I have 1999 Shimano XT cranks + a shimano UN51 bb . is it possible to adjust the chainline w/this setup? the crossover gear( big to big ) is way off . When I'm in the granny gear I only use the 3 largest cogs , so I'd be happy to give up the 5 smaller cogs. If it's not possible , what square taper BB's are available with the ability to adjust the chanline?