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Main
Date: 08 Mar 2007 12:19:20
From: wightstraker
Subject: A good fixed gear ratio?
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I have a rusty old road bike that I've been fixing up over the year.
I've changed the brakes, replaced the cables, the tires and tubing,
etc.
After all these fixes, however, I still have one major problem with
the bike: the gears. Only 2 of the 12 speeds actually stick, and I
rarely switch between them anyway. I was thinking of dumping the whole
thing and just making it fixed gear bike.
I have two questions for you all: First, how hard would it be to
convert a 12 speed road bike to a fixed gear? I'd do the work myself,
but would the parts be expensive? Second, what would be the best gear
ratio for my bike? I mostly use it to get to around town - nothing too
strenuous; the terrain is relatively flat, but I like to move
quickly.
Thanks for your advice -
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Date: 10 Mar 2007 08:13:09
From: Ravi
Subject: Re: A good fixed gear ratio?
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wightstraker wrote:
> but would the parts be expensive? Second, what would be the best gear
> ratio for my bike? I mostly use it to get to around town - nothing too
> strenuous; the terrain is relatively flat, but I like to move
> quickly.
it is a lot of fun riding a fixie as such. The fun doubles/triples on
hills. mashing you way up the hill and spinning like crazy on the downhill.
big gear:
pro: spin slower on the downhills
con: you need bigger muscles to climb the hill
low gear:
pro: climbing uphill is a bit easier
con: you spin even more on the downhills
the best gear is one that balances your leg strength with leg speed. the
magic number varies from person to person. try different numbers to find
your number. even on flats, a lower gear will develop your spin -
because if you want to get somewhere quick, you would be spinning really
fast or even on your short sprints to get thru the traffic light will be
a spin-a-rama.
I am not sure whether pushing a big gear on flats develop power in your
legs ?
+ravi
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Date: 09 Mar 2007 07:58:47
From: DanKMTB@gmail.com
Subject: Re: A good fixed gear ratio?
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On 9, 10:21 am, "David L. Johnson" <david.john...@lehigh.edu >
wrote:
> Right on the first part, but I presume that it does have horizontal
> dropouts, since it's a 12-speed. That would be a pretty old bike.
>
> On the other hand, you cannot use a chain tensioner with a fixed gear.
> You have to either use an eccentric hub, or be very lucky with the
> choice of gearing so that the chain tension is right. With that you
> also have to worry about chain wear.
Right you are Sir. I somehow mentally transposed my singlespeed,
which has a single speed freewheel, into this instance. Fixed with
vertical dropouts would require lots of luck or extremely careful
gearing choice, and still may not be possible. Singlespeed, on the
other hand, could be accomplished easily enough even with vertical
dropouts through a tensioner (or the old derailer rigged as such).
Hopefully for the OP, you're right and the dropouts are horizontal.
Dan
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Date: 09 Mar 2007 06:01:11
From: DanKMTB@gmail.com
Subject: Re: A good fixed gear ratio?
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On 8, 11:47 pm, "David L. Johnson" <david.john...@lehigh.edu >
wrote:
> wightstraker wrote:
> > I have two questions for you all: First, how hard would it be to
> > convert a 12 speed road bike to a fixed gear?
>
> Trivial.
>
> > I'd do the work myself,
> > but would the parts be expensive?
>
> It can be done on the cheap, for the price of a sprocket ($15) and a
> chain ($10). That requires you to:
>
> 1) remove d=E9railleurs, cable, shifters.
>
> 2) remove chainrings, and put the bigger one where the smaller one was,
> on the inside of the spider. You may want to get shorter chainring
> bolts, or jerry-rig a few washers to space it out.
>
> 3) Remove the freewheel (as it's a 6-speed rear, I presume it's a
> freewheel), and put the sprocket on. It will tighten when you start to
> ride, but be careful not to apply back-pressure on the pedals until you
> have some miles on it, preferably including some hills.
