Hello.. I need help. I have never done anything to a bike in my life. Recently I gained possession of an adult three wheel, older model, 70's? Schwinn tricycle (for my handicapped son). Good shape but the tires were shot. I bought new ones. I successfully changed the front tire and the left rear (left, facing the trike) The right tire is on a wheel (I think called a bendix?) and that wheel has it's own little chain on it, besides the big chain running down the mddle. It also has a wire running into it and that wire goes the length of the trike up to the handle bars and a little switch (gear?). I took off the nuts and washers (like I did the other wheels) but it is still stuck onto the trike. Do I need to get that wheel completely off or can manuever the old tire off and the new on between the frame? I don't know what to do next to get that wheel off. I don't want to mess it up. GO easy on the bike terminology please, I am a girl with no experience.