Tire Scouter

325/40R21 tires

Compare 2 models made in this size across 1 category, ranked by spec score, then confirm fitment for your vehicle.

Spec scores are estimates from five manufacturer specs, not road tests. How we score

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Our top pick in 325/40R21

Continental ContiSportContact 5P

  • Ultra high performance summer

Best for performance enthusiasts.

The ContiSportContact 5P is a solid choice for drivers who value high performance in both dry and wet conditions.

  • Dry grip rating of 9, which is above the category average of 8.7, making it a strong performer for spirited driving.
  • Wet grip also scores a 9, significantly higher than the category average of 7.6, providing confidence in rainy conditions.
  • Handling score of 9 ensures precise steering and responsiveness, ideal for performance enthusiasts.
Full analysis

The highest spec score among ultra high performance summer tires in this size that we have analysis for, the most common category for 325/40R21.

79Strong
None listed
280
AA
Y · 186 mph

Every scale below runs from the lowest to the highest spec score among the 2 scored tires in 325/40R21 (59 to 79).

Best ultra high performance summer tires in 325/40R21

2 models, highest spec score first.

All ultra high performance summer tires

  1. Continental ContiSportContact 5P

    Best for performance enthusiasts.

    79StrongFrom 4 of 5 specs
    Warranty
    None listed
    Treadwear
    280
    Traction
    AA
    Speed rating
    Y · 186 mph
    • Dry grip rating of 9, which is above the category average of 8.7, making it a strong performer for spirited driving.
    • Wet grip also scores a 9, significantly higher than the category average of 7.6, providing confidence in rainy conditions.
    • If you prioritize high-speed capability, the Michelin Pilot Sport 4S with its higher speed rating might be a better choice.

  2. Michelin Pilot Sport 4 SUV

    Best for performance SUV owners.

    59Fair
    Warranty
    20k mi
    Treadwear
    220
    Traction
    A
    Speed rating
    W · 168 mph
    • Dry grip score of 9 surpasses the category average of 8.7, making it a strong choice for spirited driving.
    • Handling rating of 9 aligns with the dry grip, providing precise control and responsiveness.
    • Lower wet grip performance compared to category benchmarks and competitors like the Pirelli P Zero (PZ4).

Popular brands in 325/40R21

The number beside each brand is how many of its models come in this size.

What 325/40R21 means

325/40R21 designates a tire 325 mm (12.8") wide with a sidewall 40% as tall as it is wide — about 130 mm (5.1") — mounted on a 21-inch wheel. That works out to an overall diameter of roughly 31.2", a circumference of about 98.1", and approximately 646 revolutions per mile. Exact figures vary slightly by manufacturer and tread design.

Of the 2 325/40R21 tire models we track, the most common category is ultra high performance summer (2 models) — a good indicator of the kind of vehicles and driving this size is designed for.

Sidewall height
130 mm
Overall diameter
31.2 in
Circumference
98.1 in
Revs per mile
646

Frequently asked questions

What does 325/40R21 mean?

325/40R21 breaks down as follows: 325mm is the tire's section width (the widest point), 40 is the aspect ratio (sidewall height as a percentage of width), R means radial construction, and 21 is the wheel diameter in inches.

What vehicles use 325/40R21 tires?

325/40R21 is a standard tire size found on many trucks, SUVs, and crossovers. Use our vehicle search to confirm your exact fitment.

How tall is a 325/40R21 tire?

A 325/40R21 tire has a sidewall height of about 130 mm (5.1") and an overall diameter of roughly 31.2", turning approximately 646 revolutions per mile. Actual dimensions vary slightly by manufacturer and model, so confirm against your vehicle's placard before changing sizes.

325/40R21 research guides

Summer vs all-season tires

Where summer tires lose grip, the cold-cracking risk, and what all-season tires trade for their range.

Read the guide

Speed rating chart

A practical chart for common tire speed ratings and what they mean for everyday driving.

Read the guide

Changing tire size

Plus-sizing and alternate sizes: diameter limits, load and speed ratings, and speedometer error.

Read the guide

Confirm 325/40R21 fits your vehicle

Wheel size can vary by trim and option package. Enter your year, make, model, and trim to verify fitment before you order.

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