Its a 1 1/8" threadless set-up. Not sure of the stack height, but there's plenty of steerer tube sticking up above the top of the 145mm headtube so that won't be a problem. I was thinking of just using a Cane Creek 40 series headset (a pretty generic headset). Also thinking I might even buy a new suspension-corrected fork (Nashbar has one for $49) that would raise the front end a little, which I'd like.