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Storm Storm Norm Duke Clear specs
The Storm Storm Norm Duke Clear is a polyester (plastic) ball with the Cube core. Here are its published specs, how they compare with the other current balls in our table, and what the numbers mean on the lane.
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| Coverstock | Poly Clear |
|---|---|
| Cover type | Polyester |
| Core (weight block) | Cube |
| Core type | Symmetric |
| RG | 2.800 |
| Differential | 0.018 |
| Factory finish | 3500 Grit Polished |
| Flare potential (maker) | Low |
| Maker's category | Ice |
| Color | Clear/Blue |
| Release date (maker) | 04/10/26 |
Numbers as Storm publishes them, checked 21 October 2026. Storm doesn't say which ball weight these numbers are for. Drilling changes how a ball behaves, so a pro shop's layout matters as much as these numbers.
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What the numbers mean
Polyester cover. Polyester (plastic) is the cover used for spare balls and house balls: it grips the lane least, so the ball goes nearly straight. See our plastic spare ball review.
Symmetric core. Storm says symmetric balls have "RG values consistent across all axes" and a smooth, predictable roll.
USBC allows an RG from 2.447 to 2.813 inches and a differential of at most 0.060 inches (Equipment Specifications Manual, March 2026). Our ball spec table lists every current ball we track, and who makes bowling balls covers which company owns Storm.
Balls with similar numbers
Same cover type, closest RG and differential in our table:
- Storm Clear Storm Teal: RG 2.800, differential 0.020
- Motiv Aspire: RG 2.750, differential 0.028
- Storm Ice Storm Black-White-Gold: RG 2.720, differential 0.005
- Roto Grip RG Jester Clear Polyester: RG 2.690, differential 0.006
Sources: Storm product page; Storm, "Inside The Bowling Ball"; Storm, "The Coverstock"; USBC Equipment Specifications Manual.