Re: actionbent part2

Discussion in 'Cycling Equipment' started by NYC XYZ, Apr 23, 2006.

  1. NYC XYZ

    NYC XYZ Guest

    Peter Clinch wrote:
    >
    >
    > Oh dear. I'd regard him with quite a bit of suspicion, to be
    > honest! ;-/ When testing 'bents at Ligfietswinkel in Amsterdam the
    > owner cut and remade chains as needed for customers to try bikes.
    > He had it down to about 20 seconds. Now, practice makes perfect,
    > and /I/ certainly couldn't do it that fast, but 20 minutes to
    > shorten a chain? There just isn't any excuse.


    I do (regard the mechanic hesitantly), because he seemed to be the kind
    of backyard mechanic my friends are -- "good enough for government"
    quality work: I told him there was a gold-colored link in the chain,
    but he just undid it somewhere arbitrarily, and while joining the chain
    again he didn't use the chain tool at first, but a regular
    whachamacallit, that hand-held "vice" with the scissor-like
    construction...while shortening the boom he used a rubber mallet but
    still no cloth over the bike until at my suggestion...little things
    like this.

    But, to be fair, a good quarter of the time he was struggling to get
    the chain back through the teflon tubing since the whole line slipped
    off. =) And he hadn't worked on recumbents before, so perhaps the
    novelty of it all, even though a chain is a chain is a chain, had him a
    bit distracted.

    > If the chain itself is running smoothly with no stiff links this is
    > likely to be derailleur adjustment, I'd guess.


    What's a "stiff" link?

    I'd never had a chain follow the chain ring back up, ever!

    > But again I gasp in horror... 20 minutes to shorten a chain!? :-0


    Yeah, and I'm really not exaggerating. But I am referring to the whole
    process involved, from undoing to redoing, and at least 25% of the time
    was spent trying to "thread" the chain back through the teflon tubes
    and underneath the idler (that big flywheel, right?).

    Nothing compared to 20 seconds, for sure, but certainly far better than
    I would've been able to do, not having heard of chain tools until just
    yesterday! And now, having seen it once, I at least have the framework
    against which to gauge my own attempts.

    Yep, I always knew a 'bent was gonna mean hands-on...just didn't expect
    it quite so soon!

    What's the fastest you can run yours on the flats?

    At the middle gears (front and back), I seem able only to acheive 16-17
    mph! This is what I do leisurely cruising along on my DF!!!

    I do have on them Schwalbe Marathon Plus tires, though....

    > Pete.
    > --
    > Peter Clinch Medical Physics IT Officer
    > Tel 44 1382 660111 ext. 33637 Univ. of Dundee, Ninewells Hospital
    > Fax 44 1382 640177 Dundee DD1 9SY Scotland UK
    > net [email protected] http://www.dundee.ac.uk/~pjclinch/
     
    Tags:


  2. NYC XYZ

    NYC XYZ Guest

    NYC XYZ wrote:
    >
    > <SNIP>
    >
    >
    > and while joining the chain
    > again he didn't use the chain tool at first, but a regular
    > whachamacallit, that hand-held "vice" with the scissor-like
    > construction...



    AKA "pliers."

    (How embarrassing!)
     
  3. On 23 Apr 2006 03:16:33 -0700, "NYC XYZ"
    <[email protected]> wrote:

    [snip]

    >I'd never had a chain follow the chain ring back up, ever!
    >
    >> But again I gasp in horror... 20 minutes to shorten a chain!? :-0

    >
    >Yeah, and I'm really not exaggerating. But I am referring to the whole
    >process involved, from undoing to redoing, and at least 25% of the time
    >was spent trying to "thread" the chain back through the teflon tubes
    >and underneath the idler (that big flywheel, right?).


    [snip]

    Dear N,

    It seems counter-intuitive, but one of the reasons for that
    idler pulley and those long teflon tubes is that without
    them, the chain is likely to "follow the chain ring back up"
    on the unusually long chain runs of recumbents.

