What does 315/40R21 mean?

In 315/40R21, 315 is the tread width in millimeters (about 12.4 inches). 40 is the aspect ratio: the sidewall height is 40% of the width, or about 126 mm (5.0 inches). "R" means radial construction, which nearly all passenger and light truck tires use today. 21 is the wheel diameter in inches. Put together, the tire stands about 30.9 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 315/40R21, 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 315/40R21?

Often, yes, within limits. A common guideline is to keep the new tire’s overall diameter within about 3% of the original. For 315/40R21, which is about 30.9 inches tall, that means roughly 30.0 to 31.8 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 315/40R21 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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Lionhart LH-Five

315/40R21 111Y

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UHP All Season

4.9(142)

The Lionhart LH-Five is a UHP all-season for performance vehicles from Lionhart, a brand under Turbo Wholesale Tire (a Los Angeles-based wholesaler founded 2013…Full details

$616.28

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$154.07 per tire

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In StockLoad 111Speed Y

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$616.28

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315/40R21 Tires — Compare Prices

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315/40R21 Tires — Compare Prices

Find the right tires. Clearly.

All Tires(50)

Lionhart LH-Five

Delinte DST 2

Lexani LX-Twenty

Summit Trail Climber SUV2

Ironhead Reflex SUV UVD01

BlackHawk Agility SUV

Atlas Force UHP

Gripmax SureGrip Pro Sport

Arroyo Grand Sport A/S

Rovelo Instinct SUV

American Roadstar Sport AS

Advanta HPZ-02

Yokohama ADVAN Sport V107E

Accelera Iota

Pirelli P ZERO (PZ4)

Nexen N Fera Sport

Kumho Crugen GT Pro

Kumho Crugen GT Pro EV Ready

Pirelli P ZERO

Continental CrossContact LXSport

315/40R21 tire FAQ

What does 315/40R21 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 315/40R21?

Why do prices for the same 315/40R21 tire vary across retailers?

Do the prices shown include installation or shipping?

Should I replace all four tires at once?