What does 315/30R18 mean?

In 315/30R18, 315 is the tread width in millimeters (about 12.4 inches). 30 is the aspect ratio: the sidewall height is 30% of the width, or about 95 mm (3.7 inches). "R" means radial construction, which nearly all passenger and light truck tires use today. 18 is the wheel diameter in inches. Put together, the tire stands about 25.4 inches tall when new.

What do the load index and speed rating after the size mean?

The code after the size, such as 102H, tells you how much weight each tire can carry and how fast it is rated to go. The number is the load index (102 means 1,874 lbs per tire) and the letter is the speed rating (H means up to 130 mph). Your replacement tires should meet or exceed the load index and speed rating on the placard in your driver’s door jamb.

What is the difference between SL (Standard Load) and XL (Extra Load) tires?

An XL tire is built to carry more weight than an SL tire of the same size, and it reaches that higher capacity at a higher inflation pressure. Heavier crossovers, trucks, and many electric vehicles come with XL tires from the factory because of their weight. If your vehicle’s placard or original tires call for XL in 315/30R18, replace them with XL. Putting XL tires on a vehicle that only needs SL is fine, though the ride can be slightly firmer.

Can I use a different size instead of 315/30R18?

Often, yes, within limits. A common guideline is to keep the new tire’s overall diameter within about 3% of the original. For 315/30R18, which is about 25.4 inches tall, that means roughly 24.7 to 26.2 inches. A taller tire makes your speedometer read low: with a tire 3% larger, it shows about 58 mph when you’re actually going 60. Also check that the new size fits your wheel width, clears the suspension and fenders at full steering lock, and meets your vehicle’s load rating. When in doubt, ask a tire installer before switching.

Why do prices for the same 315/30R18 tire vary across retailers?

Each retailer sets its own prices and runs its own promotions. The total you pay also depends on shipping costs, installation and disposal fees, road hazard coverage, and manufacturer mail-in rebates, which can be worth $50 to $100 or more on a set of four. Stock and pricing can also vary by region. Compare the full cost at checkout, not only the tire price.

Do the prices shown include installation or shipping?

The prices we show are the per-tire prices listed by each retailer. Shipping, installation, taxes, and fees depend on the retailer and your location, and are shown at the retailer’s checkout.

Should I replace all four tires at once?

Replacing all four keeps handling and braking even. If you replace only two, most tire makers recommend putting the new pair on the rear axle to help prevent oversteer on wet roads. All-wheel-drive vehicles often need all four tires to have closely matched tread depth to protect the drivetrain, so check your owner’s manual before replacing only some.

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Gladiator X COMP H/P

315/30R18 99Y

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The Gladiator X-Comp H/P is a 200-treadwear summer ultra-high-performance tire for performance cars in warm weather, with a race-inspired compound and an asymme…Full details

$804.24

for 4 tires

$201.06 per tire

at Walmart

Walmart★ Best Price

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In StockLoad 99Speed Y

Save $82.32 vs next best

$804.24

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$201.06 per tire

was $920.04

315/30R18 Tires — Compare Prices

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Gladiator X COMP H/P

Kenda VEZDA SUMMER MP+ (KR20AX)

Kenda Vezda UHP A/S (KR400)

BFGoodrich G-Force Rival S 1.5

Yokohama Advan A052

BFGoodrich G-Force Rival S

Continental ExtremeContact Force

Falken Azenis RT-615K+

Toyo Proxes R888R

BFGoodrich G-Force Rival

Bridgestone POTENZA RE-71RZ

Nankang Sportnex CR-S

Toyo Proxes Sport

Falken Azenis RT660

Vitour Tempesta P1 P-01R

Nitto NT01

Pirelli Trofeo R

Michelin Pilot Sport PS2

Toyo Proxes R

Nankang AR-1

315/30R18 Tires — Compare Prices

Find the right tires. Clearly.

All Tires(23)

Gladiator X COMP H/P

Kenda VEZDA SUMMER MP+ (KR20AX)

Kenda Vezda UHP A/S (KR400)

BFGoodrich G-Force Rival S 1.5

Yokohama Advan A052

BFGoodrich G-Force Rival S

Continental ExtremeContact Force

Falken Azenis RT-615K+

Toyo Proxes R888R

BFGoodrich G-Force Rival

Bridgestone POTENZA RE-71RZ

Nankang Sportnex CR-S

Toyo Proxes Sport

Falken Azenis RT660

Vitour Tempesta P1 P-01R

Nitto NT01

Pirelli Trofeo R

Michelin Pilot Sport PS2

Toyo Proxes R

Nankang AR-1

315/30R18 tire FAQ

What does 315/30R18 mean?

What do the load index and speed rating after the size mean?

What is the difference between SL (Standard Load) and XL (Extra Load) tires?

Can I use a different size instead of 315/30R18?

Why do prices for the same 315/30R18 tire vary across retailers?

Do the prices shown include installation or shipping?

Should I replace all four tires at once?