile view:

    http://home.comcast.net/~carlfogel/download/tubebump2.jpg

    To the right of the valve stem you can see the tongue of the
    tiny flap sticking up on the near side of the odd bulge. To
    the right of the flap is the peak of the odd bulge. The
    spoke-head mark is to the right of that peak.

    In other words, the spoke-head was on the far side of the
    bulge from the flap. Something about the inner tube didn't
    like being forced into that odd bulge and burst along the
    edge where the circle of reinforced rubber around the valve
    stem stops.

    Carl Fogel

    carl, just file away the part of the spoke that protrudes above the
    nipple head, then use a thick cloth rim tape - it's really the best you
    can do without moving to a decent box section rim. a better quality
    tube might help too - that rubber has clearly crept. when seeking an
    alternative, bear in mind that most tubes these days come from similar
    factories to the one yours came from, regardless of the fancy name on
    the box.

    i'd also suggest moving to a decent wheelset, but i know the roadmaster
    is a project for you.

    Dear Jim,

    I may still be failing to make things clear, so here's a
    diagram for fixed-font.

    valve

    | | bulge1 bulge2
    | | _ - _ spoke nipple _ - _
    | |___ * - _ dent _ - - _ _ _
    - _ -

    * burst

    I should have said "spoke nipple" dent instead of "spoke
    head" dent--the heads of the spokes do not protrude at all
    from the nipples.

    Carl Fogel

  13. Quoted message said:
    Quoted message said:

    [email hidden] <[email hidden]> wrote:


    Here's a profile view:

    http://home.comcast.net/~carlfogel/download/tubebump2.jpg

    Dear Carl,

    Excellent photograph!

    Judging from the shape of the distended inner tube walls, and the fact
    that the burst appears to "point" towards the valve, and the fact the
    burst is very near to the edge of the rubber around the valve base, I
    suspect neither spokes nor rim tape have anything to do with your
    damaged tube.

    It seems likely that the burst might have been caused by something
    like the following scenario:

    1. The valve might have been pushed into the interior of the tire
    before or during initial inflation (perhaps at the 'Mart, maybe even
    due to the force of the chuck on the valve).

    2. This would have raised the reinforced valve base off the rim floor,

    3. creating a gap between the valve base and the rim.

    4. Then maybe the thinner and more flexible walls of the inner tube
    stretched toward the valve stem in an attempt to fill this gap.

    5. Once stretched, the tube might have slowly begun to distend
    until...

    6. One day it stretched too far, couldn't hold the air any longer and
    burst. (It might take some time to develop permanently distended inner
    tube walls).

    Does that seem to make sense? Of course, I could be completely
    wrong...

  14. Quoted message said:

    Yikes! Disaster struck the Fury RoadMaster! Those interested
    in technical questions should skip to the end for a picture
    and a question.

    Quoted message said:

    http://home.comcast.net/~carlfogel/download/tubebump.jpg

    The spoke head was under the "in" of "Shin" and the shiny
    bumps on either side are protruding. Most of these marks
    amount to little more than scuff marks.

    Why are there raised bumps on either side of the inner tube
    where it sits on the spoke head? Why does the rubber distort
    like this?

    Carl,

    The vast majority of Fury Roadmaster riders grace their tubes
    with the embrace of a pump-chuck at intervals roughly equivalent
    to those of Olympic years (Summer variety). Your regular
    application of a brutish air-compressor to the Fury Roadmaster
    is surely stressing the components well beyond their design limits,
    deforming the tubes to the shape of their crudely constructed
    pressure vessel.

    Ride the bicycle no more. It may explode at any moment.

  15. On 16 Aug 2004 18:34:21 -0700, [email hidden] (Benjamin Weiner)

    Quoted message said:

    Carl,

    The vast majority of Fury Roadmaster riders grace their tubes
    with the embrace of a pump-chuck at intervals roughly equivalent
    to those of Olympic years (Summer variety). Your regular
    application of a brutish air-compressor to the Fury Roadmaster
    is surely stressing the components well beyond their design limits,
    deforming the tubes to the shape of their crudely constructed
    pressure vessel.

