After stopping the problem I was having with the chain not getting onto the largest cog at the back with help from you guys (i.e. turn the screw on the low limiter - and turn it the right way!) I am now having another problem in that the gears aren't shifting properly. If I move up a gear I have to click the gears up twice to get it to shift one gear and then click down one (but the chain doesn't move down) so it is actually on the right gear - if this makes sense. The change of gears takes a few seconds and occassionally makes horrible clunking noises and even managed to make the pedals jump so much that my shoes came out of the clips! I don't have any problems with changing down gears. Any advice on how I can fix this? Cheers!