Just really test what works for you.

I thought I just wasn't as strong a rider as the rest of my club... until the day I happened to eat a nice big lunch, with a couple of bowls of brown rice, on club ride day. All of a sudden I could hang with them and my legs weren't hurting Deliberately repeating the experiment has reproduced the results... if I have a big high-carb meal 3 hours or so before the ride, I am MUCH stronger. I would never have known if I hadn't tested it.