Fixed gear conversion questions

Discussion in 'Cycling Equipment' started by Bruni, May 7, 2004.

  1. Bruni

    Bruni Guest

    Spacers come off the right, go on left, then re true. Chain tensioners won't
    work with a fixie, rather a single speed. I altered one vert DO bike with an
    Eccentric BB insert but not cheap @ $150. DO replacement is $120. If you
    don't get a true track hub, max hold thread lock and a conventional lockring
    can work.
    Tom

    --
    Bruni Bicycles
    "Where art meets science"
    brunibicycles.com
    410.426.3420
    Michael Press <[email protected]> wrote in message
    news:[email protected]
    >
    > I'm going to convert my old 7-speed road bike to fixed gear. I want
    > to do it as cheaply as possible; if I really enjoy it I'll spend more
    > later or get a "real" fixed gear bike.
    >
    > From reading Sheldon's fixed gear pages (excellent as usual) it seems
    > I only need:
    > * A fixed gear sprocket (it'll thread into my freewheel hub)
    > * A chain tensioner (like the Surly Singelator) since the bike has
    > vertical dropouts
    >
    > Optionally I may also get
    > * A new chain as recommended by Sheldon
    > * Short stack chainring bolts so I can remove the big ring
    >
    > And I'll have to re-dish the rear wheel. I'll remove the derailleurs,
    > shifter and cables, but leave both brakes on.
    >
    > I have a couple of questions though:
    > 1) How do I set or adjust the chainline since the chainring is in a
    > fixed position and the sprocket is fixed to the hub? The only thing I
    > can think of is change the wheel dish, but that doesn't seem right.
    > 2) Sheldon seems to say that chain tensioners will break if you apply
    > rearward pedal pressure, but it's not completely clear. Is this really
    > true? Seems like not being able to brake by pedal pressure would take
    > alot of the fun out of a fixie.
    > 3) Any opinions on the $30 Pyramid chain tensioner vs. the $50 Surly
    > Singelator?
    >
    > Any other comments or suggestions on this project are welcomed.
    >
    > Thanks,
    > Michael
     
    Tags:


  2. I'm going to convert my old 7-speed road bike to fixed gear. I want
    to do it as cheaply as possible; if I really enjoy it I'll spend more
    later or get a "real" fixed gear bike.

    From reading Sheldon's fixed gear pages (excellent as usual) it seems
    I only need:
    * A fixed gear sprocket (it'll thread into my freewheel hub)
    * A chain tensioner (like the Surly Singelator) since the bike has
    vertical dropouts

    Optionally I may also get
    * A new chain as recommended by Sheldon
    * Short stack chainring bolts so I can remove the big ring

    And I'll have to re-dish the rear wheel. I'll remove the derailleurs,
    shifter and cables, but leave both brakes on.

    I have a couple of questions though:
    1) How do I set or adjust the chainline since the chainring is in a
    fixed position and the sprocket is fixed to the hub? The only thing I
    can think of is change the wheel dish, but that doesn't seem right.
    2) Sheldon seems to say that chain tensioners will break if you apply
    rearward pedal pressure, but it's not completely clear. Is this really
    true? Seems like not being able to brake by pedal pressure would take
    alot of the fun out of a fixie.
    3) Any opinions on the $30 Pyramid chain tensioner vs. the $50 Surly
    Singelator?

    Any other comments or suggestions on this project are welcomed.

    Thanks,
    Michael
     
  3. Michael Press wrote:

    > I'm going to convert my old 7-speed road bike to fixed gear. I want
    > to do it as cheaply as possible; if I really enjoy it I'll spend more
    > later or get a "real" fixed gear bike.
    >
    > From reading Sheldon's fixed gear pages (excellent as usual) it seems
    > I only need:
    > * A fixed gear sprocket (it'll thread into my freewheel hub)
    > * A chain tensioner (like the Surly Singelator) since the bike has
    > vertical dropouts


    Nope, you need to re-read the articles. Chain tensioners cannot be used
    with fixed gears, only with coastie singlespeeds.

    > Optionally I may also get
    > * A new chain as recommended by Sheldon
    > * Short stack chainring bolts so I can remove the big ring
    >
    > And I'll have to re-dish the rear wheel. I'll remove the derailleurs,
    > shifter and cables, but leave both brakes on.
    >
    > I have a couple of questions though:
    > 1) How do I set or adjust the chainline since the chainring is in a
    > fixed position and the sprocket is fixed to the hub? The only thing I
    > can think of is change the wheel dish, but that doesn't seem right.