    See this industrial chain troubleshooting list, which
    includes several other causes and remedies for what we call
    chain suck:

    Symptoms: The chain winds onto the sprocket (poor separation
    from the sprocket teeth.)

    Possible Causes: Span between axles is too large.

    Remedy: Install an idler.

    http://chain-guide.com/basics/7-1-6-troubleshooting.html

    Cheers,

    Carl Fogel
     
  4. Peter Clinch

    Peter Clinch Guest

    NYC XYZ wrote:

    > I do (regard the mechanic hesitantly)


    <snip>

    So why say he seems cool and you'll be back? Doesn't seem to scan...

    > What's a "stiff" link?


    Just what it says: links should move completely freely, but a stiff
    chain link has marked reluctance in pivoting relative to its neighbour.

    > Yeah, and I'm really not exaggerating. But I am referring to the whole
    > process involved, from undoing to redoing, and at least 25% of the time
    > was spent trying to "thread" the chain back through the teflon tubes
    > and underneath the idler (that big flywheel, right?).


    So we're still at 15 minutes to break a chain in a couple of places and
    pop it back together, which is still not very good.

    > What's the fastest you can run yours on the flats?


    No idea, I don't have a speedo and I'm not really that interested.

    > At the middle gears (front and back), I seem able only to acheive 16-17
    > mph! This is what I do leisurely cruising along on my DF!!!


    If you want to go faster, that's what the Speedmachine is for...

    > I do have on them Schwalbe Marathon Plus tires, though....


    Shouldn't be /that/ much slower than the plain Marathons I use. Make
    sure they're running at 100 psi.

    Pete.
    --
    Peter Clinch Medical Physics IT Officer
    Tel 44 1382 660111 ext. 33637 Univ. of Dundee, Ninewells Hospital
    Fax 44 1382 640177 Dundee DD1 9SY Scotland UK
    net [email protected] http://www.dundee.ac.uk/~pjclinch/
     
  5. NYC XYZ

    NYC XYZ Guest

    Peter Clinch wrote:
    >
    >
    > So why say he seems cool and you'll be back? Doesn't seem to scan...


    He still knows more than me! And when I say "cool," I mean that I can
    ask why he's doing something, and suggest some other way of doing
    things, and he ain't offended...very easy-going personality. I can ask
    questions, learn, and he didn't seem to mind. Of course, I keep it
    respectful, too. I don't bother him with constant questions. But I
    just get the sense I'm not dealing with a frustrated amateur racer,
    know what I mean? Who'd rather be doing the Tour de France and instead
    has to humor a dummy who has no mechanical inclinations at all....

    > Just what it says: links should move completely freely, but a stiff
    > chain link has marked reluctance in pivoting relative to its neighbour.


    Yes, I've since found a picture that "explains" it perfectly.

    > So we're still at 15 minutes to break a chain in a couple of places and
    > pop it back together, which is still not very good.


    No, I guess not...I didn't know how long it was supposed to take. But
    surely you exaggerate with your claim of 20 seconds! Fixing a flat is
    like five minutes, and surely cutting a chain (and then making sure
    it's working right thereafter) is at least five minutes, too?

    > No idea, I don't have a speedo and I'm not really that interested.


    I just hope I'm not more than 3 mph behind my DF on the flats -- bad as
    that is (a mile is like 20 NYC blocks...3 mph less would make me a
    whole neigbhorhood or two behind after an hour!).

    > If you want to go faster, that's what the Speedmachine is for...


    I seriously doubt the SpeedMachine is that much faster...it's certainly
    the same damned weight! Yes it's even more reclined, but no big deal.

    I can't wait for HP Velotechnik's new machines...I'm guessing it'll be
    another year or two....

    > Shouldn't be /that/ much slower than the plain Marathons I use. Make
    > sure they're running at 100 psi.


    Oddly enough, the tires say that maximum psi is 70-lbs.!!!

