I have small (5.5-6.0) feet, which are medium width, with a narrow heel. But I have a bunion on my left foot and both feet swell when it gets hot (when i am riding). I wear Sidi Dominators (like Denise), but they do come in 'mega" width. So, normally i would wear a 36 in regular shoes and I bought 38 megas for my road shoes. The rachet makes a difference, so you can losen as you ride. This is also good for winter riding, when I wear woolie bullies. My mountain shoes are also Sidis, but they don't have a rachet and are 37s. (regular). They are fine for spin class, but if it's hot and I'm mountain biking, it can get uncomfortable.