>
> You may have trouble with the chainline. Ideally, the plane of the
> chainring should be the same as that determined by the sprocket. The
> sprocket may be offset by a couple millimeters without trouble, but more
> than that could make it prone to dropping a chain, which is bad. If the
> sprocket is very much too far in (this is likely), you can try
>
> a) putting a spacer in between the sprocket and the hub. Some cassette
> spacers work well, but get a metal one if you can.
>
> b) re-centering the hub on the axle. If you look, there is a big spacer
> on the right side of the axle that pushes the hub to the left, to make
> room for the freewheel. Take that off, and get two about half the size,
> and put one on either side. Sometimes you're lucky and the spacer is
> actually several pieces. Juggle them around until the chainline is
> right. Then, you have to re-dish the wheel to keep the centerline of
> the rim midway between the dropouts.
>
> > Second, what would be the best gear
> > ratio for my bike? I mostly use it to get to around town - nothing too
> > strenuous; the terrain is relatively flat, but I like to move
> > quickly.
>
> Pay attention to the gear you like to use most for this sort of riding
> when on your geared bike. Figure the ratio, and match it as closely as
> you can. Be willing to shell out for extra sprockets, to be able to
> change gears to accommodate your conditioning, road conditions, and
> rides. I have every size from a 12 to a 21. I haven't used the 12, it
> was given to me as a joke. But I have ridden with all the others, for
> one reason or another.
This sounds like a great low budget way to get the project done,
assuming horizontal dropouts. If the bike has vertical dropouts, you
still need a chain tensioner of some sort. I suppose a budget version
could be the existing derailer, with a very short length of cable
fastened to the frame at a given tension.
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Date: 09 Mar 2007 10:21:25
From: David L. Johnson
Subject: Re: A good fixed gear ratio?
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DanKMTB@gmail.com wrote:
>
> This sounds like a great low budget way to get the project done,
> assuming horizontal dropouts. If the bike has vertical dropouts, you
> still need a chain tensioner of some sort. I suppose a budget version
> could be the existing derailer, with a very short length of cable
> fastened to the frame at a given tension.
Right on the first part, but I presume that it does have horizontal
dropouts, since it's a 12-speed. That would be a pretty old bike.
On the other hand, you cannot use a chain tensioner with a fixed gear.
You have to either use an eccentric hub, or be very lucky with the
choice of gearing so that the chain tension is right. With that you
also have to worry about chain wear.
>
--
David L. Johnson
"Business!" cried the Ghost. "Mankind was my business. The common
welfare was my business; charity, mercy, forbearance, and
benevolence, were, all, my business. The dealings of my trade were but
a drop of water in the comprehensive ocean of my business!" --Dickens,
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Date: 09 Mar 2007 05:21:42
From: Qui si parla Campagnolo
Subject: Re: A good fixed gear ratio?
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On 8, 1:19 pm, "wightstraker" <johnaolms...@gmail.com > wrote:
> I have a rusty old road bike that I've been fixing up over the year.
> I've changed the brakes, replaced the cables, the tires and tubing,
> etc.
>
> After all these fixes, however, I still have one major problem with
> the bike: the gears. Only 2 of the 12 speeds actually stick, and I
> rarely switch between them anyway. I was thinking of dumping the whole
> thing and just making it fixed gear bike.
>
> I have two questions for you all: First, how hard would it be to
> convert a 12 speed road bike to a fixed gear? I'd do the work myself,
> but would the parts be expensive? Second, what would be the best gear
> ratio for my bike? I mostly use it to get to around town - nothing too
> strenuous; the terrain is relatively flat, but I like to move
> quickly.
>
> Thanks for your advice -
If it's a freewheel type rear wheel with a horizontal dropout type
frame, all you need is a cog, a chain and short chaintring bolts,
about $30. Use the inner ring only(take the big one off), take the
freewheel off, add the cog, size the chain, take off the derailleurs
and go ride. I use a 42-16 for all around city type riding.
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Date: 08 Mar 2007 21:04:45
From: wightstraker
Subject: Re: A good fixed gear ratio?
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Thanks to all of you for your thoughtful, detailed advice. I'm much
more confident about "making the switch" now.
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Date: 08 Mar 2007 23:47:12
From: David L. Johnson
Subject: Re: A good fixed gear ratio?
