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Discussion Starter · #1 ·
Question for the forum......

How do you adjust the chain on your fixie?? What position should your pedals be for proper adjustment?? I know its loose in some positions and tight at others, is there a secret formula??

Thanks in advance,
Mack :cool:
 

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Don't own a fixie yet, but I've got a lot ov BMX experience... hopefully it applies here. If not, disregard! :p

When I raced we'd put our bikes in the stand and spin the wheel to see when the chain tightened up. Because chainrings aren't perfect circles, it'll be tighter in one position than it is anywhere else. Anyhow, when it got to the tightest point, we'd stop it there and adjust the back wheel accordingly. I found the easiest way to do this and keep everything square was to loosen the bolts on the axles and adjust the tire with the chain tensioner, pulling out till there was enough slack to let the cranks spin smoothly, but not so much slack that the chain is hopping around. If you don't have a tensioner, you can just pull back on the drive side axle till you get it to the proper tension. When you get it all tensioned up be sure to give her a few spins to make sure that the chain is not tightening up too much that it actually slows down.

Hope I helped. And if things work differently for a fixie, lemme know!



joe
 

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When in doubt, ask Sheldon Brown

Personally, I think this is more complicated than it needs to be, but the following excerpt from Sheldon Brown's excellent web page is thorough, if nothing else:

"The chain tension on a fixed gear is quite critical, and is regulated by moving the rear axle back and forth in the fork ends. If the chain is too tight, the drive train will bind, perhaps only at one angle of the pedals (chainwheels are not usually perfectly concentric). It should be tight as it can be without binding. If the chain is too loose, it can fall off, which is quite dangerous on a fixed gear.

Set the rear axle so that the chain pulls taut at the tightest part of the cranks' rotation. One at a time, loosen up each of the stack bolts, and tighten it back just finger tight. Spin the crank slowly and watch for the chain to get to its tightest point. Strike the taut chain lightly with a convenient tool to make the chain ring move a bit on its spider. Then rotate the crank some more, finding the new tightest spot, and repeat as necessary.

This takes a little bit of your hands learning how hard to hit the chain, and how loose to set the stack bolts, but it is really quite easy to learn.

Tighten up the stack bolts a bit and re-check. Tighten the stack bolts in a regular pattern, like the lug nuts on a car wheel. My standard pattern is to start by tightening the bolt opposite the crank, then move clockwise 2 bolts (144 degrees), tighten that one, clockwise 2 more, and so on. Never tighten two neighboring bolts in a row. You may prefer to go counterclockwise, but try to get in the habit of always starting at the same place and always going the same way. This reduces the chances of accidentally missing a bolt.

Once you have the chainrings centered and secured, adjust the position of the rear axle to make the chain as nearly tight as possible without binding. Notice how freely the drive train turns when the chain is too loose. That is how freely it should turn when you are done, but with as little chain droop as possible."

For more, go to http://www.sheldonbrown.com/fixed.html
 

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Discussion Starter · #5 ·
Thanks Joe......will try tonight. But it sounds like the right way to adjust. will let you folks know how it goes....

Mack :D

JoeDaddio said:
Don't own a fixie yet, but I've got a lot ov BMX experience... hopefully it applies here. If not, disregard! :p

When I raced we'd put our bikes in the stand and spin the wheel to see when the chain tightened up. Because chainrings aren't perfect circles, it'll be tighter in one position than it is anywhere else. Anyhow, when it got to the tightest point, we'd stop it there and adjust the back wheel accordingly. I found the easiest way to do this and keep everything square was to loosen the bolts on the axles and adjust the tire with the chain tensioner, pulling out till there was enough slack to let the cranks spin smoothly, but not so much slack that the chain is hopping around. If you don't have a tensioner, you can just pull back on the drive side axle till you get it to the proper tension. When you get it all tensioned up be sure to give her a few spins to make sure that the chain is not tightening up too much that it actually slows down.

Hope I helped. And if things work differently for a fixie, lemme know!



joe
 

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Joe nailed it but just to add, you'll eventually figure out what is too loose or too tight. I try to aim for 1/2" of vertical play in the chain.
 

