Bicycle Mechanics - Deore front derailleur does not go back to small cog

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carcassonne
02-10-07, 07:16 PM
Folks,

This is the oddest thing I've seen. The Deore front derailleur can climb from the smallest chainring to the largest, but cannot go back to the small chainring. The shifter is SRAM.

Or am I doing something fundamentally wrong ? I've taken off the front derailleur to clean it. It was not shifting back to the smallest chainring at that time so I tought that by cleaning it (winter riding, lots of goo, mud, white stuff) ti would function properly again. Maybe I'm installing it not right:

I put the shifter on the low '1' position and then I tension and hook the cable tot he derailleur. Whne the shifter goes to 2 and then to three 3 the cable pulls on the derailleur and makes it move to the largest chainring. But when shifting back to '1' it won't go back to the smallest chainring.

Any idea ?

Cheers.


uphillbiker
02-10-07, 08:58 PM
This is just a guess, but I just got finished tuning my derailleurs this evening. Perhaps the point where you connect the cable to the derailleur needs to be adjusted so that when you shift up, the chain is not pushed out as much. My problem was just the opposite. I could get down from 2nd to first quickly, but could not get back to 2nd from first easily and just about could not reach 3rd. A little tuning of the cable connection solved the problem. It might also depend a good bit on the riding you do, whether you'll spend the majority of your time in high gear or low gear as to the exact adjustment.

Shredder3034
02-10-07, 09:22 PM
Folks,

This is the oddest thing I've seen. The Deore front derailleur can climb from the smallest chainring to the largest, but cannot go back to the small chainring. The shifter is SRAM.

Or am I doing something fundamentally wrong ? I've taken off the front derailleur to clean it. It was not shifting back to the smallest chainring at that time so I tought that by cleaning it (winter riding, lots of goo, mud, white stuff) ti would function properly again. Maybe I'm installing it not right:

I put the shifter on the low '1' position and then I tension and hook the cable tot he derailleur. Whne the shifter goes to 2 and then to three 3 the cable pulls on the derailleur and makes it move to the largest chainring. But when shifting back to '1' it won't go back to the smallest chainring.

Any idea ?

Cheers.
Here's how I would approach the situation.....remove the cable from the deraileur and hold it taught in your hand. Then activate your shifter and see if your shifter returns the cable under the pressure you apply. Remember, the shifter has two mechanisms which shift and release the cable so, it is possible you might have a broken spring in your shifting mechanism. Try it and get back to me...Peace!


Retro Grouch
02-11-07, 04:23 AM
The exact position of your front derailleur on the seat tube is critical. Since you say that you took it off to clean it, my guess is that you didn't get it remounted in exactly the right position.

Goto parktool.com. They have a good set of step-by-step directions for setting up your front derailleur. Disconnect your shift cable and start at the very beginning just as if you were installing the derailleur for the first time. My bet is that'll fix it.

onbike 1939
02-11-07, 06:20 AM
The most obvious cause would be that, you've overtightened the cable which would prevent it from releasing the mech back to the small ring. I daresay you will have checked this however.

Portis
02-11-07, 08:03 AM
http://www.parktool.com/repair/readhowto.asp?id=75

carcassonne
02-11-07, 12:13 PM
Folks,

I got it, but I'm not sure exactly why ;-) Taking a closer look I
saw that the cable casing was getting out of the shifter when
trying to go back down from the highest chainring. Instead of
the inner cable release, the actual housing was getting out of
the shifter. I guess it meant that the cable was kinda stuck
somewhere. Maybe the gooey winter stuff or something.

So I replaced the cable, adjusted a bit, and it shifts OK now.
I've put a good amount of teflon oil on the cable. The shifting
is a bit hesitant, but that's how far I got by this winter temp
in the garage with barely a small heater trying to warm up the
air. Not to mention the ground and cold feet. For all puposes it
shifts OK, so I could as well keep it like this until spring. Or
I might spend an extra 15 minutes later.

I did try it in some snow, though. Before that fix I was stuck
on the large chainring. Now, getting it all the way down to the
small chainring and the largest at the back makes it a lot of fun
in deep snow.

Cheers.