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wightstraker wrote:
> I have two questions for you all: First, how hard would it be to
> convert a 12 speed road bike to a fixed gear?
Trivial.
> I'd do the work myself,
> but would the parts be expensive?
It can be done on the cheap, for the price of a sprocket ($15) and a
chain ($10). That requires you to:
1) remove dérailleurs, cable, shifters.
2) remove chainrings, and put the bigger one where the smaller one was,
on the inside of the spider. You may want to get shorter chainring
bolts, or jerry-rig a few washers to space it out.
3) Remove the freewheel (as it's a 6-speed rear, I presume it's a
freewheel), and put the sprocket on. It will tighten when you start to
ride, but be careful not to apply back-pressure on the pedals until you
have some miles on it, preferably including some hills.
You may have trouble with the chainline. Ideally, the plane of the
chainring should be the same as that determined by the sprocket. The
sprocket may be offset by a couple millimeters without trouble, but more
than that could make it prone to dropping a chain, which is bad. If the
sprocket is very much too far in (this is likely), you can try
a) putting a spacer in between the sprocket and the hub. Some cassette
spacers work well, but get a metal one if you can.
b) re-centering the hub on the axle. If you look, there is a big spacer
on the right side of the axle that pushes the hub to the left, to make
room for the freewheel. Take that off, and get two about half the size,
and put one on either side. Sometimes you're lucky and the spacer is
actually several pieces. Juggle them around until the chainline is
right. Then, you have to re-dish the wheel to keep the centerline of
the rim midway between the dropouts.
> Second, what would be the best gear
> ratio for my bike? I mostly use it to get to around town - nothing too
> strenuous; the terrain is relatively flat, but I like to move
> quickly.
Pay attention to the gear you like to use most for this sort of riding
when on your geared bike. Figure the ratio, and match it as closely as
you can. Be willing to shell out for extra sprockets, to be able to
change gears to accommodate your conditioning, road conditions, and
rides. I have every size from a 12 to a 21. I haven't used the 12, it
was given to me as a joke. But I have ridden with all the others, for
one reason or another.
--
David L. Johnson
"Business!" cried the Ghost. "Mankind was my business. The common
welfare was my business; charity, mercy, forbearance, and
benevolence, were, all, my business. The dealings of my trade were but
a drop of water in the comprehensive ocean of my business!" --Dickens,
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Date: 09 Mar 2007 17:50:35
From: John Thompson
Subject: Re: A good fixed gear ratio?
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On 2007-03-09, David L. Johnson <david.johnson@lehigh.edu > wrote:
> wightstraker wrote:
>
>> I have two questions for you all: First, how hard would it be to
>> convert a 12 speed road bike to a fixed gear?
>
> Trivial.
>
>> I'd do the work myself,
>> but would the parts be expensive?
>
> It can be done on the cheap, for the price of a sprocket ($15) and a
> chain ($10). That requires you to:
>
> 1) remove dérailleurs, cable, shifters.
>
> 2) remove chainrings, and put the bigger one where the smaller one was,
> on the inside of the spider.
Unless you're a real gear-masher, you may want to leave the inner ring
where it is and just remove the outer ring.
> You may want to get shorter chainring bolts, or jerry-rig a few
> washers to space it out.
BMX single chainring bolts are cheap, effective and widely available.
> 3) Remove the freewheel (as it's a 6-speed rear, I presume it's a
> freewheel), and put the sprocket on. It will tighten when you start to
> ride, but be careful not to apply back-pressure on the pedals until you
> have some miles on it, preferably including some hills.
For added security, put a bottom bracket lockring on to help hold the
cog in place. Another option would be to use a single cog BMX freewheel
intead of a fixed cog. You can pick one up at the same place you get the
chainring bolts... :-)
> You may have trouble with the chainline. Ideally, the plane of the
> chainring should be the same as that determined by the sprocket. The
> sprocket may be offset by a couple millimeters without trouble, but more
> than that could make it prone to dropping a chain, which is bad. If the
> sprocket is very much too far in (this is likely), you can try
>
> a) putting a spacer in between the sprocket and the hub. Some cassette
> spacers work well, but get a metal one if you can.