    Ride the bicycle no more. It may explode at any moment.

    You, sir, are getting entirely too good at Fogeling.

    Practice makes perfect. Don't stop now.
    --
    Typoes are a feature, not a bug.
    Some gardening required to reply via email.
    Words processed in a facility that contains nuts.

  16. On 16 Aug 2004 18:34:21 -0700, [email hidden]

    (Benjamin Weiner) said:
    Quoted message said:

    Yikes! Disaster struck the Fury RoadMaster! Those interested
    in technical questions should skip to the end for a picture
    and a question.

    Quoted message said:

    http://home.comcast.net/~carlfogel/download/tubebump.jpg

    The spoke head was under the "in" of "Shin" and the shiny
    bumps on either side are protruding. Most of these marks
    amount to little more than scuff marks.

    Why are there raised bumps on either side of the inner tube
    where it sits on the spoke head? Why does the rubber distort
    like this?

    Carl,

    The vast majority of Fury Roadmaster riders grace their tubes
    with the embrace of a pump-chuck at intervals roughly equivalent
    to those of Olympic years (Summer variety). Your regular
    application of a brutish air-compressor to the Fury Roadmaster
    is surely stressing the components well beyond their design limits,
    deforming the tubes to the shape of their crudely constructed
    pressure vessel.

    Ride the bicycle no more. It may explode at any moment.

    Dear Benjamin,

    Your warning falls too late upon deaf ears--166 rides,
    673.96 miles, one flat tire, and dozens of terrified geese
    scuttling off the road in the City Park.

    However, you may have hit upon an explanation for the oddly
    irregular bumps on either side of the nipples, with many
    areas showing little beyond scuff marks.

    It could be that the plump inner tube has trouble expanding
    down into the deep, narrow well of the rim and that in some
    places the mere 55 psi recommended fails to push the tube
    firmly against the bottom of the rim.

    Hmmm . . . maybe I need to try higher pressures?

    Carl Fogel

  17. dianne_1234 said:
    Quoted message said:
    Quoted message said:

    [email hidden] <[email hidden]> wrote:


    Here's a profile view:

    http://home.comcast.net/~carlfogel/download/tubebump2.jpg

    Dear Carl,

    Excellent photograph!

    Judging from the shape of the distended inner tube walls, and the fact
    that the burst appears to "point" towards the valve, and the fact the
    burst is very near to the edge of the rubber around the valve base, I
    suspect neither spokes nor rim tape have anything to do with your
    damaged tube.

    It seems likely that the burst might have been caused by something
    like the following scenario:

    1. The valve might have been pushed into the interior of the tire
    before or during initial inflation (perhaps at the 'Mart, maybe even
    due to the force of the chuck on the valve).

    2. This would have raised the reinforced valve base off the rim floor,

    3. creating a gap between the valve base and the rim.

    4. Then maybe the thinner and more flexible walls of the inner tube
    stretched toward the valve stem in an attempt to fill this gap.

    5. Once stretched, the tube might have slowly begun to distend
    until...

    6. One day it stretched too far, couldn't hold the air any longer and
    burst. (It might take some time to develop permanently distended inner
    tube walls).

    Does that seem to make sense? Of course, I could be completely
    wrong...

    Dear Dianne,

    Your compliment on the photography is appreciated.

    Here at Fogel Labs, only the finest $15 WalMart USB cameras
    are used, clipped onto an 18-inch wooden ruler clamped into
    an otherwise idle machinst's angle vise.

    Your idea that the valve stem may have been holding the
    inside of the inner tube away from the rim strikes me as
    quite sensible--otherwise, the rubber could not have burst
    outward.

    (I'm not at all jealous that you thought of this and that I
    didn't. Not at all.)

