Bulges? Not good at all.
Did you happen to check the manufacture date on the tire?
Usually its molded on the sidewall in a 4-digit pattern of 2-digit year and 2-digit week.
So 1302 is 2nd week of 2013.
A tire is at most, good for 5 to 6 years, even when sitting on the shelf.
Shorter if the tire is exposed to a hot environment, more if the tire is in a cooler environment.
What happens is the plasticizer degrades over time and the tire loses flexibility in the carcass and tread.