The core mass in today's bowling balls are heavier & larger which puts more pressure on the less dense
cover of the ball.If the ball stays in one place without being moved the mass & weight put pressure
on the cover thus weakening it .The ball must be shifted at least 1/4 rotation at least one time per
month.I had this problem for years with every manufacturer,the balls were always in rooms in my house
the had perfect climate control.I could not figure out why this keep happening.I finally called and
spoke to two ball companies,booth companies Storm & Ebonite got back to me within a week with this same information.Since they told me this 5 years ago I have not had one ball crack on me.