Frame size depends on the type of trike but should always match your height and inseam length. Ideally, the frame size should be 0.65 times your inseam. So, if your inseam length is 25 inches, get a frame that’s 16 inches long. To help you get the right size, go over the frame sizing chart provided by the trike manufacturer. You can also just opt to get trikes with adjustable frame lengths and handlebars that can be easily adjusted to match your body size.