Belt Drives - the future?

Discussion in 'UK and Europe' started by Mark T, Feb 1, 2008.

  1. Pete Biggs

    Pete Biggs Guest

    google@woodall.me.uk wrote:

    >> 2) Could the belt ever slip?

    > It looks like a toothed belt to me so no, it will never slip. (Much as
    > the cambelt on a car never slips - at least, if it does you've got a
    > very expensive problem to sort out)


    Toothing doesn't necessarily stop something slipping. Even a convential
    bike chain can slip (skip) if it's not quite matched to the sprockets.

    ~PB
     


  2. Simon Brooke

    Simon Brooke Guest

    Mark T wrote:

    > <www.bikebiz.com/news/29367/Carbon-belt-drives-are-standardised>
    >
    > Now that there's a new standard out there, does anything stand in their
    > way?


    Interested to see Gates are involved. Several of their senior management are
    in the Dumfries Cycle Club.

    --
    simon@jasmine.org.uk (Simon Brooke) http://www.jasmine.org.uk/~simon/
    ;; Drivers in the UK kill more people every single year than
    ;; Al Qaeda have ever killed worldwide in any single year.
     
  3. Rob Morley

    Rob Morley Guest

    In article <1d60lucr88z46.1r7ka7bjuqm2m$.dlg@40tude.net>, _
    jtayNOSPAMlor@hfDONTSENDMESPAMx.andara.com says...
    > On Fri, 1 Feb 2008 13:42:17 -0000, Dave Larrington wrote:
    >
    > > In news:Xns9A378326AFECDwibbled@130.133.1.4,
    > > Mark T <pleasegivegenerously@warmail*turn_up_the_heat_to_reply*.com.invalid>
    > > tweaked the Babbage-Engine to tell us:
    > >> <www.bikebiz.com/news/29367/Carbon-belt-drives-are-standardised>
    > >>
    > >> Now that there's a new standard out there, does anything stand in
    > >> their way?

    > >
    > > o Can't be retrofitted to an existing bike (or can it?)

    >
    > Oooo, yes.
    >
    > That'd have to be a design challenge; either a separable belt, a detachable
    > chainstay, or a frame made to be disposable if the belt should fail.
    >

    Proper old-fashioned bikes with full chain cases have removable seat
    stays.
     
  4. Simon Brooke

    Simon Brooke Guest

    Dave Larrington wrote:

    > In news:Xns9A378326AFECDwibbled@130.133.1.4,
    > Mark T
    > <pleasegivegenerously@warmail*turn_up_the_heat_to_reply*.com.invalid>
    > tweaked the Babbage-Engine to tell us:
    >> <www.bikebiz.com/news/29367/Carbon-belt-drives-are-standardised>
    >>
    >> Now that there's a new standard out there, does anything stand in
    >> their way?

    >
    > o Can't be retrofitted to an existing bike (or can it?)


    Probably not, because you need to be able to open up the rear triangle to
    fit it. So there needs to be some sort of openable joint, probably between
    the seat stay and the dropout.

    > o hub gears only so gear range is of necessity limited even if one can
    > afford a Rohloff


    A Rohloff has as wide a range of gears as a typical 27 speed mountain bike
    setup. You want more than that?

    --
    simon@jasmine.org.uk (Simon Brooke) http://www.jasmine.org.uk/~simon/

    ;; IE 3 is dead, but Netscape 4 still shambles about the earth,
    ;; wreaking a horrific vengeance upon the living
    ;; anonymous
     
  5. Rob Morley

    Rob Morley Guest

    In article <60h9fhF1qiqu1U2@mid.individual.net>, Simon Brooke
    simon@jasmine.org.uk says...
    > Pete Biggs wrote:
    >
    > > Mark T wrote:
    > >> <www.bikebiz.com/news/29367/Carbon-belt-drives-are-standardised>
    > >>
    > >> Now that there's a new standard out there, does anything stand in
    > >> their way?

    > >
    > > Some questions that come to mind:
    > >
    > > 1) Has it been independently tested to see if efficiency really is as
    > > high
    > > as with a conventional chain - and at high torque? Or do we just have the
    > > designer's word for it?

