it depends what you want i guess. I always stud the whole track, because it gives somewhat better hook up than just studding the center because the weight of the sled is distributed on the rails, so the outside has a lot of weight on it, but studding the outside also causes more tear-outs if you aren't smart with your traction. Spinning your track, sliding, etc, will put a lot of stress on those outter studs. So for durability in extreme conditions, studding just the center will be better. Just depends what you are looking for and how you ride