Bicycle Mechanics - Trek Fuel 100 Chainline Problems

Hello Everyone:
I have a Trek Fuel 100 (2003) with the XTR groupo. I have a terrible time seeting it up so that i can shift to the granny gear. I bought the bike used last year and it had one spacer on the non-drive side and no spacer at all on the drive side of the cranks. Trek recommended me to move the spacer over to the drive side to bring the chainrings out a bit. The front deraileur is set up to pivot all the way in (maximum limit) but I still have trouble shifting down to the granny. It looks like the chainline is quite far out to the right so i don't think i should space it out even further to make it shift. I suspect that by moving the crank out to the right created another problem. I frequently drop the chain from the big ring down to the middle, or middle to granny (unintentionally this time) especially when the suspension is active. I never run the extreme cross over chainlines so that should not be the problem. I have tried new drive train, different brands of chains (Shimano works best so far) and fine tuned the adjustments of the deraileur but without success. Does anyone have any suggestions for remedies to solve these problems. Trek customer support suggested that i tried their micro adjustable bushings for the lover pivot. I have yet to try that option.

/Dave

First off, you need to check your chainline. Check sheldon brown's excellent website for pictures and a very good explanation of how to do this: http://sheldonbrown.com/chainline/index.html. Your chainline measurement should be AT LEAST 47.5mm. If it is less than this, the bottom bracket and bottom bracket spacer need to be changed to get that middle ring between 47.5mm and 50mm.

Now, after your chainline is correct, you need to check the alignment of the swingarm. Shift the bike into the middle chainring and into the middle cog. The chain should be in a pretty straight line when you sight down it.

Finally, use the string method to see if the rear end is centered on the frame:
http://www.sheldonbrown.com/frame-spacing.html

Sheldon explains the string method in the link above nicely. I recommend leaving the rear wheel in when you use the string method. If the rear end is out by more than 2mm, you will have to rotate the microadjust bushings like trek said.

Let me know how it goes. I have some tips for working with the microadjust bushings too.

Thanks for the info. I will look into all your suggestions as soon as I can.
/Dave


First off, you need to check your chainline. Check sheldon brown's excellent website for pictures and a very good explanation of how to do this: http://sheldonbrown.com/chainline/index.html. Your chainline measurement should be AT LEAST 47.5mm. If it is less than this, the bottom bracket and bottom bracket spacer need to be changed to get that middle ring between 47.5mm and 50mm.

Now, after your chainline is correct, you need to check the alignment of the swingarm. Shift the bike into the middle chainring and into the middle cog. The chain should be in a pretty straight line when you sight down it.

Finally, use the string method to see if the rear end is centered on the frame:
http://www.sheldonbrown.com/frame-spacing.html

Sheldon explains the string method in the link above nicely. I recommend leaving the rear wheel in when you use the string method. If the rear end is out by more than 2mm, you will have to rotate the microadjust bushings like trek said.

Let me know how it goes. I have some tips for working with the microadjust bushings too.