drivetrain funkiness i can't figure out
05-30-11, 08:55 PM
#1
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drivetrain funkiness i can't figure out
Working on a friends lower end Trek, I have-
replaced the cassette
replaced the chain
removed/lubed the freehub body bearings
replaced rear shift cable
Here's the problem now-
When pedaling, there is a crunching/popping feeling coming from the rear of the drivetrain.
But only when in the third gear on back. It happens when using any of the chainrings. All of the other gear combos work great.
Any ideas? I was a bike mechanic for 12 years, and have never come across this.
replaced the cassette
replaced the chain
removed/lubed the freehub body bearings
replaced rear shift cable
Here's the problem now-
When pedaling, there is a crunching/popping feeling coming from the rear of the drivetrain.
But only when in the third gear on back. It happens when using any of the chainrings. All of the other gear combos work great.
Any ideas? I was a bike mechanic for 12 years, and have never come across this.
05-31-11, 11:45 AM
#3
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Did you overhaul / adjust the hub , check the bearings ? Are the cones in good shape ?
05-31-11, 12:01 PM
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Bad Cog?
Does the cassette have a bent, broken, or misaligned cog? Adjacent spacers not shaped right or misaligned?
05-31-11, 12:47 PM
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if it's only on the 3rd cod, the sound is most likely the result of the cog being misaligned or having a tweaked tooth, or possibly some interaction with the chainline (doubtful) or derailer pulley when lined up with the 3rd cog (even less likely).
easiest way to start testing is switch the freewheel to another with the same speeds/spacing and see if that takes care of it. (I'm assuming this is a freewheel on this bike)
easiest way to start testing is switch the freewheel to another with the same speeds/spacing and see if that takes care of it. (I'm assuming this is a freewheel on this bike)
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"c" is not a unit that measures tire width
"c" is not a unit that measures tire width
05-31-11, 09:28 PM
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I have no other wheel or cassette to swap, it's an 8 speed and all of mine are 9.
Actually, I guess I could put the 8 speed cassette on one of my wheels and try it.
I did overhaul and adjust the hub. Everything was fine.
The cassette is brand new, and the 3rd gear looks perfectly straight when spinning the wheel.
Actually, I guess I could put the 8 speed cassette on one of my wheels and try it.
I did overhaul and adjust the hub. Everything was fine.
The cassette is brand new, and the 3rd gear looks perfectly straight when spinning the wheel.
06-01-11, 10:19 AM
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when you installed the chain did you make sure that the link is not so tight that the chain sticks in position coming off of the top pulley??
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joejeweler
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06-28-12 11:57 AM
