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355/25R21 Tire Size
All You Need to Know About 355/25R21 Tires
355/25R21 tires are an ultra-wide, ultra-low-profile performance size designed primarily for rear-axle use on high-powered supercars and exotic vehicles. This size prioritizes maximum traction, high-speed stability, and aggressive stance over ride comfort or durability. With a very short sidewall and an extremely wide contact patch, 355/25R21 tires are engineered to manage extreme torque and acceleration forces. Due to the 355/25R21 massive width (14 inches), this tire is almost exclusively a rear fitment. It is paired with narrower front tires (such as 255 or 265) to maintain steering agility while providing the rear-end "meat" needed to deliver 700+ horsepower.
What Are the Dimensions of a 355/25R21 Tire in Inches?
A 355/25R21 tire has a section width of 13.98 inches (≈ 14.0") and a sidewall height of 3.49 inches (≈ 3.5"). The overall diameter of a 355/25R21 tire is 27.99 inches (≈ 28.0"), and the circumference is approximately 87.93 inches (≈ 87.9"). The recommended rim width range for the 355/25R21 size is typically 12.5 to 13.5 inches, depending on manufacturer specifications. In inches, the 355/25R21 tire size can be represented as 28.0" × 14.0" R21.
How tall and wide are 355/25R21 tires?
A 355/25R21 tire is approximately 27.99" (710.90mm) tall and 13.98 inches (355 mm) wide, making it one of the widest road-legal tires available for 21-inch wheels. The extremely short sidewall leaves little margin for impact absorption, so wheel protection and road conditions are critical considerations.
355/25R21 Tire Dimensions from mm in Inches
Tire Specification | Measurement (mm) | Measurement (inches) |
Section Width | 355 mm | 13.98" (≈ 14.0") |
Sidewall Height | 88.75 mm | 3.49" (≈ 3.5") |
Overall Diameter | 710.90 mm | 27.99" (≈ 28.0") |
Circumference | 2233.36 mm | 87.93" (≈ 87.9") |
Radius | 355.45 mm | 13.99" (≈ 14.0") |
Rim Diameter | 533.40 mm | 21.0" |
Recommended Rim Width | — | 12.5–13.5" |
What Cars Does a 355/25R21 Tire Size Fit?
The 355/25R21 size is almost exclusively used as a rear tire in factory or OEM-style staggered performance setups. It is intended for vehicles with very high rear-axle torque output and wide rear wheel housings. Important: 355/25R21 size is rear-axle only, not interchangeable, and not suitable for front use. Wheel width, offset, and suspension geometry must exactly match manufacturer specifications. The table below shows the most common car fits:
Vehicle Model | Variant / Generation | Axle Position | Fitment Notes |
Lamborghini Aventador | LP770-4 SVJ | Rear | Factory rear size on 21-inch wheels, engineered to handle extreme V12 torque and aggressive acceleration loads. |
Lamborghini Aventador | LP780-4 Ultimae | Rear | OEM staggered setup using ultra-wide rear tires to maximize traction and high-speed stability. |
Bugatti Chiron / Divo / Centodieci | Various | Rear (model-specific) | Select Bugatti models list 355-section rear tires on 21-inch wheels, depending on variant and market specification. |
Driving Characteristics of 355/25R21 Tires
355/25R21 tires deliver exceptional straight-line and corner-exit traction, particularly under hard acceleration. The massive tread width allows high-horsepower vehicles to apply power efficiently, while the low-profile sidewall improves steering response and lateral stability at high speeds.
Trade-offs include:
- Very firm ride quality
- High sensitivity to potholes and road imperfections
- Increased risk of wheel and sidewall damage
- Shorter tread life compared to narrower performance sizes (5,000-8,000 miles, typically)
This size is designed for maximum performance, not daily comfort.
355/25R21 Load Index and Speed Rating Considerations
Most 355/25R21 tires are produced with very high load indices (typical service description: 107Y XL), Y and (Y) -speed ratings, suitable for sustained high-speed operation. Always confirm that the load index meets or exceeds the vehicle manufacturer’s rear-axle requirement, as these vehicles place extreme stress on rear tires during acceleration and cornering.
