i just got myself a new canyon cf 7.0 road bike but it comes with a mtb slx cassette while the rest of the groupset is shimano 105.I don't need a 32t rear cassette so want to swap it for a ultegra 11-28t. will this be compatible or will i need a new chain or chain length or even a new rear derailleur.everyone talks about short cage and long cage.i am totally confused!