Join Date: Dec 2010
Location: northern Deep South
Bikes: Fuji Touring, Novara Randonee
+1 to checking the seating.
If the tire's seated properly, and if you have a bike rack on your car, hang the bike on the rack and check the wheel for true. Grab a Sharpie or a pencil, steady your hand on the frame (or fork) just where the tire meets the rim, and spin the wheel with your other hand. If the wheel jumps up, down, or from side to side, by more than a couple of millimeters while it's spinning, it needs to be trued. Go ahead and check both wheels while it's up there, although the rear wheel seems to lose true way more often than the front on my bikes.