Bicycle Mechanics - Shifting to Large Rear Cog
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02-23-07, 01:58 PM
I just got finished switching all of my components over to a new frame. Everything went on fine. I simply re-used the former cables and housing (they were brand new on the old frame). I noticed that the spacing between the rear derailleur and the rearmost cable stop was slightly longer on this frame however. I tried to use the old housing, and had to bend it pretty severely to get it to work in the new set up. Its probably a few inches too short. Coincidentally (or not) I am having a difficult time getting the derailleur to shift onto the largest rear cog. My limit scews are fine. Could this problem be caused by the severe bend in the cable housing near the rear derailleur? I don't happen to have a longer peice of cable on hand, so would have to order it. I notice the shifting in general is a little slower and less responsive, almost as it is hesitating before shifting. Do you think a longer peice of cable could solve this, or could it be something else that I am overlooking?
Yes, that can mess with performance a great deal. Housing is cheap, so I would replace it ASAP.
02-23-07, 02:02 PM
Yes, if the cable was too short and you had to bind the housing it will affect shifting. Is this index shifting?
Could also be a bent derailure hanger on the new frame.
02-23-07, 02:10 PM
Yes, it is index shifting. I have an Ultegra 9 speed set up that was working flawlessly the day before I switched over to the new frame.
I can't imagine that the derailleur or hanger were bent. If it was bent, to make it difficult to shift onto the large rear cog, I assume that it would have to be bent away from the center line of the frame, and not pushed back in toward the frame right?
02-23-07, 02:13 PM
I would be more ready to blame the cable than a bent hanger at this point. Index shifting is sensitive to the rear housing being right. Replace the cable and readjust everything, if it still has problems then you might want to check other things like a bent hanger etc.
Proper cable housing length and routing is important.
02-24-07, 02:23 AM
IF the cable was too short, wouldn't that cause it to not want to shift to the smallest cog?
02-24-07, 08:18 AM
Get yourself a new shift cable and housing.
That short piece of cable housing that's adjacent to the rear derailleur is one of the most common problem areas on a bicycle.
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