It's amazing how much a few pounds can make. I struggle with 70 lbs. I can only pull it about 4 or 5 times, and never pull it smoothly. I can pull 65 lbs smoothly about 6 or 8 times and then I start getting shakey. I can pull 62lbs almost all day long. I don't understand how just a few pounds makes such a difference, but it does.