I'm a fan of these vintage touring bikes.I tend to run the max tire size I can fit.On this Passage I'm currently running Continental Contact Speed tires in a folding 700x42.They measure pretty close to stated size on Velocity Dyad rims.I just checked with a caliper.My experience in the past with Continental's also was that they were typically under the stated size.No problem on the fork as there's plenty of clearance there.The rear tire is really too tight and and I was getting some rub on the drive side while cranking with 60 psi.I deflated to about 45 and it was clearing without rubbing but still a very tight fit.If the wheel was out of true (which it's not) it would definitely be a no go.I like this bike enough and the tires I plan on having my local builder dimple the stays to allow adequate clearance.YMMV.I'm now fiddling around with a recently purchased 84 Voyageur and 650b wheels. Challenging!