    >
    > The torque involved is nothing compared to the torque which these belts
    > transmit in other applications, so that isn't an issue. What is an issue,
    > as far as I'm concerned, is efficiency - I'm /highly/ sceptical as to
    > whether these things can be made as efficient as chain drive.
    >
    > Note that this isn't ever going to work with a derailleur; it's going to be
    > used with epicyclics, single speeds or fixies. Note also that the people
    > involved in the project are Nicolai (mainly interested in downhill bikes)
    > Orange (interested in mountain bikes generally but with a substantial
    > interest in downhill), and the technology specialist companies. I suspect
    > that transmission efficiency isn't that good.
    >
    > > 2) Could the belt ever slip?

    >
    > It's toothed. And it's the same technology that's used for motor engine cam
    > chain belts, which must never slip or you get very expensive damage to the
    > engine.
    >
    > > 3) How critical is belt tension? Will the usual methods of tensioning be
    > > adequate?

    >
    > About the same as for chains.
    >
    > > 4) How long will it last? Will it wear out from friction?

    >
    > In car engine applications, typically 50,000 miles at average about 3,500
    > rpm, or something like 262 million rotations of the whole chain. Or, put it
    > differently, the lifetime of several bicycles. Belts outlast chains in
    > camshaft applications by a factor of about two - and those are chains which
    > are running in an oil-bath, which ours aren't.
    >
    > > 5) What kind of sprockets will be needed, and what chainsets and hubs
    > > will they fit?

    >
    > None. You'll have to have new ones, purpose made.
    >

    I don't see why you couldn't bolt a toothed pulley to a regular
    chainset, or slide one onto a cassette hub.
     
  6. On Fri, 01 Feb 2008 13:49:45 GMT, _
    <jtayNOSPAMlor@hfDONTSENDMESPAMx.andara.com> wrote:

    >
    >My recollection is that previous versions of belt drives were estimated to
    >be less efficient that a well-lubricated new roller chain. Belts do not
    >lend themselves well to derailleur gear systems, and that would add the
    >typical lower efficiency of hub gearing.


    How about stepping out of that box: belt drive with
    expanding/contracting cylinders at the chainwheel and rear wheel? You
    get infinite gearing within the range.

    I'm sure Carl has picture of one from the 1880's.
     
  7. Pete Biggs

    Pete Biggs Guest

    Simon Brooke wrote:

    >> 2) Could the belt ever slip?

    >
    > It's toothed. And it's the same technology that's used for motor
    > engine cam chain belts, which must never slip or you get very
    > expensive damage to the engine.


    The speeds are low but the amount of torque applied by a cyclist is high.
    Some figures on how it compares to that involved in cam belts might be
    interesting.

    I noticed that it's a toothed belt, but I can imagine one skipping if there
    was a little bit too much mismatch or flexibility.

    ~PB
     
  8. On Fri, 01 Feb 2008 19:49:45 GMT, still just me
    <wheeledBobNOSPAM@yahoo.com> wrote:

    >On Fri, 01 Feb 2008 13:49:45 GMT, _
    ><jtayNOSPAMlor@hfDONTSENDMESPAMx.andara.com> wrote:
    >
    >>
    >>My recollection is that previous versions of belt drives were estimated to
    >>be less efficient that a well-lubricated new roller chain. Belts do not
    >>lend themselves well to derailleur gear systems, and that would add the
    >>typical lower efficiency of hub gearing.

    >
    >How about stepping out of that box: belt drive with
    >expanding/contracting cylinders at the chainwheel and rear wheel? You
    >get infinite gearing within the range.
    >
    >I'm sure Carl has picture of one from the 1880's.


    Dear Bob,

    Alas, belt drives for bicycles are more a modern notion.

    In early bicycling, wet and muddy roads were commonplace, but modern
    high-precision rubberized belts weren't available, so wrapping your
    belt around two pulleys and hoping that your suspenders would keep
    your pants up didn't occur to many inventors. They preferred rugged
    inch-pitch chain, not sissified half-inch stuff.