Sturmey-Archer cog spacers are just the ticket for this job. They can
also be used under the bottom bracket fixed cup if you need to move the
ring out a little.
As long as your chainring and cog are designed for 3/32" width chain,
you can just shorten your current chain to make it work with the new
setup.
--
John (john@os2.dhs.org)
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Date: 08 Mar 2007 14:12:10
From: landotter
Subject: Re: A good fixed gear ratio?
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On 8, 3:39 pm, "wightstraker" <johnaolms...@gmail.com > wrote:
> On 8, 3:29 pm, catzz66 <dingd...@rammalamma.net> wrote:
>
>
>
> > wightstraker wrote:
> > > I have a rusty old road bike that I've been fixing up over the year.
> > > I've changed the brakes, replaced the cables, the tires and tubing,
> > > etc.
>
> > > After all these fixes, however, I still have one major problem with
> > > the bike: the gears. Only 2 of the 12 speeds actually stick, and I
> > > rarely switch between them anyway. I was thinking of dumping the whole
> > > thing and just making it fixed gear bike.
>
> > > I have two questions for you all: First, how hard would it be to
> > > convert a 12 speed road bike to a fixed gear? I'd do the work myself,
> > > but would the parts be expensive? Second, what would be the best gear
> > > ratio for my bike? I mostly use it to get to around town - nothing too
> > > strenuous; the terrain is relatively flat, but I like to move
> > > quickly.
>
> > > Thanks for your advice -
>
> > Besides the coolness factor of converting to a fixed gear, a reasonable
> > alternative might be to continue riding it the way you are doing now.
> > Find a gear ratio that works for you and stick with it. Not trying to
> > be flip with this answer, but that would accomplish your purpose.
>
> Good point. That's essentially how I've been riding now. I just feel a
> little silly riding around with a bunch of gears I don't need. I also
> have some practical issues too: Extra gears add weight, and require a
> lot more maintenance. Nobody likes a popped chain...
First read this:
http://www.sheldonbrown.com/fixed-conversion.html
If you have vertical dropouts, it's possible, but can be a real PITA
to go fixed, but singlespeed with a tensioner is always an option.
If you have a screw on freewheel, remove it and thread on a track cog
with some locking compound. Use an old bottom bracket lock ring to
snug it up if you have enough threads. Don't "engine brake" till
you've climbed a nice big hill to torque it on. Leave both brakes
installed. You'll need to move the axle and redish the wheel to get
the chainline right.
If it's a 6speed cassette hub, then you have a number of options:
Replace the freehub body with a Surly Fixxer, no redishing necessary.
A bit expensive
Use spacers (or PVC pipe), and a Shimano DX ($5) and make a cool
single speed.
Rebuild wheel on a fixed gear hub.
Gear ratio: if you use your 42t ring up front then 16t in the rear is
great for rolling terrain. 15t is good for flats or if you're a strong
climber, 17t if it's pretty hilly and you don't want to get all veiny.
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Date: 08 Mar 2007 13:39:31
From: wightstraker
Subject: Re: A good fixed gear ratio?
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On 8, 3:29 pm, catzz66 <dingd...@rammalamma.net > wrote:
> wightstraker wrote:
> > I have a rusty old road bike that I've been fixing up over the year.
> > I've changed the brakes, replaced the cables, the tires and tubing,
> > etc.
>
> > After all these fixes, however, I still have one major problem with
> > the bike: the gears. Only 2 of the 12 speeds actually stick, and I
> > rarely switch between them anyway. I was thinking of dumping the whole
> > thing and just making it fixed gear bike.
>
> > I have two questions for you all: First, how hard would it be to
> > convert a 12 speed road bike to a fixed gear? I'd do the work myself,
> > but would the parts be expensive? Second, what would be the best gear
> > ratio for my bike? I mostly use it to get to around town - nothing too
> > strenuous; the terrain is relatively flat, but I like to move
> > quickly.
>
> > Thanks for your advice -
>
> Besides the coolness factor of converting to a fixed gear, a reasonable
> alternative might be to continue riding it the way you are doing now.
