I'm a relative newbie to adjusting derailleurs...but I decided to tackle it this morning as my Deore XT-equipped HiFi Pro has been shifting like crap lately.
I've been following what appears to be an excellent guide to adjusting derailleurs by Park Tool...
http://www.parktool.com/repair/readhowto.asp?id=64
I figure these guys know what they're doing. I first let all the tension out of the inner wire (as instructed by Park Tool) and carefully set the low- and high-limit screws. No problem there, that went smoothly.
Then (again, according to the Park Tool instructions) I shifted to my smallest cog (and outermost chainring) and checked the shift to the next innermost cog. It didn't happen (of course, 'cause I'd let all the tension out of the wire)...so Park Tool said to add 2 full turns of tension at the barrel adjuster by the shifter, then try the shift again. Still didn't shift, but closer. Park Tool said keep tensioning the inner wire in 1/4-turn increments until the shift happens. I did, and it did.
Then Park Tool said to shift to the 2nd smallest cog...then keep adding tension to the inner wire (in 1/4-turn increments) until I heard rubbing noise...then back off. The basic procedure called for shifting inward one cog at a time, increasing tension, then backing off (but not going all the way to the innermost cog with the chain on the outermost chainring, obviously).
This is when things got completely random. No matter what I do with inner wire tension, I keep getting random results, mostly when shifting back down to the smaller cogs.
For example, I'd shift up (to a larger cog) with one click...but then clicking once to reverse (shift back to a smaller cog) nothing would happen. So I'd click a 2nd time, and the shift would happen.
This is why I started going nuts. Even after riding this bike for a year, I don't think I have a solid baseline for what my shifters and derailleur are SUPPOSED to do (e.g. what's NORMAL?)
THE BIG QUESTION: With a Deore XT derailleur, should there be a 1-to-1 ratio between "UP" clicks (of the shifter) and "DOWN" clicks? Or is it normal to click once to shift to a larger cog (up)...but then have to click TWICE to shift back to the next smallest cog?
What makes it all more maddening is that I realize it's normal (I think) to have to press the shift lever a little ways PAST the "click" when shifting to larger cogs. Park Tool even says this, saying that every bike and derailleur differs in this regard (in terms of how far past the "click" you might have to go to make the shift happen).
But what I don't know is how far past the "click" is normal?
It's all frustrating because it's so difficult to achieve some kind of 100% repeatable actions.
Any tips are much appreciated!
Scott
I've been following what appears to be an excellent guide to adjusting derailleurs by Park Tool...
http://www.parktool.com/repair/readhowto.asp?id=64
I figure these guys know what they're doing. I first let all the tension out of the inner wire (as instructed by Park Tool) and carefully set the low- and high-limit screws. No problem there, that went smoothly.
Then (again, according to the Park Tool instructions) I shifted to my smallest cog (and outermost chainring) and checked the shift to the next innermost cog. It didn't happen (of course, 'cause I'd let all the tension out of the wire)...so Park Tool said to add 2 full turns of tension at the barrel adjuster by the shifter, then try the shift again. Still didn't shift, but closer. Park Tool said keep tensioning the inner wire in 1/4-turn increments until the shift happens. I did, and it did.
Then Park Tool said to shift to the 2nd smallest cog...then keep adding tension to the inner wire (in 1/4-turn increments) until I heard rubbing noise...then back off. The basic procedure called for shifting inward one cog at a time, increasing tension, then backing off (but not going all the way to the innermost cog with the chain on the outermost chainring, obviously).
This is when things got completely random. No matter what I do with inner wire tension, I keep getting random results, mostly when shifting back down to the smaller cogs.
For example, I'd shift up (to a larger cog) with one click...but then clicking once to reverse (shift back to a smaller cog) nothing would happen. So I'd click a 2nd time, and the shift would happen.
This is why I started going nuts. Even after riding this bike for a year, I don't think I have a solid baseline for what my shifters and derailleur are SUPPOSED to do (e.g. what's NORMAL?)
THE BIG QUESTION: With a Deore XT derailleur, should there be a 1-to-1 ratio between "UP" clicks (of the shifter) and "DOWN" clicks? Or is it normal to click once to shift to a larger cog (up)...but then have to click TWICE to shift back to the next smallest cog?
What makes it all more maddening is that I realize it's normal (I think) to have to press the shift lever a little ways PAST the "click" when shifting to larger cogs. Park Tool even says this, saying that every bike and derailleur differs in this regard (in terms of how far past the "click" you might have to go to make the shift happen).
But what I don't know is how far past the "click" is normal?
It's all frustrating because it's so difficult to achieve some kind of 100% repeatable actions.
Any tips are much appreciated!
Scott
