Definately not! Cracking on the outside is a sign of weather beating, but when the bike has been garage kept, it may not show those lines or cracks, but the rubber breaks down over time. It can be real dangerous to ride on old tires that have not experienced any real heat or pressure changes in a long time and they will not be as elastic! Remember, the nature of a rubber tire is to produce friction to keep you on the road. That same friction is what heats up the tire and you could experience a sudden blow out without warning with old tires. :crying: