Chain Trouble

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01-15-02 | 05:25 AM

alan

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From: Australia

Chain Trouble

When the left pedal is up and the right pedal is down the chain is really tight but when the left pedal is down the cahin is loose. What's wrong?

It is a B.M.X bike.

01-15-02 | 05:42 AM

Campag Fetish Boy

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From: Madrid and Alicante

Bikes: Orbea Orca OMR

The most likely cause is that you have a "not quite round" chainring or freewheel.

See diagram attached On the second drawing I forgot to say that chain tension would be at it's highest in this configuration.

Last edited by Campag Fetish Boy; 01-15-02 at 10:26 AM.

01-15-02 | 09:28 AM

RainmanP

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From: New Orleans, LA

Do you by any chance have Shimano Bio Pace chainrings? They are kind of rounded square in shape and there for act like out of round rings, because they are. They would probably have yellow logo on the side saying "Bio Pace".

If your rear wheel is installed out of line this could happen, but you would probably notice.

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01-15-02 | 04:13 PM

D*Alex

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From: upstate New York

I'll bet your spindle is bent.

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01-15-02 | 05:41 PM

alan

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From: Australia

Do you mean spindle or sprocket?

01-15-02 | 05:43 PM

Dirtgrinder

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From: Jefferson City, MO

I'm thinking he means the BB spindle.

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01-15-02 | 09:37 PM

alan

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From: Australia

I posted this on another forum and they said it was the sprocket I stuffed up.

01-15-02 | 11:25 PM

pat5319

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From: Spokane WA

Bikes: Seven Axiom Ti, Trek 620, Masi cylocross (steel). Masi Souleville 8spd, Fat Chance Mtn. (steel), Schwinn Triple Bar cruiser, Mazi Speciale Fix/single, Schwinn Typhoon

Don't worry about tension difference, it happens on ( almost) ALL one speeds with one piece cranks, be they BMX, Cruisers etc. If I ever run across one with perfect tension during the entire circle I'll be very surprised.

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Pat

Last edited by pat5319; 01-15-02 at 11:28 PM.

01-16-02 | 02:53 AM

alan

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From: Australia

There are 3-peice cranks.

01-16-02 | 07:13 AM

#10

john999

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If you have the chain adjustment bolts at different lengths it will cause this problem.

01-16-02 | 05:23 PM

#11

alan

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From: Australia

I think I have got the chain right now. I ended up only tightening one tensioner, but I can hear a creak. I can't tell if it is from the freewheel or sprocket.