    The chainline is adjusted by re-arranging spacer washers on the rear
    axle, moving some from the right side to the left side, so the hub shell
    (and sprocket) moves to the right.

    Once you have adjusted the chain line, you will then need to re-dish the
    wheel to bring the rim back to the center of the bike.

    > 2) Sheldon seems to say that chain tensioners will break if you apply
    > rearward pedal pressure, but it's not completely clear.


    Gee, I wrote:

    "Note! Chain tensioners cannot be used with fixed-gear or coaster brake
    systems!"

    I printed that in boldface red type, and italicized "cannot."

    What part of that was not completely clear? Should I have used a bigger
    font? Underlined? A handful of exclamation points?

    > Is this really true?


    Naw, I am in the habit of lying about bicycle safety issues, because I
    own a lot of hospital stock. I guess you caught me! ;-)

    > Seems like not being able to brake by pedal pressure would take
    > alot of the fun out of a fixie.


    Not just a matter of "fun", it's a matter of safety. A chain tensioner
    WON'T WORK with a fixed gear, and as a result, the chain will likely
    fall off. This is dangerous on a fixed gear.

    > 3) Any opinions on the $30 Pyramid chain tensioner vs. the $50 Surly
    > Singelator?


    The Pyramid is very similar to the original Singleator, but the newer
    Singleator is nicer, but currently unavailable--waiting for a new
    production run.

    Singlespeed chain tensioners, even the best of them, are ugly kludges,
    and they CANNOT BE USED FOR FIXED GEARS.

    If you want to singlize a bike with vertical dropouts, the White
    Industries eccentric hub is a vastly superior solution, well worth what
    it costs. http://sheldonbrown.com/harris/white-hubs

    Sheldon "Trying To Be Clear" Brown
    +----------------------------------------------------------------+
    | The thing about the cold is that you can never tell how cold |
    | it is from looking out a kitchen window. You have to dress |
    | up, get out training and when you come back, you then know |
    | how cold it is. -Sean Kelly |
    +----------------------------------------------------------------+
    Harris Cyclery, West Newton, Massachusetts
    Phone 617-244-9772 FAX 617-244-1041
    http://harriscyclery.com
    Hard-to-find parts shipped Worldwide
    http://captainbike.com http://sheldonbrown.com
     
  4. Werehatrack

    Werehatrack Guest

    On Fri, 07 May 2004 09:26:25 -0400, Michael Press
    <[email protected]> may have said:

    >Any other comments or suggestions on this project are welcomed.


    Given that you're probably going to have to spend upwards of $175 for
    a hub, sprocket, spacers and such, perhaps this would be a good time
    to cast around through the used bike supply to see if there's one
    which has more useful dropouts...and convert *that*, instead. You'll
    likely spend less, and you'll still have the old roadie available to
    ride as well.

    --
    My email address is antispammed; pull WEEDS if replying via e-mail.
    Typoes are not a bug, they're a feature.
    Words processed in a facility that contains nuts.
     
  5. toolguy

    toolguy Guest

    >>
    >> And I'll have to re-dish the rear wheel. I'll remove the derailleurs,
    >> shifter and cables, but leave both brakes on.
    >>


    >Once you have adjusted the chain line, you will then need to re-dish the
    >wheel to bring the rim back to the center of the bike.
    >


    If you're using an existing hub/wheel for the conversion to a fixie
    and assuming this wheel is already set up for the frame to be used as
    the fixie, then wouldn't it be correctly spaced for the frame and
    already be dished? Re dishing implies you've changed the axle
    distance and then it wouldn't fit the frame anymore unless you tweak
    the frame. Am I missing something??

    Neil
     
  6. Someone wrote:

    >>>And I'll have to re-dish the rear wheel. I'll remove the derailleurs,
    >>>shifter and cables, but leave both brakes on.
    >>>

    I replied, in part:
    >
    >>Once you have adjusted the chain line, you will then need to re-dish the
    >>wheel to bring the rim back to the center of the bike.


