In order to get my wife riding, I gave up on individual bikes and got an old Peugeot tandem. We've only ridden it a couple times, but my plan seems to be a success. The problem is, we live in a remote area with lots of gravel roads and chip-seal (very rocky) on the paved roads. The crusty old tires didn't last long and after the last rain, sunk in on the muddy back roads. I'm thinking about cyclocross tires. Does anyone have any thoughts? Does anyone know what size wheels they typically had on these (you can't read anything on the tires or rims)? Does anyone know what this bike is worth (I traded an old cow worth about $500 - I told you we're in a remote area ).