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another quick tip...

If you are in a hurry, you can check if the chain has too much slack by holding the bike on its side and spinning the cranks. Let the drivetrain spin on it's own for a few revolutions and, if your up to it, tap the outside of your moving chain with your hand..... Be very careful if you choose to do this, if you are not careful you may lose your finger. If the chain does not fall off, you are set, go ahead and torque up the bolts to prevent slippage.
 

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What I do.

I put the bike in a stand at set the cranks so the chain is at its tightest point. I then loosen both track nuts, pull both sides back so the wheel stays centered between the seat stays, and simultaneously hand tighten both sides. Next I use a ratcheting box wrench to sock down the track nuts. I alternate sides, tightening 1/2 turn at a time and use the wrench so that every tightening motion is pulling toward the back of the back. My guide for chain tension is 1/2 inch of up and down movement.
 

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rusa1586 said:
I put the bike in a stand at set the cranks so the chain is at its tightest point. I then loosen both track nuts, pull both sides back so the wheel stays centered between the seat stays, and simultaneously hand tighten both sides. Next I use a ratcheting box wrench to sock down the track nuts. I alternate sides, tightening 1/2 turn at a time and use the wrench so that every tightening motion is pulling toward the back of the back. My guide for chain tension is 1/2 inch of up and down movement.
I do pretty much the same thing, but I also use a partially used roll of electrical tape in between the back wheel and frame. The roll is squished into a deformed C shape and I just rotate the wheel to apply pressure on the tape roll. I find having that roll as a wedge makes keeping the tire centered very easy. Kinda acts as a third hand to hold the wheel in place.
 

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Pull wheel back to snug chain, leave wheel off centered biased to the left. Tighten left nut partway. Pull wheel to desired chain taughtness, tighten right nut which should pull wheel close to center. Check chain tension and wheel alignment. Fully tighten nuts.
 

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Discussion Starter · #11 ·
Guys,,,,,

I tried the loosening of the chain ring bolts for adjusting the crank rotation, but I don't think it worked out to well. I still have that really tight spot in the chain rotation and then it gets loose again. Maybe about 1/2" - 1" ot play when I hit the loose spots, do I need to worry about this? or keep trying with the chain ring bolt adjustment. First time I've tried this and its a bit different...........

Thanks,
Mack :rolleyes:
 

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CioccLA said:
Guys,,,,,

I tried the loosening of the chain ring bolts for adjusting the crank rotation, but I don't think it worked out to well. I still have that really tight spot in the chain rotation and then it gets loose again. Maybe about 1/2" - 1" ot play when I hit the loose spots, do I need to worry about this? or keep trying with the chain ring bolt adjustment. First time I've tried this and its a bit different...........

Thanks,
Mack :rolleyes:

I found that the chainring bolt adjustments that Sheldon Brown advocates had little effect, or I lacked the patience/skill to do it right. Tighten them up and try one of the other suggestions for getting the chain tension right. An inch of play is excessive.
 

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Discussion Starter · #13 ·
:mad: I thought it was just my technique or lack of technique, because I did not see that much of an improvement. I will try the ol' roll of tape move suggested by "Magic" in a previous post............Thanks fixintogo , I see I'm not alone in this!!!!

Thanks folks,
Mack :cool:

fixintogo said:
I found that the chainring bolt adjustments that Sheldon Brown advocates had little effect, or I lacked the patience/skill to do it right. Tighten them up and try one of the other suggestions for getting the chain tension right. An inch of play is excessive.
 

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CioccLA said:
:mad: I thought it was just my technique or lack of technique, because I did not see that much of an improvement. I will try the ol' roll of tape move suggested by "Magic" in a previous post............Thanks fixintogo , I see I'm not alone in this!!!!

Some cranks are just too far out of wack to get right. If you've given it your best shot, give up an except a slightly tight spot and a slightly loose spot. If tight spot does not bind and the loose spot does not drop the chain you'll be fine.
 

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1/2 inch is certainly fine. 1" depends on your pickiness.

I doubt 1" would allow the chain to fall off, but I like the feel of a tight chain with almost no slack feeling when I start pedalling.
 