    In addition to the valve stem possibly jamming a little and
    holding the tube up, the well for the spokes in the Fury's
    broad rim is deep and narrow, so the inner tube could have
    some trouble squashing down far enough to touch the metal at
    the very bottom, where the tiny burst occurred.

    The stiffer round area around the base of the valve stem
    would have also helped hold things away from the rim, just
    as you suggest.

    Green-eyed,

    Carl Fogel

  18. Quoted message said:
    jim beam said:
    Quoted message said:

    On Mon, 16 Aug 2004 03:33:38 -0000, Warren Block
    <[email hidden]> wrote:

    >[email hidden] <[email hidden]> wrote:
    >
    >
    >
    >>The Fury RoadMaster's spokes stand proudly above the
    >>inside of the rim, fearlessly facing the inner tube's
    >>pressure instead of cowering in holes like certain modern
    >>rim designs that I scorn to mention, cowards that huddle
    >>under the surface of the rim and hope that the roof holds.
    >
    >Crappy non-box-section rim, check.
    >
    >
    >
    >>A handsome gray rubber rim strip (all the ones that I'd seen
    >>before this were black) protects the inner tube from the
    >>rugged contours of the Fury's spokes. This strip is in place
    >>and undamaged.
    >
    >Ultra-cheap rubber rim strip, got it.
    >
    >
    >
    >>As far as I can tell, neither nylon nor cloth nor strapping
    >>tape would offer more protection than what are customarily
    >>suits of solemn black. The well-tensioned spoke heads bulge
    >>up through any reasonably thin material and are somehow
    >>deforming the bejesus out of the inner curve of the inner
    >>tube, here and there.
    >
    >Years back I found that sharp edges in a rim could cut through rubber
    >rim strips. Don't recall any visible holes in the rim strip; maybe a
    >sharp edge can cause a pinch flat in the tube without leaving a cut in
    >the rim strip. Strapping tape should have enough strength to keep the
    >tube from getting pinched by the nipple screwdriver slot, and, unlike
    >Velox rim strips, won't be worth more than the wheel it's on.
    >
    >Sorry, let me rephrase that to match the thread:
    >
    >Strapping tape may hold a lowly position in the stratified realms of
    >cycledom, yet its noble--and humbly silent--strength can resist the
    >relentless pneumatic butyl imposition where the dignified gray rim strip
    >would politely bow to pressure. Traditional rim strips would be gaudy
    >and financially inappropriate for the transportational marvel you've
    >described, but humble strapping tape will not embarrass.

    Dear Warren,

    While I admire your enthusiasm for mightier methods of
    covering spokes, I have to clarify things to make sure that
    the lowly rubber strips are not the victims of a
    misunderstanding.

    The tube didn't pinch or puncture over the spoke head.

    The odd bulge to one side of the spoke head dent burst
    outward, possibly because this particular bulge was in the
    stiffer round reinforced section around the valve stem.

    It isn't even a true burst in the sense of a star. There's a
    roughly triangular flap and presumably a tiny leak lurking
    under the base of the flap.

    Here's a profile view:

    http://home.comcast.net/~carlfogel/download/tubebump2.jpg

    To the right of the valve stem you can see the tongue of the
    tiny flap sticking up on the near side of the odd bulge. To
    the right of the flap is the peak of the odd bulge. The
    spoke-head mark is to the right of that peak.

    In other words, the spoke-head was on the far side of the
    bulge from the flap. Something about the inner tube didn't
    like being forced into that odd bulge and burst along the
    edge where the circle of reinforced rubber around the valve
    stem stops.

    Carl Fogel

    carl, just file away the part of the spoke that protrudes above the
    nipple head, then use a thick cloth rim tape - it's really the best you
    can do without moving to a decent box section rim. a better quality
    tube might help too - that rubber has clearly crept. when seeking an
    alternative, bear in mind that most tubes these days come from similar
    factories to the one yours came from, regardless of the fancy name on
    the box.

    i'd also suggest moving to a decent wheelset, but i know the roadmaster
    is a project for you.

