Bowling Ball Coverstock Types Explained

The coverstock is the outer shell of a bowling ball, the part that touches the lane and the oil. There are four main coverstock types: polyester (plastic), urethane, reactive resin and particle. They differ mainly in how much friction they create, and therefore in how much and when the ball hooks. The core, the surface finish, your speed and rev rate, and the lane conditions all play a part too.

Not sure yet whether you want to throw straight or hook the ball? Start with hook vs straight ball.

Polyester (plastic)

Polyester is the hardest coverstock with the smoothest surface. It absorbs hardly any oil, creates the least friction and rolls the straightest. House balls are usually polyester or basic urethane.

• Spares: a straight line makes corner pins such as the 7 or 10 easier to aim at.
• Straight release: beginners can concentrate on direction, timing and repeatability.

More on the comparison: reactive resin vs polyester bowling balls.

Urethane

Urethane is softer than polyester and grips the lane through surface friction rather than oil absorption. The result is a smoother, more gradual hook than with reactive balls.

• Control: the even curve makes the breakpoint easier to predict.
• Drier lanes: urethane is often used on medium to dry conditions or when a reactive ball reacts too sharply.

Reactive resin

Reactive resin (reactive urethane) contains additives that create microscopic pores. These pores absorb oil, so the ball grips the lane more and hooks more than a urethane ball. Reactive balls come in three main families:

• Solid: the most pores and the strongest oil absorption. Solids grip earlier and suit heavier oil.
• Pearl: additives such as mica reduce the pores. Pearls glide through the front of the lane more easily and react later and more sharply, often on drier lanes.
• Hybrid: combines solid and pearl components, with midlane grip and backend reaction, often on medium oil.

These labels are a starting point; the exact reaction depends on the specific ball.

Particle

Particle coverstocks are reactive shells with microscopic particles, such as glass, ceramic or silica, mixed into the cover. The particles reach through the oil to the lane surface, which is why particle balls are mainly used on heavy oil.

Surface and care

In its ball motion study, USBC found that the most important factors for a ball's path are coverstock properties, including surface roughness, coefficient of friction and oil absorption rate. A rougher surface means more friction, a polished surface lets the ball glide further.

• Wipe oil off the ball after play, especially with reactive and particle balls.
• Follow the manufacturer's instructions for sanding and polishing.
• If the reaction changes noticeably, check the surface.

Step by step: clean your bowling ball after every game and bowling ball surface care.

Which coverstock for beginners?

1. Straight shots and spares: polyester is the usual starting point.
2. Learning to hook: first a good fit and a repeatable release, then an entry-level reactive or a urethane ball.
3. Test on your lanes: judge the ball by how it actually reacts on the lanes you bowl on.
4. A second ball with a purpose: it is useful when it gives you a clearly different reaction, for example a polyester ball for spares next to a reactive ball.

A pro shop can help you choose. How to approach the first purchase is explained in how to choose your first bowling ball, and the role of the core in symmetric and asymmetric bowling ball cores.

Coverstock types at a glance