Bicycle Mechanics - A Chain Question for you: Help!

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BigHit-Maniac
07-30-04, 08:02 AM
Hey guys... what's up?

A quick question. I have a 2004 Demo 9, and it makes a "popping" noise when I pedal. On occasion, sort of like an out-of-round sprocket does on a brand-new BMX bike. My bike is about a month old, and it's still making the popping noise. I can feel it in the pedals when it does it, yet my BB, rear hub, and drivetrain are rock-solid and tight. Could it be my stupid stock chain?

I remember my 2003 BigHit did the same darned thing.. but I forget how I got rid of the issue.

Should I swap my chain out for a new Sram PC-69? I had awesome luck with Sram chains on my BigHit, and hate the stock Shimano POS chain thats on my bike now.

WHats you guy's opinion(s)?


Thanks!!

-Matt

BiKe_GuY666
07-30-04, 01:42 PM
Have you checked the chain for any broken links? If there arent any I would swap the chain to be on the safe side.
BigHit-Maniac
07-30-04, 11:49 PM
Yeah, I just replaced the chain with a brand new Sram PC-69. It still does it. :(

Any other ideas? No stiff links, everything's tight, and the derailleur is properly adjusted.

-Matt

BiKe_GuY666
08-01-04, 11:55 AM
Have you checked the pedals or the crank for any problems. I doubt thats it, but you can check. You never know.
khuon
08-01-04, 01:58 PM
Have you checked to make sure your rear wheel is properly seated in the dropouts? I know it sounds like a stupid question...
MudPie
08-01-04, 02:30 PM
Yeah, I just replaced the chain with a brand new Sram PC-69. It still does it. :(

Any other ideas? No stiff links, everything's tight, and the derailleur is properly adjusted.

-Matt

Rats... I was pretty sure the chain would be the culprit. I'm not a big fan of Shimano chains and prefer the SRAM.

Have you inspected the teeth on the cogs and chainring? Perphaps one is bent, deformed or missing.

Does the popping occur all the time or only when you're exerting force?
Pittard
08-01-04, 04:10 PM
it's a brand new chain so it can't be wear so maybe it's wear on your chainringyour links are the wrong size or something? Try pulling on the chain at the front of your chainring see if a bit of a chain tooth or all of a chain tooth is revealed! if it is something is not right could be the chain or the chainring. This is just a suggestion so if it's incorrect i can only apologise!
supcom
08-01-04, 04:41 PM
If the noise is in sync with your pedalling, then look for a loose crank arm or pedal. It could also be the seat since noises are often hard to locate.

If the noise happens at random crank positions, then look at the chain and rear. I had a brand new SRAM chain on a brand new bike that was missing one roller. You had to look close to see it. At random points, the cranks would kind of jump just a hair.
Dannihilator
08-01-04, 08:43 PM
Have you checked to make sure your rear wheel is properly seated in the dropouts? I know it sounds like a stupid question...

The demo9 has a thru axel rear so it was more than likely in the dropouts.