Wwith a double or triple front mech one always had the ability to get a decent straight chain line front to rear utilising all the cogs through the range. ie in a 3 x 9 set up small front chain wheel aligns with the 3-4 larger rear cogs, middle front chain wheel aligns with the centre 3 rear cogs and largest front chain wheel aligns with 3 smallest rear cogs.

Now with the prevelance of single front mechs and 10 speed rears what problems are there with maintaining a good chain line and clean running in all gears since there will still be an otpimum front to rear chain alignment position?

Having found that NW rings tend to grind a bit when muddy, Ive moved to a misaligned BB to compensate. Moving a spacer from drive to non drive (if you have HTII) works a treat as long as you have the chain stay clearance to do it. Also I have found you really need to start using a dry lube if going 1×10.