American Roadstar Sport AS 225/50R18

Looking for a 225/50R18 tire? The American Roadstar Sport AS is available now at ThreePiece.us with free shipping on every order and Affirm financing at checkout.

What 225/50R18 means

In the size 225/50R18, 225 is the section width in millimeters (8.86 in), 50 is the aspect ratio — the sidewall stands 50% as tall as the tire is wide, or 112.5 mm (4.43 in) — R denotes radial construction, and 18 is the wheel diameter in inches. That works out to an overall diameter of about 26.86 inches, turning roughly 751 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 18 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 99 — a maximum load of 1,709 lbs per tire. The speed symbol W corresponds to a maximum sustained speed of 168 mph.

Specifications

Frequently asked questions

What are the treadwear and warranty ratings on the American Roadstar Sport AS?

This tire carries a treadwear grade of 500, traction grade A, temperature grade A under UTQG.

Will 225/50R18 tires fit my vehicle?

Check the size molded into your current tire's sidewall or the tire placard inside the driver's door jamb — if it reads 225/50R18, this tire matches your vehicle's fitment. If you're changing sizes, compare overall diameter to keep your speedometer and clearances right. See every 225/50R18 tire in stock to compare options.

What does 99W mean on the American Roadstar Sport AS?

99W breaks down as load index 99 — rated for 1,709 lbs per tire — with a W speed rating, good for a maximum sustained 168 mph.

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