345/25R21 tires: size explained
345/25R21 is a Euro-metric tire size. It is about 27.8 in (706 mm) tall, 345 mm wide, and made for a 21-inch wheel.
What 345/25R21 means
A tire size describes the tire's shape and the wheel it fits. It says nothing about load capacity or speed capability, which are printed separately on the sidewall.
- No letterEuro-metric
- With no letter in front of the width, this is a Euro-metric size (also called hard metric). It has the same dimensions as the P-metric version but is built to a different load standard, so its load capacity can differ.
- 345Section width
- The tire's width is 345 millimeters (13.6 in), measured from sidewall to sidewall.
- 25Aspect ratio
- The sidewall height is 25% of the width. For 345 mm that is about 3.4 in (86 mm). A smaller number means a shorter sidewall.
- RRadial construction
- R means radial construction, where the internal cords run across the tire from one edge to the other.
- 21Wheel (rim) diameter
- The tire is made for a wheel 21 inches across. Its overall diameter is larger: about 27.8 in (706 mm).
345/25R21 dimensions
- Section width
- 13.6 in (345 mm)
- Sidewall height
- 3.4 in (86 mm)
- Wheel (rim) diameter
- 21.0 in (533 mm)
- Overall diameter
- 27.8 in (706 mm)
- Circumference
- 87.3 in (2218 mm)
- Revolutions per mile
- 726
These are nominal design dimensions. Real tires vary by brand, tread depth, wheel width, load and pressure.
Which vehicles use 345/25R21?
These vehicles list 345/25R21 among their verified sizes, by trim. Open one to see all of its sizes.
- 2026 Chevrolet Corvette E-Ray(rear)
- 2026 Chevrolet Corvette Z06(rear)
- 2026 Chevrolet Corvette ZR1(rear)
- 2026 Chevrolet Corvette ZR1X(rear)
- 2025 Chevrolet Corvette E-Ray 1LZ(rear)
- 2025 Chevrolet Corvette E-Ray 1LZ w/ ZER Performance Pkg.(rear)
- 2025 Chevrolet Corvette E-Ray 2LZ(rear)
- 2025 Chevrolet Corvette E-Ray 2LZ w/ ZER Performance Pkg.(rear)
- 2025 Chevrolet Corvette E-Ray 3LZ(rear)
- 2025 Chevrolet Corvette E-Ray 3LZ w/ ZER Performance Pkg.(rear)
- 2025 Chevrolet Corvette Z06 1LZ(rear)
- 2025 Chevrolet Corvette Z06 1LZ w/ Z07 Performance Pkg.(rear)
- 2025 Chevrolet Corvette Z06 2LZ(rear)
- 2025 Chevrolet Corvette Z06 2LZ w/ Z07 Performance Pkg.(rear)
- 2025 Chevrolet Corvette Z06 3LZ(rear)
- 2025 Chevrolet Corvette Z06 3LZ w/ Z07 Performance Pkg.(rear)
- 2025 Chevrolet Corvette ZR1(rear)
Shop for 345/25R21 tires
Confirm the size on your tire sidewall or door placard first. These links open each store's own search for 345/25R21; prices and stock are on their sites.
- Search 345/25R21 at Tire Rack
- Search 345/25R21 at Discount Tire
- Search 345/25R21 at SimpleTire
- Search 345/25R21 at Amazon
- Search 345/25R21 at Priority Tire
We may earn a commission if you buy through these links. It doesn't change the price you pay. Read our affiliate disclosure.
Snow chains and tire socks for 345/25R21
Where winter roads call for extra traction, chains and tire socks are two options that fit over your tires. They are made for specific tire sizes, so these links open Amazon searches for 345/25R21. Whether they suit your vehicle depends on its clearance and the local rules.
Paid links to Amazon search results. As an Amazon Associate I earn from qualifying purchases. Read our affiliate disclosure.
Before you buy
- Chains and socks are sold by tire size, so match the size on your sidewall exactly.
- Check your owner's manual first: many newer cars and SUVs limit or prohibit chains, or require low-profile (often called SAE Class S) chains because of tight wheel-well clearance.
- Tire socks are a lighter-duty option; check your state's rules, because some areas only accept chains when chain controls are in effect.
- Put them on the drive wheels (or as your manual says) and follow the maker's speed limit.
