Many bikes and trikes are equipped from the factory with 170mm or 175mm cranks. These are great for the long-legged or those of us with super human kneecaps, but for most people, they are a bit too long. Easy Knees Crank shorteners allow you to expiriment with your crank arm length before committing to a pricey new crank set. Crank shorteners can also be used to accomodate legs of different lengths.
If your legs are the same length, but maybe your knees aren't as good as they used to be, a shorter crank arm can help alleviate some of the strain.
If you have one bad knee or have limited range of motion in just one leg, check out our Easy Knees Pedal Swing. It is designed to help you find the right pedal stroke for each leg instead of compromising on a single adjustment that doesn't truly fit either leg.