I can see how road shoes might be more efficient if you’re mashing away at the pedals and putting lots of power in, like in a sprint in a race. But if you’re just spinning along keeping the pedals turning, like 99% of the time, are they really massively more efficient?
I can see if you have comfort issues with MTB shoes, they are worth trying, but that isn’t a problem I have. I ride a fair bit, although not ‘proper road miles’ (about 5-6000km a year at the moment), and I’ve never had any hot spots or problems with normal SPDs, even on 100 mile+ rides. Never really done a really long ride though, I guess I might think differently if I had?
I guess also have a quite efficient pedal stroke from 7 years of primarily riding fixed wheels on flat pedals on unicycles. To be honest I don’t find SPDs massively more efficient than flats, although they are jolly nice when you’re spinning like mad down a big hill.
Joe