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Discussion Starter · #1 ·
I run a compact crank (50-34) and a 12-27 cassette; lots of hills where I live.
Anyways, I leave the crank in the small ring all the time. This weekend I decided to try to shift to the bigger ring for the heck of it but nothing happened. What gives?
 

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More info?

Perhaps you can fill us in on what happens when you shift. Does the lever move, is there rattling as if it was trying, is the cable super taught or very limp.
 

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Discussion Starter · #3 ·
Sorry - good call.
So when I shift the lever, it moves and I hear a slight rattle and that is about it. I look down and the chain is still on the small ring. The cable is definetly not limp. Should the chain move up to the big ring?
 

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jrchan said:
Sorry - good call.
So when I shift the lever, it moves and I hear a slight rattle and that is about it. I look down and the chain is still on the small ring. The cable is definetly not limp. Should the chain move up to the big ring?
Wasn't that the goal? :D

Even though you say the cable is not limp, I'm thinking it is when you're in the smaller chainring. If so, it's nothing more than cable stretch and you can adjust that out with the inline adjusters. If not, then possibly the cable and/ or derailleur is 'frozen' (from lack of use/ corrosion/ dirt). Another possibility is that the 'H' limit needs adjustment (see link), but that seems less likely.
http://www.parktool.com/repair/readhowto.asp?id=75
 

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It could be excess cable slack when the shifter is in the lower ring position or it could be the limit screw for the big ring isn't adjusted correctly.

As for the rear deraileur handling a 12-27, is there a shifting issue like hesitation or were you just having front issues? Without seeing or knowing more I'm going to say a 12-27 should work with a short of mid-cage deraileur.
 

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PJ352 said:
Even though you say the cable is not limp, I'm thinking it is when you're in the smaller chainring. If so, it's nothing more than cable stretch and you can adjust that out with the inline adjusters. If not, then possibly the cable and/ or derailleur is 'frozen' (from lack of use/ corrosion/ dirt). Another possibility is that the 'H' limit needs adjustment (see link), but that seems less likely.
Here's how to test. With the bike on a stand (or have somebody hold it up so the rear wheel is off the ground), turn the cranks slowly while you try the shift. If it doesn't complete the shift after you've moved the lever all the way, try to push the derailleur cage with your hands (watch out for your fingers) and see if you can make the chain move onto the big ring. If you can't, either the high-limit screw is improperly adjusted, or something in the derailleur itself is stuck.

If you can make it shift this way, then you just have too much cable slack, and you need to adjust it. There might be enough room in the adjusters, but if there's not, you have to detach the cable from the derailleur and take out some slack. It's not difficult. The Park Tool instructions that PJ linked to explain it pretty well, but this article by Sheldon might also help.
http://www.sheldonbrown.com/derailer-adjustment.html

I run a compact crank (50-34) and a 12-27 cassette; lots of hills where I live.
Anyways, I leave the crank in the small ring all the time
That's interesting. Do you really like to spin fast, or do you just coast down the hills? If you stay in that 34 small ring, your highest gear (extreme cross-chain 34x12) would have you spinning about 145 rpm at 30 mph. Maybe you don't go that fast, but as long as you have all those gears you might as well use them. Otherwise, you could just join the fixed-gear crowd ;-)
 
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