Pirelli PIR PZero 285/40ZR21XL

The Pirelli PZero in 285/40R21 ships free from ThreePiece.us, with Affirm financing available at checkout and fast delivery from a nationwide warehouse network.

What 285/40R21 means

In the size 285/40R21, 285 is the section width in millimeters (11.22 in), 40 is the aspect ratio — the sidewall stands 40% as tall as the tire is wide, or 114.0 mm (4.49 in) — R denotes radial construction, and 21 is the wheel diameter in inches. That works out to an overall diameter of about 29.98 inches, turning roughly 673 revolutions per mile. Overall diameter is what matters for speedometer accuracy and clearance when you change sizes, so compare it — not just the width — against your current tire.

The manufacturer lists the overall diameter of this specific tire as 21 inches — when clearance is tight, go by the published figure rather than the nominal size math.

The service description on this tire decodes to a load index of 109 — a maximum load of 2,271 lbs per tire. The speed symbol Y corresponds to a maximum sustained speed of 186 mph.

Specifications

Frequently asked questions

What does 109Y mean on the Pirelli PZero?

109Y breaks down as load index 109 — rated for 2,271 lbs per tire — with a Y speed rating, good for a maximum sustained 186 mph.

What kind of tire is the Pirelli PZero?

The Pirelli PZero in 285/40R21 is a high performance tire.

What are the treadwear and warranty ratings on the Pirelli PZero?

This tire carries a treadwear grade of 220, traction grade AA, temperature grade A under UTQG.

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