Originally Posted by
RiddleOfSteel
You sound exactly like me!

I have a 610 (1982) that won't get to 36mm let alone 38mm tires, but I think it'd be great to, and I ran those exact same tires (briefly) in the same size. The brakes have plenty of vertical clearance for 38s due to the caliper mounting height, and the fork is fine as well. If I did dimpling, I'd probably have other things done to it. Lots of touch-up paint applied, plus a small dent in the TT, and damaged decals (photographs well, though). It's actually a pretty light frameset for a longer sport tourer and it did well when I built it up with modern components. The Strada Biancas felt amazing at 60/70 psi, but rolled too slowly. +5 psi for both and that was too much. Weird. Oh well, time for bigger tires via dimpling???
A bit of a silly build, but good nonetheless. Half built with 27" wheels sorta like it would have been, but honestly it feels criminal given how heavy those wheels are and how light the frame is. I'll probably port it over to another (lower level Trek) frame to sell and leave the 610 for more musings.

I can't say the Strada Biancas roll too slowly, they are nicer all around than my previous favorite, plus I don't need another build project at the moment. At some point I tried a Pasela pair, but I think I gave them to a bud. If I can fit 38s after looking at everything, I'll either go for Swifts, ProTites, or ReneHerse.
You can make decent and light 630 wheels, and tire for tire the 630's have radius only 4 mm bigger than the 700c (aka 622's). If you're careful about choosing hooked (the modern kind) aluminum 27 x 1 1/4 rims and use a slim spoke, like a butted 2.0/1.7/2.0 Wheelsmith, you can make some strides. If you want to go hookless you have more variety in tires, but probably you should find what rims you can get and what tires you can get - obviously the types need to match. On my Witcomb build I swapped spokes over from 1974 steel French rims (a lot like the Rigidas used on the Peugeot UO-8s) to nearly equally old Ukai not-hooked rims with the original spokes - zinc-clad 1.8/1.6/1.8. Those are each at least 100 grams lighter than the steel rims I took off, and luckily trued up pretty nicely. The only complicated part was to measure the old rims and calculate ERD and then do the same for the "new rims." The two ERDs were the same (close enough) so I just swapped over spoke by spoke.