Fixed gear conversion questions

[Bruni]

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 > wrote in message
...
>
> 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

[Michael Press]

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

[Sheldon Brown]

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
+----------------------------------------------------------------+
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| 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

[Werehatrack]

On Fri, 07 May 2004 09:26:25 -0400, Michael Press
> 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.

[toolguy]

>>
>> 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

[Sheldon Brown]

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

[Michael Press]

Sheldon Brown > 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

[toolguy]

On Fri, 07 May 2004 11:34:29 -0400, Sheldon Brown
> 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)

[Erik Brooks]

Sheldon Brown > wrote in message >...
>
> 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

[Sheldon Brown]

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

[Jeff Wills]

Werehatrack > wrote in message >...
> On Fri, 07 May 2004 09:26:25 -0400, Michael Press
> > 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

[David L. Johnson]

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

[Elmo Spam King]

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

[A Muzi]

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

[A Muzi]

>>>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

[Werehatrack]

On Fri, 07 May 2004 17:50:37 -0700, Elmo Spam King
> 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.

[Qui si parla Campagnolo]

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"

[[email protected]]

On 2004-05-08, Qui si parla Campagnolo > 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

[Michael Press]

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

[[email protected]]

On 2004-05-10, Michael Press > wrote:
> 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

[David L. Johnson]

On Sun, 09 May 2004 21:01:33 -0400, Michael Press wrote:

> 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.

If there is room to move the wheel forward or backward about 1/2", that
will do nicely. Forget, though, the tensioner. If you only have 1/4" of
forward/rearward motion, you can still make it work. You may not need
this if the numbers work out in your favor, but you can get extra
flexibility by getting a half-link. These are only available for 1/8"
chain, which you can use.

>
> Can you give more detail on this - what's a bottom bracket lockring? Is
> that from an old-style bottom bracket?

Yes. The old, non-cartridge bottom brackets use a separate lockring on
the left side to secure the left cup. On English thread bottom brackets,
that lockring will fit on the hub threads of an old freewheel-style hub.
I do suggest that a real track hub is better, but....

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?

Should be available, but not easy to find. Easier to find an old bike --
cheaper to buy the bike for the lockring than to order it special. Seems
a waste, but you can put a cartridge bottom bracket on the old bike,
maybe.

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

If you are not using a track hub, which has left-hand threads for the
lockring, some sort of goop to hold the lockring and sprocket in place is
a good idea.

--

David L. Johnson

__o | What is objectionable, and what is dangerous about extremists is
_`\(,_ | not that they are extreme, but that they are intolerant. --Robert
(_)/ (_) | F. Kennedy

[Ed Cory]

Michael Press > wrote in message >...
> 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.
>
<SNIP>

If you really mean "as cheaply as possible" then you can
1. disassemble the freewheel & degrease the innards
2. reassemble it using JB Weld or similar structural
epoxy instead of lubricant (put the bearings into the
epoxy so that it aligns... experience talking)
3. shuffle cogs, if desired, to improve chainline
4. degrease & threadlock the freewheel onto the hub
5. possibly swap inner and outer chainrings to give more
gear ratios with a smaller chain length variation

Forget that "buying" and redishing for a while.
Maybe buy (Ouch!) SRAM powerlink(s) to trivialize chain
length/gear ratio changes.

Using 39 and 42t rings can give several ratios with no
chain length changes (depends on your dropouts). I've been
happy riding fixed on my 53t ring with only horiz dropouts
supporting changing between two "fixed" gears. I change
gears on the road in about a minute.

I'm suspicious that the use of the larger gears reduces
the tendency to dechain in addition to the increased chain
and gear life you get for free. I did not disturb my
freewheel cogs to optimize chainline nor did I spend on
a new retro-chain.

(on topic) Ed