Do spike sizes really matter in cross country.? Like if I use 3/8 needle spikes instead of 1/4's, will I see an improvement in times. My coach told me that I should switch to 3/8's for the state meets because they are larger; they will allow me to climb up long hills faster and I may see drops in my times. I've only use 3/8's twice before and I didn't see THAT much of a difference in anything, but the courses I ran were relatively flat and not much hillage was involved.