Best Tires for 355/25R21
Because the 355/25R21 is such an extreme size, manufacturers often only produce it in small batches or as "Marked" tires (OE) for specific hypercars. Here are the top fitments:
Key Takeaways
- 355/25R21 is an extreme, rear-only performance tire size
- Commonly used on V12 and hypercar-level platforms
- Requires very wide wheels (12.5–13.5") and precise alignment
- Prioritizes grip and stability over comfort and longevity
- Limited tire availability due to its specialized application
All You Need to Know About 355/25R21 Tires
355/25R21 tires are an ultra-wide, ultra-low-profile performance size designed primarily for rear-axle use on high-powered supercars and exotic vehicles. This size prioritizes maximum traction, high-speed stability, and aggressive stance over ride comfort or durability. With a very short sidewall and an extremely wide contact patch, 355/25R21 tires are engineered to manage extreme torque and acceleration forces. Due to the 355/25R21 massive width (14 inches), this tire is almost exclusively a rear fitment. It is paired with narrower front tires (such as 255 or 265) to maintain steering agility while providing the rear-end "meat" needed to deliver 700+ horsepower.
What Are the Dimensions of a 355/25R21 Tire in Inches?
A 355/25R21 tire has a section width of 13.98 inches (≈ 14.0") and a sidewall height of 3.49 inches (≈ 3.5"). The overall diameter of a 355/25R21 tire is 27.99 inches (≈ 28.0"), and the circumference is approximately 87.93 inches (≈ 87.9"). The recommended rim width range for the 355/25R21 size is typically 12.5 to 13.5 inches, depending on manufacturer specifications. In inches, the 355/25R21 tire size can be represented as 28.0" × 14.0" R21.
How tall and wide are 355/25R21 tires?
A 355/25R21 tire is approximately 27.99" (710.90mm) tall and 13.98 inches (355 mm) wide, making it one of the widest road-legal tires available for 21-inch wheels. The extremely short sidewall leaves little margin for impact absorption, so wheel protection and road conditions are critical considerations.
355/25R21 Tire Dimensions from mm in Inches
Tire Specification | Measurement (mm) | Measurement (inches) |
Section Width | 355 mm | 13.98" (≈ 14.0") |
Sidewall Height | 88.75 mm | 3.49" (≈ 3.5") |
Overall Diameter | 710.90 mm | 27.99" (≈ 28.0") |
Circumference | 2233.36 mm | 87.93" (≈ 87.9") |
Radius | 355.45 mm | 13.99" (≈ 14.0") |
Rim Diameter | 533.40 mm | 21.0" |
Recommended Rim Width | — | 12.5–13.5" |
What Cars Does a 355/25R21 Tire Size Fit?
The 355/25R21 size is almost exclusively used as a rear tire in factory or OEM-style staggered performance setups. It is intended for vehicles with very high rear-axle torque output and wide rear wheel housings. Important: 355/25R21 size is rear-axle only, not interchangeable, and not suitable for front use. Wheel width, offset, and suspension geometry must exactly match manufacturer specifications. The table below shows the most common car fits:
Vehicle Model | Variant / Generation | Axle Position | Fitment Notes |
Lamborghini Aventador | LP770-4 SVJ | Rear | Factory rear size on 21-inch wheels, engineered to handle extreme V12 torque and aggressive acceleration loads. |
Lamborghini Aventador | LP780-4 Ultimae | Rear | OEM staggered setup using ultra-wide rear tires to maximize traction and high-speed stability. |
Bugatti Chiron / Divo / Centodieci | Various | Rear (model-specific) | Select Bugatti models list 355-section rear tires on 21-inch wheels, depending on variant and market specification. |
Driving Characteristics of 355/25R21 Tires
355/25R21 tires deliver exceptional straight-line and corner-exit traction, particularly under hard acceleration. The massive tread width allows high-horsepower vehicles to apply power efficiently, while the low-profile sidewall improves steering response and lateral stability at high speeds.
Trade-offs include:
- Very firm ride quality
- High sensitivity to potholes and road imperfections
- Increased risk of wheel and sidewall damage
- Shorter tread life compared to narrower performance sizes (5,000-8,000 miles, typically)
This size is designed for maximum performance, not daily comfort.
355/25R21 Load Index and Speed Rating Considerations
Most 355/25R21 tires are produced with very high load indices (typical service description: 107Y XL), Y and (Y) -speed ratings, suitable for sustained high-speed operation. Always confirm that the load index meets or exceeds the vehicle manufacturer’s rear-axle requirement, as these vehicles place extreme stress on rear tires during acceleration and cornering.
Best Tires for 355/25R21
Because the 355/25R21 is such an extreme size, manufacturers often only produce it in small batches or as "Marked" tires (OE) for specific hypercars. Here are the top fitments:
Key Takeaways
- 355/25R21 is an extreme, rear-only performance tire size
- Commonly used on V12 and hypercar-level platforms
- Requires very wide wheels (12.5–13.5") and precise alignment
- Prioritizes grip and stability over comfort and longevity
- Limited tire availability due to its specialized application
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