Hello. First off I would like to apologize if my questions are common sense, I have done my own research with some progress but with some stopping points that I hope to get pushed in the right direction here. I am trying to build a system that is similar to a bike with a free wheel so it can spin freely in one direction and engage in the other. The issue I am having is finding a way to change how much load is required to rotate the system without switching to different size gears to change ratios. When searching online, I found the Nuvinci continuously variable planetary drive which is what I think I would need to accomplish this. But I do no know if there is something better. There will be no motor to this system, it will use gravity as its drive. I will eventually want to be able to set the "weight" digitally or some other way that can allow for easy changes in the required weight to rotate the system, but my main priority is knowing what to look for. The minimum weight that I am trying to accomplish is 50 pounds, and the maximum 300. I understand that that may be a large gap so I realize the gap may need to be reduced, and if so I would raise the minimum rather than reducing the max. If any can help or tell me whether I am even searching in the right place here than I would greatly appreciate it. If anything is unclear or any more details are needed, please feel free to ask. Thanks you!