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FWIW, a few months ago I bit the bullet and bought a new chainring, chain, and cog, and my drivetrain immediately operated smoother, quieter, and with fewer adjustment woes. I'm guessing that fixies stretch chains and wallow out the teeth of cogs and rings pretty fast, given the demands placed on these components. Perhaps some of the tight/loose issues discussed herein might be resolved by a new chain.
 

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I've only had 2 rides on my fixed gear, and am running into tension issues as well. The first ride I had pulled the chain way tight, and there was little play in the chain, but if you spun the wheel it quickly stopped (chain was binding coming off the chainring teeth). After reading this thread, I loosened it a bit, and now it spins freely, and the chain doesn't seem anywhere near falling off, but as the cranks change direction there is noticable slack before the chain tightens on the top or bottom before engaging. This is very annoying, but the drivetrain is much smoother while continuously pedaling.

I'm thinking it's just a worn out chain, and a new one would tighten it up (and probably save my cog some life at the same time). Does that sound right, or did I just loosen too far?
 

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imetis said:
I've only had 2 rides on my fixed gear, and am running into tension issues as well. The first ride I had pulled the chain way tight, and there was little play in the chain, but if you spun the wheel it quickly stopped (chain was binding coming off the chainring teeth). After reading this thread, I loosened it a bit, and now it spins freely, and the chain doesn't seem anywhere near falling off, but as the cranks change direction there is noticable slack before the chain tightens on the top or bottom before engaging.
imetis: I think we have a conflict of terminology.

Typically, "binding" is when a chain is stretched so tight it stops the chainwheel and cog from spinning. Please clarify what you mean by "chain was binding coming off the chainring teeth."

Also, please explain what you mean by "the cranks change direction" and "noticable slack before the chain tightens on the top or bottom before engaging."

I'm trying to visualize what's happening here and why it's annoying. Thanks!
 

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Sorry for the confusion. Yes, the chain was stopping the chainwheel and cog from spinning. Looking closely, I could see and hear it catching on the teeth of the chainring, specificly the last tooth on the chainring before making it's way to the cog. It was not so tight that it wouldn't move at all, but it did slow things down significantly.

Regarding the slack, it was noticable when track standing, when making that minor motion from forward pressure to backward pressure. Also, in the instant when begining to slow down. Forward pedalling kept the chain tight, but if I let off, and the wheel/cog rotated faster than the crank, there was a bit of slop while the chain tightened in the other direction. As I try to turn the crank by hand, I can see the chain stretching and compressing. When pedaling forward the section of chain above the cog and chainring is tight, and there is slack in the section below. When back pedaling the opposite is true.

Make sense?

fixintogo said:
imetis: I think we have a conflict of terminology.

Typically, "binding" is when a chain is stretched so tight it stops the chainwheel and cog from spinning. Please clarify what you mean by "chain was binding coming off the chainring teeth."

Also, please explain what you mean by "the cranks change direction" and "noticable slack before the chain tightens on the top or bottom before engaging."

I'm trying to visualize what's happening here and why it's annoying. Thanks!
 

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imetis said:
Sorry for the confusion. Yes, the chain was stopping the chainwheel and cog from spinning. Looking closely, I could see and hear it catching on the teeth of the chainring, specificly the last tooth on the chainring before making it's way to the cog. It was not so tight that it wouldn't move at all, but it did slow things down significantly.

Regarding the slack, it was noticable when track standing, when making that minor motion from forward pressure to backward pressure. Also, in the instant when begining to slow down. Forward pedalling kept the chain tight, but if I let off, and the wheel/cog rotated faster than the crank, there was a bit of slop while the chain tightened in the other direction. As I try to turn the crank by hand, I can see the chain stretching and compressing. When pedaling forward the section of chain above the cog and chainring is tight, and there is slack in the section below. When back pedaling the opposite is true.

Make sense?

Totally -- thank you! I know exactly what you mean, as I've experienced the same thing. Unfotunately, I don't know of a quick fix except to say that when I made the aforementioned chain replacement, the problem was minimized if not eliminated. Wait for others to weigh in on this, though, as ther may be a cheaper solution.
 
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