Hi - I have an old frame that I'm trying to build up. It's a Motobecane Super Mirage, most likely from the 70s; it says it's made in France. I'm trying to figure out what size wheels it needs, which I naively thought would be a simple question...

I tried swapping the front wheel from another bike (Mavic CXP22 wheels, supposedly 700c), but the radius is a bit too small, by maybe 1cm; enough that the brakes wouldn't reach the rims.

Did bikes from this time use a different standard for wheel size? Or do I just need to find brakes with a longer reach?