    The anonymous "Tool Guy" wrote:

    > If you're using an existing hub/wheel for the conversion to a fixie
    > and assuming this wheel is already set up for the frame to be used as
    > the fixie,


    But it isn't. He's talking about converting a derailer bike, using the
    original rear wheel.

    > then wouldn't it be correctly spaced for the frame and
    > already be dished? Re dishing implies you've changed the axle
    > distance and then it wouldn't fit the frame anymore unless you tweak
    > the frame. Am I missing something??


    Yes, you are. The original poster was talking about modifying his or
    her original derailer-type wheel, which would have the freewheel threads
    too close to the centerline of the frame for good chainline.

    I explained that he would have to rearrange spacers by moving some from
    the right side to the left side (but leaving the total thickness the
    same) so as to move the hub shell to the right, until the fixed sprocket
    would line up properly with the chainring.

    This operation would also move the rim to the right, so the dish would
    then be incorrect. The dish would then need to be corrected by
    tightening spokes on the left side to bring the rim back to the
    centerline of the frame.

    Sheldon "Having Trouble Making Myself Clear Today" Brown
    +------------------------------------+
    | Experience is a hard teacher, |
    | because she gives the test first, |
    | the lesson after. -- Vernon Law |
    +------------------------------------+
    Harris Cyclery, West Newton, Massachusetts
    Phone 617-244-9772 FAX 617-244-1041
    http://harriscyclery.com
    Hard-to-find parts shipped Worldwide
    http://captainbike.com http://sheldonbrown.com
     
  7. Sheldon Brown <[email protected]> wrote:
    >
    >Once you have adjusted the chain line, you will then need to re-dish the
    >wheel to bring the rim back to the center of the bike.


    I was assuming I would re-dish first. Now I understand.

    >> 2) Sheldon seems to say that chain tensioners will break if you apply
    >> rearward pedal pressure, but it's not completely clear.

    >
    >Gee, I wrote:
    >"Note! Chain tensioners cannot be used with fixed-gear or coaster brake
    >systems!"
    >I printed that in boldface red type, and italicized "cannot."
    >What part of that was not completely clear? Should I have used a bigger
    >font? Underlined? A handful of exclamation points?


    I never saw that quote - it's on the singlespeed page, not the fixie
    or fixie conversion pages. I was referrring to this quote on the
    fixie-conversion page:

    "You cannot use a derailer on a fixed gear bike, even as a chain
    tensioner, because when you resist the rotation of the pedals, you
    would bend the derailer. This presents a problem if you want to use a
    frame with vertical dropouts as a fixed gear, because there's no easy
    way to adjust the chain tension. This is also true of chain tensioners
    sold for singlespeed coasting bikes, such as the Surly Singleator."

    To me, this wasn't clear. Certainly the red bold warning on the
    singlespeed page is clear. I suggest adding that to the
    fixie-conversion page since that's where fixie-newbies like myself
    would be reading.

    >> Is this really true?

    >
    >Naw, I am in the habit of lying about bicycle safety issues, because I
    >own a lot of hospital stock. I guess you caught me! ;-)


    I guess I was really asking for more detail or other ideas and didn't
    word it right. I don't intuively understand why backpressure on the
    chain would bend a derailleur or chain tensioner.

    >> Seems like not being able to brake by pedal pressure would take
    >> alot of the fun out of a fixie.

    >
    >Not just a matter of "fun", it's a matter of safety. A chain tensioner
    >WON'T WORK with a fixed gear, and as a result, the chain will likely
    >fall off. This is dangerous on a fixed gear.
    >
    >Singlespeed chain tensioners, even the best of them, are ugly kludges,
    >and they CANNOT BE USED FOR FIXED GEARS.


    I think I've got it now ;-)

    Thanks,
    Michael
     
  8. toolguy

    toolguy Guest

    On Fri, 07 May 2004 11:34:29 -0400, Sheldon Brown
    <[email protected]> wrote:

    >Someone wrote:
    >
    >>>>And I'll have to re-dish the rear wheel. I'll remove the derailleurs,
    >>>>shifter and cables, but leave both brakes on.
    >>>>

    >I replied, in part:
    >>
    >>>Once you have adjusted the chain line, you will then need to re-dish the
    >>>wheel to bring the rim back to the center of the bike.

    >
    >The anonymous "Tool Guy" wrote:


    Why am I anonymous? My name on the wreck is Toolguy and I signed it
    with my real name, Neil.

