Originally Posted by
truthseeker14
Ha ha. Actually I bought a vintage bike that took 27" tires on purpose. I wanted to go loaded touring on my Soma Doublecross Disk but it only had 24 spokes per wheel and I realized that may not be enough for touring, and I figured for the price of a new wheel set, I could buy a vintage touring bike that had plenty of spokes. And this is what I did. (Bridgestone T-700 from 1985, 40 spokes rear, 36 front). Plus I always loved the classic look of bikes from the 70s and 80s. I could always put fatter 700c tires on my Soma for commuting but the rim is pretty narrow (18 mm, I think). I've heard different opinions on putting fatter tires on narrow rims.
There is no inherent disadvantage of 27" wheels apart from lack of tire choices and availability. Just make sure you have a spare tire packed with you on tour because you might not like the selection available at any given shop or town... you can likely find a 27" tire at any shop or even W*lmart or a hardware store, but likely not of the quality you'd want for reliable long distance riding. You've probably come to this conclusion already.
As for the mismatch of narrow rims with wider tires, there are drawbacks but it's 100% fine to do. The main problem is that the profile of the tire will be an exaggerated 'omega' shape - the sidewalls of the tire will stick out much further than the sides of the rim, and this profile may allow pinch flats more easily (esp. if the tire is underinflated), it might have a slightly 'squirmier' feel compared to a better match of tire and rim widths, and at higher speed it will have higher aerodynamic drag than a wheel/tire with less difference in width. It's totally fine to ride, though, if you keep these things in mind.