[BigHit-Maniac]

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

 

[dukeblaster]

i had a simiular thing happen on a rockhopper that i was converting into a single speed. For me it was happening when i torqued really hard and the chain would make a loud snap or pop noise. I found this was the chain actually sliding over the gears. If its a sudden pop and a jolt of your pedals then i bet that is what is happening. This usually happens on older bikes when the gears become rounded out and they don't hold as well, but since your bike is so new I can't imagine this to be the case.

The adjustment that could fix this is a little screw that is on your rear derailleur. this little screw is towards the bottom of the bike usually and the end of the screw hits a little block of metal on the frame usually. If you unscrew the screw (ie turn counter clockwise) this will angle your entire derailluer counterclockwise which will wrap more chain around the gear making it harder to skip it. now it might not look like it angled alot but just a slight adjustment can do alot. Also be careful not to angle it too far or those small gears on your derailluer will touch the gears on your rear cassette which isn't a very good thing. I have found this adjustment to be easy and sometimes it does the trick. you also might havta monkey with some other settings to get your bike to shift right but usually not.

 

[BigHit-Maniac]

Awesome.

Thanks for the reply. I'll give those suggestions a try this afternoon.

I figured I'd go ahead and throw a PC-59 on there anyway.




-Matt

 

[BigHit-Maniac]

Damnit! It still does it, even after I threw on a brand new PC-59 chain, and adjusted the B-Tension screw.

Anyone have any ideas?



-Matt

 

[bear]

Dirty / loose pivots?

While not the first thing I would check, it is a possible cause.

Sounds crazy but it happens on some of these complex bikes.

You get dirt worked into a pivot, or slop, and you can get noises like that.

If it's dirt, you won't be able to notice any slop with the bike "on the stand" just when putting the system under load.

It's remotely possible that you've got worn bearings too, which could cause it.

 

[BigHit-Maniac]

Hmmmm...

I'll do a tear-down sometime here pretty soon, and check the rear pivots.

Thanks for the ideas..