    >
    >> If you're using an existing hub/wheel for the conversion to a fixie
    >> and assuming this wheel is already set up for the frame to be used as
    >> the fixie,

    >
    >But it isn't. He's talking about converting a derailer bike, using the
    >original rear wheel.
    >
    >> then wouldn't it be correctly spaced for the frame and
    >> already be dished? Re dishing implies you've changed the axle
    >> distance and then it wouldn't fit the frame anymore unless you tweak
    >> the frame. Am I missing something??

    >
    >Yes, you are. The original poster was talking about modifying his or
    >her original derailer-type wheel, which would have the freewheel threads
    >too close to the centerline of the frame for good chainline.
    >
    >I explained that he would have to rearrange spacers by moving some from
    >the right side to the left side (but leaving the total thickness the
    >same) so as to move the hub shell to the right, until the fixed sprocket
    >would line up properly with the chainring.
    >
    >This operation would also move the rim to the right, so the dish would
    >then be incorrect. The dish would then need to be corrected by
    >tightening spokes on the left side to bring the rim back to the
    >centerline of the frame.



    Got it now. Thanks. Not having done this before, I was interpreting
    the spacing on the freewheel threads (spacing the cog on the freewheel
    threads instead of the axle). It makes perfect sense now. Thanks
    for the clarification.

    Neil (aka Toolguy)
     
  9. Erik Brooks

    Erik Brooks Guest

    Sheldon Brown <[email protected]> wrote in message news:<[email protected]>...
    >
    > If you want to singlize a bike with vertical dropouts, the White
    > Industries eccentric hub is a vastly superior solution, well worth what
    > it costs. http://sheldonbrown.com/harris/white-hubs
    >
    > Sheldon "Trying To Be Clear" Brown


    Sheldon,
    So does this also mean that if you want to use a flip-flop hub, with
    fixed on one side and SS on the other, and a frame with vertical
    drop-outs, that you MUST use this eccentric hub?

    Thanks,
    Erik Brooks
     
  10. Erik Brooks wrote:

    I wrote:

    >>If you want to singlize a bike with vertical dropouts, the White
    >>Industries eccentric hub is a vastly superior solution, well worth what
    >>it costs. http://sheldonbrown.com/harris/white-hubs
    >>
    >>Sheldon "Trying To Be Clear" Brown

    >

    Erik Brooks asked:

    > Sheldon,
    > So does this also mean that if you want to use a flip-flop hub, with
    > fixed on one side and SS on the other, and a frame with vertical
    > drop-outs, that you MUST use this eccentric hub?
    >

    Yep.

    They're swell hubs, I like mine a lot. http://sheldonbrown.org/rambouillet

    Sheldon "Eccentric" Brown
    +-------------------------------------------------+
    | Search the Quality Bicycle Products Catalog |
    | and order on line: |
    | http://sheldonbrown.com/quality |
    +-------------------------------------------------+
    Harris Cyclery, West Newton, Massachusetts
    Phone 617-244-9772 FAX 617-244-1041
    http://harriscyclery.com
    Hard-to-find parts shipped Worldwide
    http://captainbike.com http://sheldonbrown.com
     
  11. Jeff Wills

    Jeff Wills Guest

    Werehatrack <[email protected]> wrote in message news:<[email protected]>...
    > On Fri, 07 May 2004 09:26:25 -0400, Michael Press
    > <[email protected]> may have said:
    >
    > >Any other comments or suggestions on this project are welcomed.

    >
    > Given that you're probably going to have to spend upwards of $175 for
    > a hub, sprocket, spacers and such, perhaps this would be a good time
    > to cast around through the used bike supply to see if there's one
    > which has more useful dropouts...and convert *that*, instead. You'll
    > likely spend less, and you'll still have the old roadie available to
    > ride as well.


    True. A couple weeks back, I spied a nice road frame & fork of
    indeterminate origin (good workmanship, Campy horizontal dropouts) for
    $50 at the local used bike emporium: Citybikes in Portland, Oregon.

    I built a single-speeder around a Raleigh frame that was given to me-
    about $35 for the fork and then I scrounged from my pile. Total bill
    came to $65, I think.