    > Pete.
    > --
    > Peter Clinch Medical Physics IT Officer
    > Tel 44 1382 660111 ext. 33637 Univ. of Dundee, Ninewells Hospital
    > Fax 44 1382 640177 Dundee DD1 9SY Scotland UK
    > net [email protected] http://www.dundee.ac.uk/~pjclinch/
     
  6. Peter Clinch

    Peter Clinch Guest

    NYC XYZ wrote:

    > No, I guess not...I didn't know how long it was supposed to take. But
    > surely you exaggerate with your claim of 20 seconds!


    I wasn't timing him, but I think that's a fair guesstimate. What you
    have to do is wind in a lever 3 times (once for each end of the break,
    once to reconnect the two ends.

    > Fixing a flat is
    > like five minutes, and surely cutting a chain (and then making sure
    > it's working right thereafter) is at least five minutes, too?


    Fixing a flat generally means removing the wheel, unseating the tyre,
    removing the inner tube, putting in a new one, reseating the tyre,
    replacing the wheel, reinflating the tyre. That's a much bigger to-do
    list than doing up lever to remove one pin, removing another, popping
    one pin back in.

    >> If you want to go faster, that's what the Speedmachine is for...

    >
    > I seriously doubt the SpeedMachine is that much faster...it's certainly
    > the same damned weight! Yes it's even more reclined, but no big deal.


    No, very big deal indeed. At 18 mph about 80% of your power is
    overcoming air resistance, and there's significantly less frontal area
    to catch the wind on a Speedmachine. There's a clue in the name!

    > Oddly enough, the tires say that maximum psi is 70-lbs.!!!


    I'd assumed, incorrectly as it turned out, that the M+ would be the same
    dimensions as the plain Marathon, but looking at the specs they are
    fatter and run at lower pressures. So they will probably be slowing you
    down :-(

    For a still reasonably puncture proof and capable touring tyre a swicth
    from the 1.75" M+ to the 1.5" Marathon running at higher pressure will
    probably help you with rolling resistance and hence speed you up.

    Pete.
    --
    Peter Clinch Medical Physics IT Officer
    Tel 44 1382 660111 ext. 33637 Univ. of Dundee, Ninewells Hospital
    Fax 44 1382 640177 Dundee DD1 9SY Scotland UK
    net [email protected] http://www.dundee.ac.uk/~pjclinch/
     
  7. NYC XYZ

    NYC XYZ Guest

    Peter Clinch wrote:
    >
    >
    > I wasn't timing him, but I think that's a fair guesstimate. What you
    > have to do is wind in a lever 3 times (once for each end of the break,
    > once to reconnect the two ends.
    >
    >
    > Fixing a flat generally means removing the wheel, unseating the tyre,
    > removing the inner tube, putting in a new one, reseating the tyre,
    > replacing the wheel, reinflating the tyre. That's a much bigger to-do
    > list than doing up lever to remove one pin, removing another, popping
    > one pin back in.


    But you've got to check the gears, too, afterwards, to make sure
    they're shifting right and all. I don't think they did too much of
    this, though...he probably checked for half a minute!

    > No, very big deal indeed. At 18 mph about 80% of your power is
    > overcoming air resistance, and there's significantly less frontal area
    > to catch the wind on a Speedmachine. There's a clue in the name!


    Now now, we all know about names and marketing...but I didn't know 80%
    of effort expended in on behalf of air resistance! Still, my point is
    that I should be at least as good as a DF, given my better aerodynamics
    on the SMGTe, but that's not been the case so far...even given my
    Schwalbe Marathon Plus tires, the hit seems too big...I can only hope
    it's a matter of developing the muscles and riding technique, as well
    as those nagging chain issues (chain hop, chain suck, stiff shifting,
    no shifting...it's rideable, but not smoothly so, especially for a new
    machine with brand new components).

