Bicycle Mechanics - Tiagra left shifter Pop/Crunch sound

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malux
09-30-10, 07:36 AM
I snapped my FD cable last week and had my LBS replace the cable. I'm hearing a pop/crunch sort of noise from the left shifter. Is there anything I should be looking for?

Also, I'm having trouble shifting into the top gear on my RD. LBS said they adjusted it; it was ok for a day or two but now back to the same issue...

The bike is a 2008 trek madone 2.1. Tiagra for the FD and Shimano 105 for the RD.


scruggle
09-30-10, 08:14 AM
I snapped my FD cable last week and had my LBS replace the cable. I'm hearing a pop/crunch sort of noise from the left shifter. Is there anything I should be looking for?

When do you hear the noise? When you shift up, down, both, or neither? Does it happen every time, or intermittently?

malux
09-30-10, 11:34 AM
When do you hear the noise? When you shift up, down, both, or neither? Does it happen every time, or intermittently?

i hear it every time I shift into the climbing gear. It's when I'm shifting using the smaller lever (what is the correct name for that?) not the brake lever.


scruggle
10-01-10, 02:04 PM
Well, you can hear a 'pop' or mild 'bang' when you shift into the small chainring, since you're letting the tension out of the cable in one go. I don't know if it's different than what you had before. As for a 'crunch' noise, that seems quite odd. You're not shifting under load, are you? Sorry if I can't help any more, maybe this bump will get someone's attention.

As for the top gear on your RD (I assume you mean the smallest cog), there's no reason in principle why it shouldn't work with the components you have. When it doesn't work are you are using your small ring up front and the small cog in back? That may cause trouble - there may be a trade-off between removing cage-rub from the FD and getting your smallest chainring to cooperate with your small cog (which you probably don't need to use anyway). Perhaps the more experienced BF minds can help out. At any rate, there is a basic run-through on how to adjust indexing at http://www.parktool.com/repair/readhowto.asp?id=64 and it's non-destructive (see also the links to other adjustments).

malux
10-04-10, 07:12 PM
i ended up taking it to my LBS. A little lube and a little tweak in the tension and it seems to be ok now. Good thing I took it in, my crank was a bit loose and i was a getting a little creak they were able to fix up.

as for the RD, i was never cross chaining and a little adjustment took care of the problem. i really need to learn how to make these small adjustments myself...