The last time I rode a road bike, I kept using up rims hitting the unavoidable urban potholes, crevasses, debris, etc. So I switched over to an mtb and that was much better. Now I'm moving back to a vintage road bike...but I'd MUCH rather not go back to consuming rims! I'm assuming there are lightweight rims that are also sturdy, and that you guys know where to find them

27" are not that easy at present, 700c which is about 4mm smaller in radius has a much more wide range of tires, and rims. I would go with 700c if you can and use a larger section tire, the bigger the air chanber the harder to "bottom out".

But then there is always 650B,,, kind of between 26" mtb size and 700c, typical cross section is 1.5" at the tire. Probably need a frame specific for them, Rivendell had a bike that used that size, many French touring bikes used the same size way back too, made sense for secondary roads (dirt) too.

Araya, Ukai, Weinmann and Nisi made some decent 27" rims. Light is kind of relative though.

If you've got the necessary reach with your brake pads, you're better off going the 700C route for all the reasons stated by Repechage. However, if 27" is your only option, I'd suggest the Sun CR-18, which is still made in a 27" version. I.m not sute about the weight, but it is aluminum and of box-section/double wall construction for extra durability. About a month ago, I installed one for a 300 lb riding who flat spotting his normal U-section Arayas. So far, there has been no reported problems.

Thanks, all, for the recommends. I think I'll do some measurements, see whether 700s are an option. Maybe with some xlong-reach calipers.

I've heard good things about the Sun rims as well

+1 on the Sun Cr18 rims. I just did a converison where I switched from 27" to 700cc and am using the Sun rims and 32mm Schwalbe Marathon tires for a vintage, road style commuter bike. Very happy with the set up. Also going to 700cc will allow you to run studded tires if winter riding is a part of your plans. There are no availble 27" studded tires unless you manke them yourself. I can run the 35mm Nokian studded tires w/ full SKS fenders. The older bikes have much more flexibilty with regard to tire clearance.
Good luck!

On many bikes originally set up for 27" wheels, you can convert down to 700c just by using a 47-57 reach caliper with the pads set down near the bottom of the range. This used to be called normal reach but today is called long reach. Much better to just measure to remove the ambiguity.

If the frame has studs for cantilevers, you may or may not be able to convert to 700c. If the studs are too high for the new, lower rim height, you might be inviting the brake pads to dive under the rim due to the increased angle. Also, some cantis allow for more or less verticle adjustment.

If you need to stick with 27", it is hard to know which current 27" rim to suggest. If you are commuting or touring, the Sun CR-18s and Velocity Twin Hollow both have good reputations (but I've not used either).

Hope this helps.

Another option for increased brake reach, if you need it, is centerpull road brakes instead of sidepull calipers. If you need a lot of reach, the centerpulls are hard to beat on a road bike. The Dia-Compes and Weinmanns can be found pretty cheap on ebay, sometimes NOS-