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Campy drivetrain grinding noise/sensation [help?](4 posts)

Campy drivetrain grinding noise/sensation [help?]Velocipedio
Sep 2, 2002 4:35 PM
Very strange problem...

I just had my Campy 10sp chain changed after about 5500 km. There was minimal stretch, but the sideplates were getting a bit sloppy. Since this was the third chain on the cassette, I also changed the cassette. There was some wear in the smaller cogs and a fair bit in the 16t, but I did it mostly as a preventative measure.

Now, I notice a very slight griding noise, or rather more of a sensation in my pedal stroke [on either side] between about one o'clock and three o'clock, but only in the small chainring. The noise/sensation is ONLY apparent at low speeds and low cadence, and when I'm climbing. I don't notice it at all when I'm spinning, or even down around 60 rpm.

What i'm wondering is whether I need a new chainring. It ONLY happens in the small chainring [so I know it's not the cogs or the chain], but I can't see any wear in the chainring teeth -- no shark's teeth. Is this just a breaking-in thing, or should I really get a new small chainring [gahhhhhhhhh! another expense!] before I damage the chain and the cogs? Will I wear the chainring back into smoothness?

Before you ask, yes, I've checked my chainline, and there's no FD rubbing...

Help would be appreciated.
Mea culpa -- gray8110 is having the same problem... [nm]Velocipedio
Sep 2, 2002 4:41 PM
re: Campy drivetrain grinding noise/sensation [help?]gray8110
Sep 3, 2002 12:39 AM
Yeah, take a look at the rear derailleur and hanger. Whatever is bent on my bike.. whether it is the hanger or the derailleur.. it is bent in such a way that the chain leaves the derailleur at a clean angle when going to the big chainring, but hits the side of the jockey when I'm in the small chainring. If the chainring is worn, you'd know it.. Lemme know what you find. What you describe is EXACTLY what is happening to me. It's a soft noise that you can feel and hear and it only happens in the small ring when you are putting some power into the machine. When I initially felt it I thought it was the BB because it felt close to the pedals. I'm bringing my bike in tommorow.. hopefully I'll get it back tommorow and I'll know the result myself.

Spence
Well...Velocipedio
Sep 4, 2002 5:34 AM
The derailleur is as straight as an arrow and the chain seems to be the right length. I'm leaning towards one of two possibilities:

1. The small chainring is slightly worn. A wrench I respect says you'll sometimes get wear that you can't eyeball, but the grinding noise goes away after a short while as chain, ring and cassette mesh together.

2. There's a lube issue, since the new chain has a wet lube and there I had been using a dry lube on the old chain. I see a bit of dirt buildup which myght be caused by this. Will clean and be sure.