Also, look closely at the rubber on the sidewalls. A riding partner is using a bike she borrowed from a friend of a friend. I brought it home to do a tune-up and swap cassettes. I looked at the sidewall of the front tire and could see hairline cracks in the rubber. Someone once referred to them as "Dry rot cracks". I was going to swap tires so that the worse tire was one the rear...and it already was...the rear tire was worse. I told her she had to go buy new tires.