I need to move the chainline out, but I'm not sure how much.
To make a long story short; this bike had chain suck problems from the get-go. I went back and forth with the lbs. After about 6 return visits they finally swapped out/upgraded the chainrings. That fixed the chain suck problem.
Now the chain rubs the inside of the derailler cage when in low gear - and YES I have adjusted the limit screw.
*When in low gear the chain rubs the cage. It rubs hard.
*When in low gear the chain is very close to the back tire. If I ride through any mud at all the chain scrapes it off the side of the tire.
*There is very little clearance between the large chainring and the chain stay.
I figure if I switch to the 126mm bb cartridge then the chainline will be moved outwards by 4mm. And yes, this is a wild a$$ guess.
How else can I tell where the chainline should be?
I thought that if I could measure the distance from the large chainring to the frame (seattube) on an unmodified bike, that would tell me how far the chainring should be from the frame and I could adjust accordingly. The bike is a 2011 Rockhopper with 26" wheels.
In case you are wondering, I am done messing with the LBS on this issue. I'll just eat the cost of the new bb cartridge. I think they are $16.
more cops have been killed by donuts than guns in chicago it is a medical fact ask any doctor.