If you go longer your handling is affected, (same for shorter too only different). The difference is that with longer shocks the bike turns faster (quicker turn-in), shorter the bike turns slower (i.e. give me 40 acres and I'll get this beast turned around). It has to do with the fork trail, which has little to do with the tire unless the tire's aspect ratio changes trail. If you just want to keep the tire from rubbing the paint off the underside of the fender, stick with the 225 and put on whatever size shock you want.