the cams(actully wheels) are the PSE stage three cams and they are basically a round wheel with the axle mounded on the out side edge,,the reason the 2315 are 31" is because i bought them from walmart and in order to get them at that size they had to be 31" and as i dont have, or have access to a arrow saw to cut them down i left them there,,thought about useing copper tubing cutter to cut them down but could not find the insert i needed at gander mnt. or bass pro in st.charles MO.