cafzali

First, realize that a phrase like a "long ride" may seem intuitive to you, but actually means a lot of different things, depending on one's ability and experience. For example, if you can do 20 miles easily now but are finding a lot of pain and mental fatigue trying to go longer, that's one thing. If you can't do rides of that length to begin with, that's another.

If you can do short/medium-length rides without pain, then going beyond that's just a matter of training. If short rides are taxing, you may also want to do some exercises to improve your core strength, like squat jumps and split squads, which are great at building muscles that don't get enough work on a bike. Even if you can't swing the funds for some personal training, getting an assessment from a qualified coach may be beneficial.