    > I'd assumed, incorrectly as it turned out, that the M+ would be the same
    > dimensions as the plain Marathon, but looking at the specs they are
    > fatter and run at lower pressures. So they will probably be slowing you
    > down :-(
    >
    > For a still reasonably puncture proof and capable touring tyre a swicth
    > from the 1.75" M+ to the 1.5" Marathon running at higher pressure will
    > probably help you with rolling resistance and hence speed you up.


    Yes, I knew this going in, but I figured that I'd rather have more
    puncture-proof or puncture-resistance than speed, if the penalty isn't
    too large and way out of proportion.

    > Pete.
    > --
    > Peter Clinch Medical Physics IT Officer
    > Tel 44 1382 660111 ext. 33637 Univ. of Dundee, Ninewells Hospital
    > Fax 44 1382 640177 Dundee DD1 9SY Scotland UK
    > net [email protected] http://www.dundee.ac.uk/~pjclinch/
     
  8. Peter Clinch

    Peter Clinch Guest

    NYC XYZ wrote:

    > But you've got to check the gears, too, afterwards, to make sure
    > they're shifting right and all. I don't think they did too much of
    > this, though...he probably checked for half a minute!


    This is fair comment, but 30 seconds should be enough in the first
    instance, which still leaves us rather a lot of time. Tweaking the
    gears is easy enough with the adjuster screw where the gear cable
    goes into the rear mech, just needs the odd tweak to tune the shifting.

    > Now now, we all know about names and marketing...but I didn't know 80%
    > of effort expended in on behalf of air resistance!


    That is, IIRC, the approximate figure on a DF, though I can't
    remember if that's on the hoods, in a heavy tuck or what. But it
    does show approximately the degree to which speed is dominated by
    aerodynamics any time you get any sort of fast.

    > Still, my point is
    > that I should be at least as good as a DF, given my better aerodynamics
    > on the SMGT


    They're not /that/ much better. I have my seat reclined as far as
    possible and it's pretty clear that cycling with pals on DF leaned
    over the drops that the frontal area catching the wind isn't all
    that different. When they go into a full speed crouch it's quite
    obvious they have less frontal area than me.
    If you want better aero, that's what the Speedmachine is for (and
    to some extent, the Grasshopper).

    > Yes, I knew this going in, but I figured that I'd rather have more
    > puncture-proof or puncture-resistance than speed, if the penalty isn't
    > too large and way out of proportion.


    To put the dangers into perspective, I've had 2 punctures on mine
    in 5 years running standard Marathons. They give very good
    puncture resistance. The M+ is only really an issue if you're in
    Puncture Hell, otherwise they'd be standard issue rather than the
    plain Marathon.

    Pete.
    --
    Peter Clinch Medical Physics IT Officer
    Tel 44 1382 660111 ext. 33637 Univ. of Dundee, Ninewells Hospital
    Fax 44 1382 640177 Dundee DD1 9SY Scotland UK
    net [email protected] http://www.dundee.ac.uk/~pjclinch/
     
  9. Peter Clinch wrote:
    > NYC XYZ wrote:


    [snip]

    > > Now now, we all know about names and marketing...but I didn't know 80%
    > > of effort expended in on behalf of air resistance!

    >
    > That is, IIRC, the approximate figure on a DF, though I can't
    > remember if that's on the hoods, in a heavy tuck or what. But it
    > does show approximately the degree to which speed is dominated by
    > aerodynamics any time you get any sort of fast.
    >
    > > Still, my point is
    > > that I should be at least as good as a DF, given my better aerodynamics
    > > on the SMGT

    >
    > They're not /that/ much better. I have my seat reclined as far as
    > possible and it's pretty clear that cycling with pals on DF leaned
    > over the drops that the frontal area catching the wind isn't all
    > that different. When they go into a full speed crouch it's quite
    > obvious they have less frontal area than me.
    > If you want better aero, that's what the Speedmachine is for (and
    > to some extent, the Grasshopper).


    [snip]

    Dear N & Peter,

    It's common to assume that recumbents have an aerodynamic advantage
    over the traditional diamond frame, but the advantage is actually
    limited to fairly extreme recumbents.

