Bicycle Mechanics - XT 8 speed adjustment

The Sachs grip shift finally crapped out on me completely and I found myself some 8 speed XT shifters. I've got them installed but I can't seem to get them adjusted perfectly. If I get the front deraillieur to shift up through the larger sprockets it won't do it down and vice versa. This was working correctly before I put the new shifters on so I'm pretty sure it's not the derailleur that is failing.

I'm using the Barnett's manuals as a guide. Maybe I'm not quite comprehending the manuals and missing something but I've sunk a lot more time into figuring this out than the Barnett manuals claim is necessary. Any advice?

For a front derailleur, there are 3 basic adjustments:

1) derailleur cage alignment and height

2) limit screws (high and low)

3) cable tension

First, make sure the derailleur cage is parallel with you chainrings. Then adjust the height of the derailleur so that when it is shifted to the big ring there is about 3mm clearance between the cage and the largest chainring. Then roughly adjust the limit screws so that the derailleur doesn't throw the chain inboard of the smallest chainring or outboard of the largest chainring. Finally, loosen the cable fixing bolt and pull the slack out of the cable before retightening the fixing bolt. You can then try and run through the gears and adjust the limit screws further if necessary. If you happen to be in the Atlanta area I'd be more than happy to help you with any adjustments.

Gah! Roughly a 20 hour drive to Atlanta from Toronto...it might actually be faster ;). Your advice is noted and I will continue to tinker taking it into account. Supposed to rain the next few days so maybe I can get tuned before the sun comes out.

http://www.parktool.com/repair_help/FAQindex.shtml

I know this doesn't make any sense but I have to ask - are there any considerations I need to make when moving from a grip shift to a rapid fire? Derailleur height on the frame? As far as I can tell I have it set just like the Parktool instructions say and still no workie. :(

My advice to you is take it to your LBS and have them fix it.

Unfortunately not an option.

I would say then it is either one of three things. A defective front shifter, old cable and housing, or if you installed new a cable and housing there may be a bur in the housing, that will cause problems as the cable cannot slide smoothly.

I know this doesn't make any sense but I have to ask - are there any considerations I need to make when moving from a grip shift to a rapid fire? Derailleur height on the frame? As far as I can tell I have it set just like the Parktool instructions say and still no workie. :(

How old is your front derailleur? For your rapid fire shifter to work, you have to have a front derailleur that is designed to work with index shifting. I don't know how accurate this is, but somebody told me that the key factor to look for is the angle of the arm on the derailleur arm that the cable attaches to. You want there to be about a 90 degree angle between the arm and the cable.

Good luck. Hope this helps and the rain goes away so that you can ride.

I was informed by a lbs that the LX front derailleur I have is completely compatible with the XT shifters. The new shifters came with new cabling and housing both of which I used.

I'm guessing that it will take someone with more experience with this sort of thing just a couple minutes to get sorted. This is my first attempt at derailleur tuning.