    Jeff
     
  12. On Fri, 07 May 2004 09:26:25 -0400, Michael Press wrote:

    >
    > I'm going to convert my old 7-speed road bike to fixed gear. I want
    > to do it as cheaply as possible; if I really enjoy it I'll spend more
    > later or get a "real" fixed gear bike.
    >
    > From reading Sheldon's fixed gear pages (excellent as usual) it seems
    > I only need:
    > * A fixed gear sprocket (it'll thread into my freewheel hub)
    > * A chain tensioner (like the Surly Singelator) since the bike has
    > vertical dropouts


    No, don't do this. Find another frame. A vertical-dropout frame is not
    a good idea for a fixed gear, nor is a chain tensioner. Back-pressure
    will over-stress that chain tensioner very easily.

    > I have a couple of questions though:
    > 1) How do I set or adjust the chainline since the chainring is in a
    > fixed position and the sprocket is fixed to the hub? The only thing I
    > can think of is change the wheel dish, but that doesn't seem right. 2)
    > Sheldon seems to say that chain tensioners will break if you apply
    > rearward pedal pressure, but it's not completely clear. Is this really
    > true? Seems like not being able to brake by pedal pressure would take
    > alot of the fun out of a fixie.


    It is true. Most, but not all, of those chain tensioners are sprung.
    Back pressure will tighten up that spring -- and probably bottom it out.
    Meanwhile the top run of chain will go slack, causing concerns about
    dropping the chain. If it is not sprung, it still is a bad idee.
    Back-pressure puts a lot of force on something not meant to handle it.

    --

    David L. Johnson

    __o | the people can always be brought to the bidding of the leaders.
    _`\(,_ | That is easy. All you have to do is tell them they are being
    (_)/ (_) | attacked, and denounce the peacemakers for lack of patriotism
    and exposing the country to danger. It works the same in any
    <country. -- Hermann Goering
     
  13. On Fri, 07 May 2004 14:48:49 +0000, Werehatrack wrote:
    > Given that you're probably going to have to spend upwards of $175 for
    > a hub, sprocket, spacers and such, perhaps this would be a good time
    > to cast around through the used bike supply to see if there's one
    > which has more useful dropouts...and convert *that*, instead. You'll
    > likely spend less, and you'll still have the old roadie available to
    > ride as well.


    $175?!? How much is that White Industries hub again?

    A Dura-Ace cog is only like $20 and a lockring is maybe $8. If you ask
    nicely, most shops will give you a handful of spacers when you buy a hub
    or just about anything else.

    EK
     
  14. A Muzi

    A Muzi Guest

    Michael Press wrote:
    > I'm going to convert my old 7-speed road bike to fixed gear. I want
    > to do it as cheaply as possible; if I really enjoy it I'll spend more
    > later or get a "real" fixed gear bike.
    >
    > From reading Sheldon's fixed gear pages (excellent as usual) it seems
    > I only need:
    > * A fixed gear sprocket (it'll thread into my freewheel hub)
    > * A chain tensioner (like the Surly Singelator) since the bike has
    > vertical dropouts
    >
    > Optionally I may also get
    > * A new chain as recommended by Sheldon
    > * Short stack chainring bolts so I can remove the big ring
    >
    > And I'll have to re-dish the rear wheel. I'll remove the derailleurs,
    > shifter and cables, but leave both brakes on.
    >
    > I have a couple of questions though:
    > 1) How do I set or adjust the chainline since the chainring is in a
    > fixed position and the sprocket is fixed to the hub? The only thing I
    > can think of is change the wheel dish, but that doesn't seem right.
    > 2) Sheldon seems to say that chain tensioners will break if you apply
    > rearward pedal pressure, but it's not completely clear. Is this really
    > true? Seems like not being able to brake by pedal pressure would take
    > alot of the fun out of a fixie.
    > 3) Any opinions on the $30 Pyramid chain tensioner vs. the $50 Surly
    > Singelator?


    Although a vertical-end bike can be made functional as a
    single speed by adding a chain tensioner (and no, there
    isn't much difference between those) fixed is another thing
    entirely.

    The forces involved are enough to wreck a derailleur or
    tensioner ( and a used derailleur, free, does the same job
    as your $30 fashion item).

    Why not keep your eye out for a used road frame with normal
    horizontal ends? Or if you love your bike, give it a little
    plastic surgery:
    http://www.yellowjersey.org/trakends.html

    To adjust chainline on a fixed hub, move the crank in with
    the appropriate )shorter) spindle. Most classic spindles are
    asymmetric and reversible.