> Find a gear ratio that works for you and stick with it. Not trying to
> be flip with this answer, but that would accomplish your purpose.
Good point. That's essentially how I've been riding now. I just feel a
little silly riding around with a bunch of gears I don't need. I also
have some practical issues too: Extra gears add weight, and require a
lot more maintenance. Nobody likes a popped chain...
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Date: 08 Mar 2007 17:09:00
From: catzz66
Subject: Re: A good fixed gear ratio?
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wightstraker wrote:
>
>>Besides the coolness factor of converting to a fixed gear, a reasonable
>>alternative might be to continue riding it the way you are doing now.
>>Find a gear ratio that works for you and stick with it. Not trying to
>>be flip with this answer, but that would accomplish your purpose.
>
>
> Good point. That's essentially how I've been riding now. I just feel a
> little silly riding around with a bunch of gears I don't need. I also
> have some practical issues too: Extra gears add weight, and require a
> lot more maintenance. Nobody likes a popped chain...
>
That was just what someone advised me. I continued riding the old Fuji
I had bought until I was ready to go to something more modern.
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Date: 08 Mar 2007 22:12:00
From: nash
Subject: Re: A good fixed gear ratio?
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"wightstraker" <johnaolmsted@gmail.com > wrote in message
news:1173389971.610668.175760@n33g2000cwc.googlegroups.com...
> On 8, 3:29 pm, catzz66 <dingd...@rammalamma.net> wrote:
>> wightstraker wrote:
>> > I have a rusty old road bike that I've been fixing up over the year.
>> > I've changed the brakes, replaced the cables, the tires and tubing,
>> > etc.
>>
>> > After all these fixes, however, I still have one major problem with
>> > the bike: the gears. Only 2 of the 12 speeds actually stick, and I
>> > rarely switch between them anyway. I was thinking of dumping the whole
>> > thing and just making it fixed gear bike.
>>
>> > I have two questions for you all: First, how hard would it be to
>> > convert a 12 speed road bike to a fixed gear? I'd do the work myself,
>> > but would the parts be expensive? Second, what would be the best gear
>> > ratio for my bike? I mostly use it to get to around town - nothing too
>> > strenuous; the terrain is relatively flat, but I like to move
>> > quickly.
>>
>> > Thanks for your advice -
>>
>> Besides the coolness factor of converting to a fixed gear, a reasonable
>> alternative might be to continue riding it the way you are doing now.
>> Find a gear ratio that works for you and stick with it. Not trying to
>> be flip with this answer, but that would accomplish your purpose.
>
> Good point. That's essentially how I've been riding now. I just feel a
> little silly riding around with a bunch of gears I don't need. I also
> have some practical issues too: Extra gears add weight, and require a
> lot more maintenance. Nobody likes a popped chain...
And I guess you looked at the derailleur cable being tight enough to keep it
changed.
What are you doing to pop a chain.
I really do not maintain my free wheel much except to power wash it once in
a blue moon. Maintaining an clean chain is harder for me and you cannot do
with out those yet.
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Date: 08 Mar 2007 15:29:12
From: catzz66
Subject: Re: A good fixed gear ratio?
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wightstraker wrote:
> I have a rusty old road bike that I've been fixing up over the year.
> I've changed the brakes, replaced the cables, the tires and tubing,
> etc.
>
> After all these fixes, however, I still have one major problem with
> the bike: the gears. Only 2 of the 12 speeds actually stick, and I
> rarely switch between them anyway. I was thinking of dumping the whole
> thing and just making it fixed gear bike.
>
> I have two questions for you all: First, how hard would it be to
> convert a 12 speed road bike to a fixed gear? I'd do the work myself,
> but would the parts be expensive? Second, what would be the best gear
> ratio for my bike? I mostly use it to get to around town - nothing too
> strenuous; the terrain is relatively flat, but I like to move
> quickly.
>
> Thanks for your advice -
>
Besides the coolness factor of converting to a fixed gear, a reasonable
alternative might be to continue riding it the way you are doing now.
Find a gear ratio that works for you and stick with it. Not trying to
be flip with this answer, but that would accomplish your purpose.
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