Finding 20" Schwalbe Marathons in Boston [URGENT]
We're in the middle of a bike ride, taking a few days in Boston to do a scientific conference, and have realized that our back tire on our Bike Friday tandem is bulging. Whoops. Time to replace it. The problem is, I'm having trouble finding 20" Schwalbe Marathons in Boston. I'd like to replace the existing 20x1.5 with another 20x1.5, but could consider another size if necessary.
Does anyone know a bike store in Boston that carries this kind of stuff? All I can find with Google is online stores, and worry about their ability to hit a moving target. We're leaving on Thursday, so don't feel that any shipping service would be fast enough, without paying oodles of money for next-day air.
P.S. It could actually be any store close to I-95 between Boston and Bangor, ME. We'll be driving that part of the trip.