How do you fine tune a Shimano rear derailleur?
Use the barrel adjuster to fine-tune its position. Turning the adjuster anticlockwise increases tension on the cable, bringing the derailleur closer to the wheel; clockwise decreases the tension, moving it back towards the frame.
Can you use wd40 on bike chains?
All you need to do is rinse the bike chain to remove any mud and thick dirt. Spray the WD-40 Bike Degreaser onto the surface of your bike chain and give it adequate time to work. On top of that, the WD-40 Bike Degreaser can be used for the cleaning and degreasing of other moving parts as well.
What does the B screw do on a rear derailleur?
B-Screw. Most derailleurs have some form of adjustment for the spacing of the guide pulley to the cogs. This spacing is controlled by the B screw, or body-angle screw. This adjustment is check when the chain is on the smallest sprocket up front, and the largest cog in back.