I'm switching my Shimano Tiagra 12-30t cassette to an SRAM 1070 11-32t for the broader range. My bike is a 2012 Trek 4.5 Madone.
Having reviewed a couple of youtube videos on the replacement, I think I understand what I need to do. However, some of the videos include a spacer in the switch while others do not. Can anyone tell me whether a spacer will be required for my switch and, if so, which one I need to buy? How can I determine whether I need to add or remove a spacer?
Finally, will adjustment to the RD be required, or will the switch be seamless between the two? I would like the keep the old cassette on another wheelset (set up differently for a more bombproof ride), but I would want to be able to switch out the wheelsets without adjustment, or it's just more trouble than it's worth to me.