Fixed gear conversion questions

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

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 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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Phone 617-244-9772 FAX 617-244-1041
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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.

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

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

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

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)

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

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
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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