    With a road freewheel hub*, your cog ends up pretty far
    inside. You can move axle spacers from the right to the
    left, as you surmised, and recenter the rim over the
    locknuts. Your wheel will end up with more even tension.

    *We've had this discussion to death, and I can't add
    anything new, but you might review previous threads here
    about a fixed cog on a hub without a proper reversed
    lockring. YMMV.
    --
    Andrew Muzi
    www.yellowjersey.org
    Open every day since 1 April, 1971
     
  15. A Muzi

    A Muzi Guest

    >>>And I'll have to re-dish the rear wheel. I'll remove the derailleurs,
    >>>shifter and cables, but leave both brakes on.


    >>Once you have adjusted the chain line, you will then need to re-dish the
    >>wheel to bring the rim back to the center of the bike.


    toolguy wrote:
    > If you're using an existing hub/wheel for the conversion to a fixie
    > and assuming this wheel is already set up for the frame to be used as
    > the fixie, then wouldn't it be correctly spaced for the frame and
    > already be dished? Re dishing implies you've changed the axle
    > distance and then it wouldn't fit the frame anymore unless you tweak
    > the frame. Am I missing something??


    While a derailleur system handles the 52-26 combination
    complainingly, a fixed-length chain wouldn't like that as much.
    We're assuming his wheel is spaced for a seven freewheel but
    has only one cog now. Hence the "respace/redish" advice.
    --
    Andrew Muzi
    www.yellowjersey.org
    Open every day since 1 April, 1971
     
  16. Werehatrack

    Werehatrack Guest

    On Fri, 07 May 2004 17:50:37 -0700, Elmo Spam King
    <[email protected]> may have said:

    >
    >On Fri, 07 May 2004 14:48:49 +0000, Werehatrack wrote:
    >> Given that you're probably going to have to spend upwards of $175 for
    >> a hub, sprocket, spacers and such, perhaps this would be a good time
    >> to cast around through the used bike supply to see if there's one
    >> which has more useful dropouts...and convert *that*, instead. You'll
    >> likely spend less, and you'll still have the old roadie available to
    >> ride as well.

    >
    >$175?!? How much is that White Industries hub again?


    Around $160. I've never seen one in a shop, though. I suspect that
    the local shops don't get much demand for fixie stuff, which is
    reflected by the fact that to date, I have seen a grand total of one
    fixie being ridden in this immediate area. You would think that our
    relatively flat terrain would be prime territory for this type of
    unit, but I suspect the prospect of Thou Shalt Pedal When Moving is an
    unappetizing "feature" for our warm summers.

    >A Dura-Ace cog is only like $20 and a lockring is maybe $8. If you ask
    >nicely, most shops will give you a handful of spacers when you buy a hub
    >or just about anything else.


    The ones that have them, that is. We seem to have sprouted a number
    of shops whose stock of fiddly bits is limited, sparse or nearly
    nonexistent...and a couple that are almost aggressively
    anticooperative about supplying what I see as really common repair
    items. We also have some that are very accommodating, helpful,
    well-stocked and/or willing to get whatever the customer needs, and
    not rapaciously priced. It's not hard to predict the effect that this
    has had on my shopping habits.

    --
    My email address is antispammed; pull WEEDS if replying via e-mail.
    Typoes are not a bug, they're a feature.
    Words processed in a facility that contains nuts.
     
  17. michael-<< I'm going to convert my old 7-speed road bike to fixed gear. I want
    to do it as cheaply as possible; if I really enjoy it I'll spend more
    later or get a "real" fixed gear bike.

    From reading Sheldon's fixed gear pages (excellent as usual) it seems
    I only need:
    * A fixed gear sprocket (it'll thread into my freewheel hub)
    * A chain tensioner (like the Surly Singelator) >><BR><BR>


    DO NOT use a chain tensioner with a fixed gear. You run the risk of a ripping
    it off the bike...Go single speed(BMX freewheel) but not fixed!!

