You will need to either cut the steer tube or add a spacer. I'd go with the spacer option as its cheap and easy. You'll need the spacer to take the play out of the the system. Use the top cap bold to preload the bearings then tighten the bolts on your new stem to secure everything in place. If you are using a carbon steer tube, make sure that all the spacers are below the stem. I.E. no spacers on top of the stem. Hope this helps.