When I built my loaded touring frame in 1981 I deliberately designed it to use the then-fading 27" wheel size so I could find replace tires or even wheels easily, even at the only place that in dozens of miles that stood a chance of having bike stuff -- like a hardware store in Coldwell ON. You could only find 700C tires and rims at upscale bike shops in fairly large towns and I preferred touring in near-wilderness areas.