Highest differential

Question
I know the limit use to be .80 then it was lowered to .60, I was a little curious to find out what the highest differential ever produced in a bowling ball. I have yet to find an article confirming it.  

Answer
David,
If I'm not mistaken, when they set the parameters for Differential Radius of Gyration they used the max core shape at the time, and basically said no more than this (.060). Between the conception of the rule and its adoption, a few balls exceeded the parameter and were grandfathered in.

You can create stronger differential using a weight hole.

Some current balls utilize a .060 Differential, but be aware of the Intermediate Differential also. Stronger Int. Diff. suggests significant core strength too, and earlier transition.

Thanks for the question.