I don't know. I must be missing a gene or something but I can't see the attraction of junking a perfectly good set of wheels and spending possibly hundreds of dollars for a new wheelset that will get used <shrug> what, a couple or more dozen times, if that? I don't think I am giving bad advice to suggest the o.p. determine the widest tires that will fit in their co-motion, obtain them and call it good. All the tandems in our club run 28mm clinchers. The ride leader messed up one ride and we found ourselves on a stretch of gravel that went on for three miles. It wasn't fun, but we all made it through. Unless I way miss my guess, the o.p. could possibly get 10mm bigger than whatever they have now, and that should be plenty good enough.