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Old 09-26-10, 07:46 PM   #1
joyriding
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Adjusting the front derailler

So being pretty new to bikes, I decided to fix something that has been annoying me since I got this bike: I can't shift to the third gear in the front derailler.

I successfully adjusted the rear derailler, and I spent about 2 hours trying to fix the front. I found two strange things, the first being that the barrel adjuster on the cable to the front derailler seems to be broken and two, the range on the shifter doesn't seem to be enough to cover the range from first to third gear. I pretty much have to sacrifice the first gear to use the third, or vice versa, because even with both high and low limit screws completely loosened, the shifter only reaches from the third to the second, or the second to the first (and I mean clean shifting). It *almost* reaches the far gear, but doesn't downshift/upshift properly to it. I don't really use the first gear, so I set it up for 2nd and 3rd, but it still annoys me that I can't fix it.

This is an 18spd Univega Alpina Pro with Shimano Deore components (front cogs are biopace, if it matters).

Any ideas?
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Old 09-26-10, 07:52 PM   #2
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What short of shifters?
You say that with the limit screws all the way loose, you can either shift from the large to the middle or the middle to the small, but not into all three rings. How do you determine which two you're shifting between?
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Old 09-26-10, 08:04 PM   #3
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Yeah, what kind of shifters and what kind of drive train.
I recommend that you go to the www.parktool.com site and go through the instructions for setting up and adjusting a front derailleur. Do each of the steps in proper sequence leaving nothing out.
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Old 09-26-10, 09:36 PM   #4
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The cable should be just slack when you are in the lowest gear with the derailleur resting on the stop. Shift into the middle if that is all it will go then try pulling the cable directly where it runs along the downtube to get it to shift to the big ring. It should be stopped by the adjustment screw. If it shifts to the big ring for some reason your shifters aren't pulling enough cable. I assume this is a mountain bike? I have seen a lot of those shifters fail. You can replace the front with a friction thumb shifter and it will work fine for about $5 or get a new rear shifter as they are hard to rebuild. You could try cleaning it out if it is dirty with Blaster and pull a cable back and forth by hand once in a while it works. Ron
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Old 09-27-10, 12:11 AM   #5
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Quote:
Originally Posted by storckm View Post
What short of shifters?
You say that with the limit screws all the way loose, you can either shift from the large to the middle or the middle to the small, but not into all three rings. How do you determine which two you're shifting between?
Where I anchor the cable at... if I do it the right way and anchor the cable after adjusting the low limit screw, it only shifts up to the second gear. If I purposely anchor the cable while holding it over the second gear, it will shift up to third gear.

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Originally Posted by ronp6 View Post
The cable should be just slack when you are in the lowest gear with the derailleur resting on the stop. Shift into the middle if that is all it will go then try pulling the cable directly where it runs along the downtube to get it to shift to the big ring. It should be stopped by the adjustment screw. If it shifts to the big ring for some reason your shifters aren't pulling enough cable. I assume this is a mountain bike? I have seen a lot of those shifters fail. You can replace the front with a friction thumb shifter and it will work fine for about $5 or get a new rear shifter as they are hard to rebuild. You could try cleaning it out if it is dirty with Blaster and pull a cable back and forth by hand once in a while it works. Ron
Yep, this is exactly it, the shifter isn't pulling enough cable, I didn't realize it was so common. I guess I'll just replace it or something.
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Old 09-27-10, 02:48 AM   #6
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The shifter wasn't in the middle chainring position when you attached the cable to the derailleur with the chain and derailleur set up on the small chainring was it. Put a little bit of tension on the cable when the derailleur and chain is on the small chainring then click the shifter to downshift and see if any more cable out can be let out.

Last edited by cobba; 09-27-10 at 03:48 AM.
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Old 09-27-10, 09:00 AM   #7
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Originally Posted by joyriding View Post
This is an 18spd Univega Alpina Pro with Shimano Deore components (front cogs are biopace, if it matters).
I'm wondering if, at some point in it's life, this bike has had it's shifters upgraded. An indexing front shifter doesn't speak the same language as a front derailleur that was designed for friction shifter use.
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