It's not clear if you are talking about a spin class/bike or your own bike on a trainer. If it's a spin bike, most have flats and toe straps on one side and SPD on the other, so MTB shoes would be the thing, I think they all take SPD cleats. If it's your own bike, and it doesn't have clipless pedals, then certainly get shoes, cleats, and clipless pedals of some sort. That said, MTB shoes with SPD cleats are by far the best for walking around by an order of magnitude. Just starting out, being shod with real bike shoes, even cheap shoes will be probably be as good as your 50 y.o. ones. Yeah, our feet, noses, and ears just keep growing. Also many of us figured out long ago that stylish shoes were not really in our best interest and our feet took advantage of it. My wife wore size 5 when I met her, 7-1/2 now. I was a bad influence, huh.
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