    Google the patents for bicycle and "belt drive" or "drive belt" and
    you'll find that they first appeared when bicycles began turning into
    motorcycles:
    http://www.google.com/patents?q=bicycle+"belt+drive"&scoring=2
    http://www.google.com/patents?scoring=2&q=bicycle+"drive+belt"

    Here's a typical early bike-pedal-chain on one side and
    motorcycle-engine-belt on the other side:
    http://www.nostalgic.net/pictures/1530.htm

    The relative size of the rear sprockets reminds us that bicycles gear
    up, while engine-powered vehicles gear down--even at low RPM, an
    engine turns an order of magnitude faster than legs.

    ***

    Chain, not belt, but expanding sprockets, front and rear:

    http://www.google.com/patents?id=sQJqAAAAEBAJ&printsec=abstract&zoom=4&dq=663928#PPP1,M1

    ***

    I'm not sure if the pulleys expand on this bike. In fact, I'm not sure
    what they do:
    http://www.google.com/patents?id=1rhoAAAAEBAJ&dq=519384

    That inventor did better with cycling gun barrels:
    http://www.google.com/patents?id=Sy1EAAAAEBAJ&pg=PA9&dq=502185

    http://en.wikipedia.org/wiki/Richard_Jordan_Gatling

    Cheers,

    Carl Fogel
     
  9. Rob Morley

    Rob Morley Guest

    In article <3rt6q355tjpnlfbg83usddja32rcj774n0@4ax.com>, still just me
    wheeledBobNOSPAM@yahoo.com says...
    > On Fri, 01 Feb 2008 13:49:45 GMT, _
    > <jtayNOSPAMlor@hfDONTSENDMESPAMx.andara.com> wrote:
    >
    > >
    > >My recollection is that previous versions of belt drives were estimated to
    > >be less efficient that a well-lubricated new roller chain. Belts do not
    > >lend themselves well to derailleur gear systems, and that would add the
    > >typical lower efficiency of hub gearing.

    >
    > How about stepping out of that box: belt drive with
    > expanding/contracting cylinders at the chainwheel and rear wheel? You
    > get infinite gearing within the range.
    >

    Vee belts are too inefficient compared to chains, although variomatic is
    OK with cars where convenience can be more important than efficiency.
    You could do it with a toothed belt - ISTR a chain-based system a while
    ago where the effective diameter of the chainring was regulated by the
    tension in the chain moving toothed sectors against springs.
     
  10. On Fri, 01 Feb 2008 19:49:45 GMT, still just me
    <wheeledBobNOSPAM@yahoo.com> wrote:

    >On Fri, 01 Feb 2008 13:49:45 GMT, _
    ><jtayNOSPAMlor@hfDONTSENDMESPAMx.andara.com> wrote:
    >
    >>
    >>My recollection is that previous versions of belt drives were estimated to
    >>be less efficient that a well-lubricated new roller chain. Belts do not
    >>lend themselves well to derailleur gear systems, and that would add the
    >>typical lower efficiency of hub gearing.

    >
    >How about stepping out of that box: belt drive with
    >expanding/contracting cylinders at the chainwheel and rear wheel? You
    >get infinite gearing within the range.
    >
    >I'm sure Carl has picture of one from the 1880's.

    Dear Bob,

    J.A. Little's design does have a belt drive:
    http://www.google.com/patents?id=7qNYAAAAEBAJ&pg=PA62&dq=605731

    It uses four non-expanding pulleys, but it claims great efficiency,
    possibly because there was no model to prove otherwise.

    ***

    A toothed belt lurks somewhere inside Frederic P. Bemis's fantasy:
    http://www.google.com/patents?id=qSUrAAAAEBAJ&pg=PP1&dq=617273

    Again, it probably worked so well on paper that there was no incentive
    to create a working model.

    ***

    Luther H. Wattles (charming names are part of the old patents)
    preferred the clean, simple toothed belt-drive:

    http://www.google.com/patents?id=nkRgAAAAEBAJ&pg=PP1&dq=585416#PPP1,M1

    Alas, I know of no actual belt-drive bicycles from that era, despite
    the claims of soothingly noiseless propulsion. Perhaps someone
    discovered that an oiled chain is rather quiet.

