Singlespeed & Fixed Gear - Chain tension question

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thirteen
03-18-04, 10:08 AM
Is it normal for the chain tension to be different with two different
pedal positions? This is what is happening...When my right crank is
horizontal my chain is loose, but with the pedals in any other
position the chain is nice and tight. I'm not sure if this is normal
or if is a chainline or chainring issue. My chainline is not perfectly
straight, probably off by a few mm's or a cm. I think my chainring may
be bent slightly, but would this affect chain tension that much? Any
help or resources would be great. I've already checked out park tools
website with little avail.
t

roadfix
03-18-04, 10:14 AM
Your crank/chainring is not completely eccentric. This is very common. Try remounting your chainring.

George
stevo
03-18-04, 10:14 AM
your chainring isnt centered, or you have a biopace ring.

dabern
03-18-04, 10:18 AM
I have an entry level Fuji track that does the same thing. Try recentering your chainring using the mothod here: http://www.sheldonbrown.com/singlespeed.html#tension
Grunk
03-18-04, 10:18 AM
That's normal. Its because your chainring isn't perfectly round or isn't centered exactly on the crank arm. I wouldn't worry about it unless its really loose, then really tight. There's a little article on Sheldon Brown's site that explains how to center you chainring better. Its about half way donw the page under the heading "Chain Tension":

http://www.sheldonbrown.com/fixed.html
Jonny B
03-18-04, 12:26 PM
If your chainline is off by more than 2mm, please FOR THE LOVE OF GOD do something about it. It will come off eventually, and probably quite often, and just at times when you really don't want it to (like pulling away at a busy intersection or slowing down at the bottom of a big hill with a tight bend at the bottom). This is for your own safety. Fixed gears with no chains are like car a truck at the top of a hill with no brakes and no engine: very dangerous and completely useless.