Originally Posted by
repechage
good tires.(well as good as 27" as I can find.)
Not interested in moving the canti posts.
Have you tried 700c wheels? Often it works even though the posts were intended for 27" You might have to put some other brake (not Mafac), something with some up/down adjustability. Or just try Mafac Criterium, the shorter-armed version of the Tandem canti -- their arms from the pivot up to the pad attachment point are 2 mm shorter than Tandem, which might be enough to make the post height work on 700c rims. Criterium brakes can still be plenty strong, especially with modern rubber. And then a whole world of better tire choices opens up. Plus you have more room to use fatter tires, especially nice on a tandem.
Apologies if you tried it already and it's a no-go.