    ***

    Albert Hansel had visions of pulleys and perpetual motion that
    involved charging an impressive battery on descents and using the
    stored power to charge up the next hill:
    http://www.google.com/patents?id=bStYAAAAEBAJ&pg=PP1&dq=656323

    Like most such cranks, Albert got lost in irrelevant details, such as
    declaring his preference that the pulley-wheels be made of aluminum,
    and in even sillier fantasies, such as providing a lady's model when
    he hadn't produced the men's model.

    Again, no working model, probably because no rate of braking down the
    hill to charge the monster battery would store enough power to get
    back up to the top, since the power losses converting back and forth
    are inescapable.

    True, you could get a little feeble assistance if you were to put up
    with going downhill very slowly, but somehow such self-charging
    designs never enjoy much success outside the drawing-board and are
    practically never seen where actual hills are found.

    They always work better when freshly charged from an outlet.

    Cheers,

    Carl Fogel
     
  11. Tom Sherman

    Tom Sherman Guest

    carlfogel@comcast.net aka Carl Fogel wrote:
    > ...
    > The relative size of the rear sprockets reminds us that bicycles gear
    > up, while engine-powered vehicles gear down--even at low RPM, an
    > engine turns an order of magnitude faster than legs.
    > ...

    Mr. Fogel should be aware that large marine diesel engines operate in
    very much the same RPM range as a hominid cyclist.

    --
    Tom Sherman - Holstein-Friesland Bovinia
    "And never forget, life ultimately makes failures of all people."
    - A. Derleth
     
  12. M-gineering

    M-gineering Guest

    Simon Brooke wrote:
    >> 2) Could the belt ever slip?

    >
    > It's toothed. And it's the same technology that's used for motor engine cam
    > chain belts, which must never slip or you get very expensive damage to the
    > engine.
    >

    do you propose to make a bikeframe as stiff as an engineblock?

    >> 3) How critical is belt tension? Will the usual methods of tensioning be
    >> adequate?

    >
    > About the same as for chains.
    >

    reading the specs, it has to be much more precise


    >> 4) How long will it last? Will it wear out from friction?

    >
    > In car engine applications, typically 50,000 miles at average about 3,500
    > rpm, or something like 262 million rotations of the whole chain. Or, put it
    > differently, the lifetime of several bicycles. Belts outlast chains in
    > camshaft applications by a factor of about two - and those are chains which
    > are running in an oil-bath, which ours aren't.


    Where did you dig this up? Camshaft chains last the lifetime of the
    engine, belts you replace on a rigorous schedule

    >
    >> 6) How much will the chain and sprockets cost?

    >
    > There's no reason for it to be more expensive, except novelty -


    And the things being 10 times as wide, making them impossible to stamp
    with any precision doesn't count?


    I'd expect
    > it to be less expensive. Car camshaft belts - which is essentially what
    > these are - are not expensive.


    Don't expect a chinese knock-off for 2 ukp soon!


    --
    /Marten

    info(apestaartje)m-gineering(punt)nl
     
  13. Tim Dunne

    Tim Dunne Guest

    still just me wrote:

    > How about stepping out of that box: belt drive with
    > expanding/contracting cylinders at the chainwheel and rear wheel? You
    > get infinite gearing within the range.


    Speaking as one who works with such drives in an industrial setting, such
    devices on bicycles would be non-starters; they're hideously inefficient.

    Tim
    --
    Sent from Birmingham, UK... all about me at www.nervouscyclist.org
    'Now some people say that you shouldn't tempt fate, and for them I
    cannot disagree - but I never learned nothing by playing it safe - I
    say fate should not tempt me.' - Mary Chapin Carpenter
     
  14. In article <60gnciF1p7nj8U1@mid.individual.net>, Peter Clinch wrote:
    >
    >It is typical, but it's also changing. Hubs have come on a long way in
    >recent years while derailleurs haven't really changed /that/ much. if
    >they continue to improve (particularly the likes of the NuVinci CVT hub,
    >which just needs to get lighter AFAICT) this may start to be less of an
    >issue.


