Travel enough and you're going to get a flat. Assuming you can effect a repair by the side of the road, the next question is, er, what's next? Depends. If the tire is close to worn out, you've just given yourself the perfect reason to buy a new one. Find the nearest motorcycle dealer or independent shop, be especially nice to the service people and you'll be out of there in a couple of hours. Don't worry about matching tires front to rear, but stick to the original size and category of tire; that is, don't substitute a touring-oriented bias-ply for a race-spec radial. That said, many riders successfully run two different tire brands, and even more mix and match models from the same manufacturer --such as a soft sport tire for the front and a more durable sport-touring tire for the rear.