Hey a_j316,
The Rule is designed for med/heavy conditions so that's why it worked better for you on that type of condition. If we could have "one" ball that would work on med/heavy and then med/dry, that would be ideal but it doesn't work that way.
Here's a brief explanation, a bowling ball creates a certain amount of friction on the lane as it rolls. Let's compare this to a football player's cleats from 1 inch, 3/4, 1/2, down to nubs and gym shoes. His 1 inch cleat works fine in mud to create a required amount of friction but he can't use this on astroturf, correct? He'll have to switch to nubs or maybe gym shoes for that condition, same thing applies in bowling. That's why we have so many bowling balls with different coverstocks to adhere to a particular lane condition to create the desired amount of friction.
Just as Excaliber explained, it's more important for you to decide which condition you will want to use this ball on. If you polish it, it will probably work better on the med/dry condition but now it may not work as well on your med/heavy condition. Hope this helps explain some..
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Rick Leong
Ten Pins Pro Shop
Track Intl. - Amateur/Pro Shop Staff
Vise Inserts Staff