Husband bought a flat bar road bike from Nashbar. It came with 25c tires. The rims should take tires as wide as 32 or 35 and there is plenty of clearance. He would like to put wider tires on the bike, for comfort. Tire recommendations? Flat are rarely an issue in Minnesota, Michigan and Iowa where he mostly rides. He will be riding some down in Texas this winter, mostly on paved bike paths.