    You can see some of the surprising details on this speed calculator
    page:

    http://www.kreuzotter.de/english/espeed.htm

    Hovering the mouse over the radio button for the type of recumbent will
    pop up a picture that gives an idea of what a particular model looks
    like. After selecting a model, clicking on calculate at the bottom will
    give a predicted speed for the default values and the drag area used
    for the calculation.

    mph frontal type
    17.1 4.3433 recumbent long wheel base
    17.3 4.7889 df hands on tops
    18.5 3.3781 recumbent short wheel base
    19.4 3.2559 df hands on drops
    20.5 2.7111 df triathlon bars
    21.2 2.1748 recumbent short wheel base racer
    22.3 2.0397 df superman position
    23.1 1.5504 recumbent lowracer

    Obviously, these are idealized guides to what a particular bike and
    rider will do, with different tires and transmission efficiences
    affecting things. But for the same rider and power, it takes a
    recumbent that stresses speed instead of comfort to improve on the
    aerodynamics of an ordinary diamond frame:

    http://www.bicycleman.com/history/images/1933hour-record_lg.jpg

    Cheers,

    Carl Fogel
     
  10. Peter Clinch

    Peter Clinch Guest

    [email protected] wrote:

    > You can see some of the surprising details on this speed calculator
    > page:
    >
    > http://www.kreuzotter.de/english/espeed.htm


    Thanks for that link, Carl.

    > Hovering the mouse over the radio button for the type of recumbent will
    > pop up a picture that gives an idea of what a particular model looks
    > like.


    Note for this discussion that a Speedmachine would probably be somewhat
    better than the "ShortWheelBase, above seat steering, racing equipped"
    but not as good as "Lowracer, above seat steering". That assumes it's
    the ASS SpM rather than the new USS option.

    Pete.
    --
    Peter Clinch Medical Physics IT Officer
    Tel 44 1382 660111 ext. 33637 Univ. of Dundee, Ninewells Hospital
    Fax 44 1382 640177 Dundee DD1 9SY Scotland UK
    net [email protected] http://www.dundee.ac.uk/~pjclinch/
     
  11. Jon  Meinecke

    Jon Meinecke Guest

    <[email protected]> wrote in message>
    > It's common to assume that recumbents have an aerodynamic advantage
    > over the traditional diamond frame, but the advantage is actually
    > limited to fairly extreme recumbents.
    >
    > You can see some of the surprising details on this speed calculator
    > page:
    >
    > http://www.kreuzotter.de/english/espeed.htm


    "It's not about the bike."

    You're correct that the differences are not as large as people
    might imagine. People who try a recumbent and think they will
    automatically be 10-20% faster *will be* disappointed. It depends
    on what you're comparing, but 3-7% without going"extreme"
    is quite possible, however.

    Note that the default tire choices on the kreuzotter website for
    non-race configured recumbents are medium and wide. The df
    tire choices are all high pressure, by default. Here's the list
    with the high-pressure tire choices for the LWB and SWB
    added**.

    mph frontal type
    17.1 4.3433 recumbent long wheel base (medium slick tires)
    17.3 4.7889 df hands on tops
    18.0 3.8777 recumbent long wheel base (high-pressure tires)**
    18.5 3.3781 recumbent short wheel base (wide slick tires)
    19.4 3.2559 df hands on drops
    19.5 2.8408 recumbent short wheel base (high pressure tires)**
    20.5 2.7111 df triathlon bars
    21.2 2.1748 recumbent short wheel base racer
    22.3 2.0397 df superman position
    23.1 1.5504 recumbent lowracer

    It's also worth noting that the two non-race configured recumbents
    modeled above are under seat steering. Most recumbent bikes in
    the US are above seat steering. The "recumbent short wheel base
    racer" may cover many of the so-called "high racer" recumbents
    (Bacchetta, Volae, RANS...) and these may not be considered
    "extreme" or sacrificing of comfort.

    Jon Meinecke
     
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