I have the 60-70 pse brute x and when i first got it, i could barely pull it at 60 pounds. I set it at 55 and shot for a while and with lots of weight lifting, i could finally get it back comfortably at 60 pounds. to answer your question, you can set a 60-70 pound pse at 55, but i wouldnt recommend any less. it probably wasnt a good idea for me to shoot it at 55, but i did with no damage to the bow.