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Ok, a strange drivetrain noise puzzle. I got it after 3 tries.
My wife said her drivetrain was noisy. It sounded like the rear D was out of whack, and the chain was not setting right on the cogs, like the links were hanging on the teeth and then sliding into place. No problem, thought I.
So I set the cable tension and stops. I added just a bit of tension, and adjusted the lower stop just a smidge. Noise gone on the stand.
Not on the road.
Ok, second try. I rechecked the adjustment. Spot on. Lubed chain and checked for a stiff link (nope) and dug some gunk out of the cogs that MIGHT have been causing the chain not to seat properly on the teeth. Looked like sticks, turned out to be flimsy plant material.
Nope, noise on the road, still. Now it get's interesting. We rode, and I listened. The noise was bad in the 3rd easiest cog. It was totally silent in all other combinations, at least in the middle ring. But the noise was definitely from the cogs and not the rings. Also, the noise was under pressure of acceleration, pedaling at constant cadence on the flats meant no noise, but speed up or climb and the noise was back.
I fixed it very quickly on getting home.
Campy Mirage, 9 speed drive train.
What was wrong? Please explain WHY the problem only occured in the third cog. In other words, show your work!
My wife said her drivetrain was noisy. It sounded like the rear D was out of whack, and the chain was not setting right on the cogs, like the links were hanging on the teeth and then sliding into place. No problem, thought I.
So I set the cable tension and stops. I added just a bit of tension, and adjusted the lower stop just a smidge. Noise gone on the stand.
Not on the road.
Ok, second try. I rechecked the adjustment. Spot on. Lubed chain and checked for a stiff link (nope) and dug some gunk out of the cogs that MIGHT have been causing the chain not to seat properly on the teeth. Looked like sticks, turned out to be flimsy plant material.
Nope, noise on the road, still. Now it get's interesting. We rode, and I listened. The noise was bad in the 3rd easiest cog. It was totally silent in all other combinations, at least in the middle ring. But the noise was definitely from the cogs and not the rings. Also, the noise was under pressure of acceleration, pedaling at constant cadence on the flats meant no noise, but speed up or climb and the noise was back.
I fixed it very quickly on getting home.
Campy Mirage, 9 speed drive train.
What was wrong? Please explain WHY the problem only occured in the third cog. In other words, show your work!