    Dear Jim,

    I may still be failing to make things clear, so here's a
    diagram for fixed-font.

    valve

    | | bulge1 bulge2
    | | _ - _ spoke nipple _ - _
    | |___ * - _ dent _ - - _ _ _
    - _ -

    * burst

    I should have said "spoke nipple" dent instead of "spoke
    head" dent--the heads of the spokes do not protrude at all
    from the nipples.

    Carl Fogel

    the bulges are entirely consistent with where the material will stretch
    most. decent rim tape will minimize the sharpness contour the tube
    experiences and a decent tube will not creep as much.

  19. On Sun, 15 Aug 2004 14:02:34 -0600, [email hidden]
    wrote:

    The Fury RoadMaster has outlasted its first speedometer, one
    of several inexpensive Nashbar devices bought to save time
    swapping things and to avoid remembering the quirks of
    different instruments.

    The speedometer still functioned, but the display took to
    playing optometerist games, making 0's look like 8's and 6's
    unless viewed just ever so--and sometimes even then.

    Alas, the exact same model may no longer be available
    (though what really matters is the mount and cable). And
    prices have climbed to around $15, a serious consideration
    for the $57.71 level of racing bicycle.

    WalMart to the rescue!

    I spotted a handsome red Schwinn speedometer for $9.95 and
    promptly bought it. It comes with an elaborate mount that
    can be adjusted to avoid using the speedometer as a prop
    when flipping the bike upside down, a nice touch. The mount
    also looks as if it engages the two contacts more securely
    than the other models.

    The Schwinn speedometer seems to have the same plethora of
    functions (12) as the other models, but what won my heart
    after I hooked it up and took it for a test ride up and down
    the street was that the resettable odometer reads in
    thousandths of a mile--at last, no more crude measurements
    accurate to only the nearest 53 feet!

    It's a bit startling to glance down and see the trip meter
    changing so fast, so precisely, and in such tiny increments,
    almost like switching from a 1970's typewriter to Microsoft
    Word for printing memos.

    If the Schwinn works well, I may replace the aging Nashbar
    on my road bike.

    Carl Fogel

  20. On Sun, 19 Sep 2004 17:14:39 -0600, [email hidden]

    Quoted message said:

    On Sun, 15 Aug 2004 14:02:34 -0600, [email hidden]
    wrote:

    The Fury RoadMaster has outlasted its first speedometer, one
    of several inexpensive Nashbar devices bought to save time
    swapping things and to avoid remembering the quirks of
    different instruments.

    The speedometer still functioned, but the display took to
    playing optometerist games, making 0's look like 8's and 6's
    unless viewed just ever so--and sometimes even then.

    Alas, the exact same model may no longer be available
    (though what really matters is the mount and cable). And
    prices have climbed to around $15, a serious consideration
    for the $57.71 level of racing bicycle.

    WalMart to the rescue!

    I spotted a handsome red Schwinn speedometer for $9.95 and
    promptly bought it. It comes with an elaborate mount that
    can be adjusted to avoid using the speedometer as a prop
    when flipping the bike upside down, a nice touch. The mount
    also looks as if it engages the two contacts more securely
    than the other models.

    The Schwinn speedometer seems to have the same plethora of
    functions (12) as the other models, but what won my heart
    after I hooked it up and took it for a test ride up and down
    the street was that the resettable odometer reads in
    thousandths of a mile--at last, no more crude measurements
    accurate to only the nearest 53 feet!

    It's a bit startling to glance down and see the trip meter
    changing so fast, so precisely, and in such tiny increments,
    almost like switching from a 1970's typewriter to Microsoft
    Word for printing memos.

    If the Schwinn works well, I may replace the aging Nashbar
    on my road bike.

    Carl Fogel

    The off-set mount can be centered dead ahead of the stem
    from either side--how nice!

    And speed is shown in tenths of a mile per hour, rather than
    the roughly half-mph increments on other inexpensive
    speedometers!

    Now if I can just figure out how to attach one to a basset
    hound for precision walks . . .

    Carl Fogel

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