Similar sizes
These common sizes have an overall diameter within about 3% of 345/25R21. A common rule of thumb is to keep a replacement size within about 3% of the original overall diameter. Confirm any size change with your vehicle's owner's manual or a tire professional.
| Size | Wheel diameter | Diameter difference | Calculator |
|---|---|---|---|
| 225/60R17 | 17 in (different) | -0.58% | Compare 345/25R21 with 225/60R17 |
| 235/55R18 | 18 in (different) | +1.39% | Compare 345/25R21 with 235/55R18 |
| 225/65R17 | 17 in (different) | +2.61% | Compare 345/25R21 with 225/65R17 |
| 215/65R16 | 16 in (different) | -2.83% | Compare 345/25R21 with 215/65R16 |
Same dimensions, different load standard
P345/25R21 (P-metric) has the same dimensions as 345/25R21, but it is built to a different load standard. Check the load index on the sidewall rather than assuming the two are interchangeable.
Compare 345/25R21 with similar sizes
Side-by-side dimensions and speedometer difference for sizes close to 345/25R21 in overall diameter.
- 225/55R18 vs 345/25R21-0.17% shorter than 345/25R21
- 215/70R16 vs 345/25R21+0.21% taller than 345/25R21
- 285/35R20 vs 345/25R21+0.23% taller than 345/25R21
- 245/45R19 vs 345/25R21-0.40% shorter than 345/25R21
- 315/40R18 vs 345/25R21+0.47% taller than 345/25R21
- 275/40R19 vs 345/25R21-0.47% shorter than 345/25R21
- 225/60R17 vs 345/25R21-0.58% shorter than 345/25R21
- 255/40R20 vs 345/25R21+0.86% taller than 345/25R21
- 295/35R20 vs 345/25R21+1.22% taller than 345/25R21
- 235/40R20 vs 345/25R21-1.40% shorter than 345/25R21
Compare 345/25R21 with another size
See how another size differs in height, width, sidewall and speedometer reading in the tire size calculator.
Compare 345/25R21 with another sizeQuestions about 345/25R21
What does 345/25R21 mean?
345/25R21 describes the shape and size of a tire, not how much it can carry or how fast it can go. 345 is the width in millimeters, 25 is the sidewall height as a percentage of that width (about 86 mm), R is the construction type and 21 is the wheel diameter in inches.
How tall is a 345/25R21 tire?
A 345/25R21 tire has a nominal overall diameter of about 27.8 in (706 mm), with a sidewall about 3.4 in (86 mm) tall. These are nominal design dimensions. Real tires vary by brand, tread depth, wheel width, load and pressure.
How many revolutions per mile does a 345/25R21 tire make?
About 726 revolutions per mile, based on a circumference of 87.3 in (2218 mm). A vehicle's speedometer and odometer are calibrated to the tire size it was built with, so a size with a different overall diameter changes what they read. A common rule of thumb is to keep a replacement size within about 3% of the original overall diameter. Confirm any size change with your vehicle's owner's manual or a tire professional.
Is 345/25R21 the same as P345/25R21?
They have the same dimensions: both are about 27.8 in (706 mm) tall and 345 mm wide. They are built to different load standards, though (Euro-metric and P-metric), so the load a tire can carry can differ. Check the load index on the sidewall, and ask a tire professional or your owner's manual before treating them as interchangeable.
Which sizes have a similar diameter to 345/25R21?
Among the common sizes we list, these are within about 3% of the overall diameter of 345/25R21: 225/60R17 (-0.58%), 235/55R18 (+1.39%), 225/65R17 (+2.61%), and 1 more. Diameter is only one measure. Width, wheel diameter, load capacity and clearance matter too. Confirm any size change with your vehicle's owner's manual or a tire professional.
You might also need
- Digital tire pressure gauge (Amazon search, opens in a new tab)
Check your tire pressure against the number on your door placard.
- Portable tire inflator (Amazon search, opens in a new tab)
Top up a low tire at home without a trip to the gas station.
- Tire tread depth gauge (Amazon search, opens in a new tab)
Measure how much tread is left before you decide to replace.
- Lug wrench or torque wrench (Amazon search, opens in a new tab)
Useful for rotations and tire changes; follow the torque spec in your owner's manual.
Paid links to Amazon search results. As an Amazon Associate I earn from qualifying purchases. Read our affiliate disclosure.