    The overall range of the NuVinci is less than a Rohloff, or than
    at least some derailleur systems. It's more than adequate for many
    uses though.
     
  15. Rob Morley

    Rob Morley Guest

    In article <fo0tkc$knl$1@localhost.localdomain>, M-gineering
    ikmotgeenspam@m-gineering.nl says...

    > And the things being 10 times as wide, making them impossible to stamp
    > with any precision doesn't count?
    >

    They'd be diecast, but you know that so why suggest stamping?
    >
    > I'd expect
    > > it to be less expensive. Car camshaft belts - which is essentially what
    > > these are - are not expensive.

    >
    > Don't expect a chinese knock-off for 2 ukp soon!
    >

    Could be amusing. :)
     
  16. In article <60glvsF1r029eU1@mid.individual.net>, Dave Larrington wrote:
    >In news:Xns9A378326AFECDwibbled@130.133.1.4,
    >Mark T <pleasegivegenerously@warmail*turn_up_the_heat_to_reply*.com.invalid>
    >tweaked the Babbage-Engine to tell us:
    >> <www.bikebiz.com/news/29367/Carbon-belt-drives-are-standardised>
    >>
    >> Now that there's a new standard out there, does anything stand in
    >> their way?

    >
    >o Can't be retrofitted to an existing bike (or can it?)


    On most bikes, not short of brazing/welding/whatever a new belt-specific
    splitable rear triangle on the drive side.


    >o hub gears only so gear range is of necessity limited even if one can
    >afford a Rohloff


    If one can afford both a Rohloff and a Schlumpf one could extend that
    range to something fairly enormous though. That's a big if though.
    But cheaper hub gears are plenty for many people.
     
  17. In article <60h9k9F1qiqu1U3@mid.individual.net>, Simon Brooke wrote:
    >Dave Larrington wrote:
    >
    >A Rohloff has as wide a range of gears as a typical 27 speed mountain bike
    >setup. You want more than that?


    http://www.sheldonbrown.com/otb.html#63speed :)
     
  18. Andrew Price

    Andrew Price Guest

    On Sat, 02 Feb 2008 06:05:14 +0100, M-gineering
    <ikmotgeenspam@m-gineering.nl> wrote:

    [---]

    >Camshaft chains last the lifetime of the
    >engine, belts you replace on a rigorous schedule


    That's true - as they get older, timing chains just get noisy. They
    are not nearly so subject to catastrophic failure as belts.
     
  19. Ben C

    Ben C Guest

    On 2008-02-02, Andrew Price <ajprice@free.fr> wrote:
    > On Sat, 02 Feb 2008 06:05:14 +0100, M-gineering
    ><ikmotgeenspam@m-gineering.nl> wrote:
    >
    > [---]
    >
    >>Camshaft chains last the lifetime of the
    >>engine, belts you replace on a rigorous schedule

    >
    > That's true - as they get older, timing chains just get noisy. They
    > are not nearly so subject to catastrophic failure as belts.


    It's true that timing chains last longer than timing belts.

    But a timing chain is fully enclosed, perfectly clean, and gets sprayed
    with oil constantly.

    A drive belt on a bicycle made out of similar stuff to car timing belts
    should last much longer than a normal non-enclosed bicycle chain.

    Even the alternator belt on a car lasts for several years and tens or
    even hundreds of thousands of miles and transfers around 10 times as
    much power as a bicycle chain.
     
  20. In article <fo0o66$d66$3@registered.motzarella.org>,
    Tom Sherman <sunsetss0003@REMOVETHISyahoo.com> wrote:

    > carlfogel@comcast.net aka Carl Fogel wrote:
    > > ...
    > > The relative size of the rear sprockets reminds us that bicycles gear
    > > up, while engine-powered vehicles gear down--even at low RPM, an
    > > engine turns an order of magnitude faster than legs.
    > > ...

    > Mr. Fogel should be aware that large marine diesel engines operate in
    > very much the same RPM range as a hominid cyclist.


    What? Each cylinder fires 1 to 1.5 Hz?

    --
    Michael Press
     
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