Was having some funky shifting (indexing really) after cleaning the chain and rear casette this week. Read Sheldon Brown's tips on adjusting the rear derailleur and got everything shifting fine again with just an adjustment to the cable tension (barrel).
However, when in low gear it would make a clunking noise. Turns out the jockey pulley was hitting the low gear. Turned the B screw in about 2 turns and it fixed it.
My question is, why would this suddenly go out of adjustment? Is something else out of wack? The alignment looks perfect. Or is it possible it was never right to start with? I have about 1200 miles on the bike since new last year...
This is a Shimano 105 set on a Specialized Sectuer Comp.
Curious more than anything. There is not much left on the B screw for threads (almost all the way in), but the low gear is only a 27 tooth, so that is not excessively low.