I've reached the point in my noob build/fixie where I must acquire the 1 1/8'' threadless headset. I really can't afford or even require a high end; Hope, Chris King, etc, so have been looking at Ritchey & Cane Creek as well as others. My question is this: Most of the units I've looked at are spec'd for mtb use, but suggest they can also be used for road bike use. What distinguishes a 'road' headset from that for a mtb? Should I avoid those units spec'd as suitable for either bike? Thanks in advance for any advice your experience can afford me....