    Peter Chisholm
    Vecchio's Bicicletteria
    1833 Pearl St.
    Boulder, CO, 80302
    (303)440-3535
    http://www.vecchios.com
    "Ruote convenzionali costruite eccezionalmente bene"
     
  18. On 2004-05-08, Qui si parla Campagnolo <[email protected]> wrote:
    > michael-<< I'm going to convert my old 7-speed road bike to fixed gear. I want
    > to do it as cheaply as possible; if I really enjoy it I'll spend more
    > later or get a "real" fixed gear bike.
    >
    > From reading Sheldon's fixed gear pages (excellent as usual) it seems
    > I only need:
    > * A fixed gear sprocket (it'll thread into my freewheel hub)
    > * A chain tensioner (like the Surly Singelator) >><BR><BR>
    >
    >
    > DO NOT use a chain tensioner with a fixed gear. You run the risk of a ripping
    > it off the bike...Go single speed(BMX freewheel) but not fixed!!
    >
    > Peter Chisholm
    > Vecchio's Bicicletteria
    > 1833 Pearl St.
    > Boulder, CO, 80302
    > (303)440-3535
    > http://www.vecchios.com
    > "Ruote convenzionali costruite eccezionalmente bene"


    As Peter said, don't use a chain tensioner. They're not designed
    to resist the force when you resist the motion of the pedals
    (back pedal). Depending on how horizontal the drop-outs are on
    your bicycle bicycle, you may be able to get the chain tight without one.

    You'll also need a 'retaining system' of some kind. You can Loctite a
    bottom bracket lockring overtop of the cog, to prevent it from
    unthreading when you 'back pedal'. If you're going brakeless, seriously
    consider getting a track hub.

    Cheers

    Cam
     
  19. [email protected]lnet wrote:

    >You'll also need a 'retaining system' of some kind. You can Loctite a
    >bottom bracket lockring overtop of the cog, to prevent it from
    >unthreading when you 'back pedal'. If you're going brakeless, seriously
    >consider getting a track hub.


    Yes, I'd prefer a lockring even though I'll keep the brake(s). I've
    also discovered since my original post that the bike actually has
    "semi-horizontal" dropouts - much closer to horizontal than vertical,
    so I'm defintely going forward with this.

    Can you give more detail on this - what's a bottom bracket lockring?
    Is that from an old-style bottom bracket? I recall the last BB I
    installed (a few years ago), a cartridge-type, each half of the BB
    screwed in on opposite sides, but I don't recall a lockring. Can this
    still be bought or do you have to scavenge an old BB?

    Also, does the lockring screw into the hub threads after the cog? If
    not, what do you mean by Locktiting "overtop of the cog"?

    Thanks,
    Michael
     
  20. On 2004-05-10, Michael Press <[email protected]> wrote:
    > [email protected]lnet wrote:
    >
    >>You'll also need a 'retaining system' of some kind. You can Loctite a
    >>bottom bracket lockring overtop of the cog, to prevent it from
    >>unthreading when you 'back pedal'. If you're going brakeless, seriously
    >>consider getting a track hub.

    >
    > Yes, I'd prefer a lockring even though I'll keep the brake(s). I've
    > also discovered since my original post that the bike actually has
    > "semi-horizontal" dropouts - much closer to horizontal than vertical,
    > so I'm defintely going forward with this.
    >
    > Can you give more detail on this - what's a bottom bracket lockring?
    > Is that from an old-style bottom bracket? I recall the last BB I
    > installed (a few years ago), a cartridge-type, each half of the BB
    > screwed in on opposite sides, but I don't recall a lockring. Can this
    > still be bought or do you have to scavenge an old BB?
    >
    > Also, does the lockring screw into the hub threads after the cog? If
    > not, what do you mean by Locktiting "overtop of the cog"?
    >
    > Thanks,
    > Michael
    >


    Yes, the bottom bracket lockring is from the old-style bottom bracket.
    Check out Sheldon Brown's excellent guide to conversions at
    http://www.sheldonbrown.com/fixed-conversion.html
    With the orientation of the dropouts, you can probably get good chain
    tension. You could also use a "half-link" in the chain, which is a short
    link that allows more flexibility than standard links when adjusting chain
    length.

    You can probably still get lockrings, but I use a track hub, so I've never
    pursued it. You thread on the cog, then the lockring, sealing it in place
    with Loctite. Depending on the wheel, you may have to redish it.

    For a good discussion forum for fixed gear, check out www.bikeforums.net in
    the single speed/fixed gear forum.

    Cheers

    Cam
     
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