Ok, but for those of us that like to ride flats……any suggestions.
A less facetious answer than my one yesterday…..
On a mountain bike what makes a great flat shoe and pedal combo is ‘stiction’ – the shoe being really fixed to the pedal by sticky rubber and good pins. Obviously big upsides like foot security. The downside is no float – your foot is pretty much unable to rotate. I don’t think that’s much of a drama on a mtb because it all so dynamic – you are up and down out of your saddle, maybe dabbing from time to time, basically you are all over the place. Gravel bikes are much more like road bike – much more passive riding position and a regular metronomic repeated cadence for long periods of time. That’s the sort of riding the float of an SPD really helps in avoiding hotspots and aches as well as knee niggles. In many ways a good secure mtb might make a bad gravel setup.
So to be honest, counterintuitively, the best flat setup for gravel might be to go for something less impressively sticky/grippy than the ubiquitous fiveten and use a bog standard trail running or walking shoe that’ll move around a bit more on the pedal. That will of course make it feel less secure…..Or of course go down the spd route and enjoy a bit more floaty goodness whilst still having the security of the clipped element in the rougher stuff.