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Tire Size Guide

325/40R21 Tires

Compare 2 available models across 1 categories, then confirm fitment for your vehicle.

Our Top Pick in 325/40R21
Continental ContiSportContact 5P
Ultra High Performance SummerPerformance

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.
79Spec score (est.)
Full analysis
2 models

Best Ultra High Performance Summer Tires in 325/40R21

All Ultra High Performance Summer tires
Continental ContiSportContact 5PPerformance

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.

If you prioritize high-speed capability, the Michelin Pilot Sport 4S with its higher speed rating might be a better choice.

Treadwear 280Traction AA
Spec score79estimated
Details
Michelin Pilot Sport 4 SUVPerformance

The Michelin Pilot Sport 4 SUV is tailored for drivers who prioritize dry grip and handling precision in their summer tire choice.

  • 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).

20,000 mi warrantyTreadwear 220Traction A
Spec score59estimated
Details
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Popular Brands in 325/40R21

Continental · 1Michelin · 1
Size decoded

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.

130 mm

Sidewall height

31.2"

Overall diameter

98.1"

Circumference

646

Revs per mile

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.

Before you buy

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

Buying Guide

Speed Rating Chart

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

Read guide

Buying Guide

UTQG Ratings Explained

Understand treadwear, traction, and temperature grades and when UTQG comparisons are useful.

Read guide

Buying Guide

When to Replace Tires

Know the real tread-depth, age, and wear-pattern signs that mean your tires are ready to be replaced.

Read 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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