Will this effect top end or gearing? if so how much? my bike is geared -1+2

its around 1 tooth up in the back or so. Bike will also turn in a little slower. speedometer will read a little higher than before

I wouldnt worry about turn diff,i would how ever get a speedo healer cause you will rack up more miles that you are not actually rideing with smaller tire.. Drop a lil preload or drop forks in the tripples 3-5 mm or shim up the rear that same amount and it will be back to same as a 55...OOORRRRR save all the bs and get a 55 on back again..

what brand tire are you looking to get ?

got a dunlop q2