Nissan Murano 20 Inch Wheels

The 20-inch wheel option on the Nissan Murano is more than just a visual upgrade. It represents a deliberate engineering choice with implications for handling, ride comfort, fuel efficiency, and even tire wear. Understanding these implications requires a closer look at the components involved and the trade-offs inherent in upsizing wheel diameters.

Wheel and Tire Assembly: A Primer

Before diving into the specifics of the Murano's 20-inch wheels, let's establish a foundation. A wheel and tire assembly is a complex system, not just a simple circle of metal and rubber. The wheel itself provides the structural support and mounting point for the tire. The tire, in turn, provides the contact patch with the road, influencing everything from grip to noise vibration and harshness (NVH).

Key parameters to consider include:

Wheel Diameter: The diameter of the wheel's mounting surface, typically measured in inches. In our case, 20 inches.
Wheel Width: The distance between the inner and outer flanges of the wheel, determining the tire's cross-sectional shape.
Offset: The distance between the wheel's mounting surface and its centerline. A positive offset moves the wheel inward, closer to the suspension. A negative offset moves it outward. Incorrect offset can lead to rubbing against the suspension components or fender.
Bolt Pattern: The number and spacing of the lug nuts that secure the wheel to the hub.
Tire Size: Expressed as a series of numbers, such as 235/55R20. Here, 235 represents the tire's section width in millimeters, 55 is the aspect ratio (the ratio of the tire's sidewall height to its section width), R indicates radial construction, and 20 denotes the wheel diameter it's designed for.
Load Index: A numerical code indicating the maximum weight a tire can carry.
Speed Rating: An alphabetical code indicating the maximum speed a tire can sustain.

The Murano's 20-Inch Wheel Specifications

While specific specifications can vary slightly between model years and trim levels, the Nissan Murano's 20-inch wheels generally adhere to the following characteristics:

Diameter: 20 inches (50.8 cm)
Width: Typically ranges from 7.5 to 8.5 inches.
Offset: Designed to maintain proper clearance with the suspension and brake components. The specific offset varies, but it is crucial to use the correct offset to avoid issues.
Bolt Pattern: Typically 5x114.3 mm (5x4.5 inches). This means five lug nuts spaced on a 114.3 mm circle.
Tire Size: Often paired with a 235/55R20 or 255/50R20 tire. The exact size will depend on the wheel width and desired ride characteristics.

Impact on Handling

A larger wheel diameter, like that of the 20-inch wheels on the Murano, can influence handling in several ways. The larger diameter allows for a shorter sidewall on the tire, assuming the overall tire diameter remains relatively consistent to maintain accurate speedometer readings. This shorter sidewall has some effects:

Reduced Sidewall Flex: With a shorter sidewall, the tire flexes less during cornering. This translates to a more direct steering response and improved stability. The vehicle feels more planted and predictable in turns.
Increased Road Feel: The reduced sidewall flex also allows the driver to feel more of the road surface. This can be beneficial for experienced drivers who appreciate a more connected driving experience, but it can also transmit more vibrations and harshness to the cabin.
Potentially Improved Cornering Grip: Depending on the tire compound and tread pattern, a wider tire (often paired with larger wheels) can provide a larger contact patch, leading to increased grip. However, this is heavily dependent on the specific tire model.

However, the benefits aren't without trade-offs.

Impact on Ride Comfort

The shorter sidewall that improves handling can negatively impact ride comfort. The tire sidewall acts as a primary shock absorber, cushioning the vehicle from bumps and imperfections in the road. A shorter sidewall provides less cushioning, resulting in a firmer, less forgiving ride. Passengers may feel bumps and potholes more acutely. This is a significant consideration for a vehicle like the Murano, which is primarily designed for comfort and practicality.

Impact on Fuel Efficiency

Larger wheels, especially those made from heavier materials, can increase the vehicle's unsprung weight. Unsprung weight refers to the weight of components that are not supported by the suspension, such as the wheels, tires, brakes, and axles. Increasing unsprung weight can have several negative consequences for fuel efficiency:

Increased Rolling Resistance: Wider tires, often paired with larger wheels, tend to have higher rolling resistance. This means it takes more energy to rotate the tires, which translates to lower fuel economy.
Increased Inertia: Heavier wheels require more energy to accelerate and decelerate. This increased inertia can reduce fuel efficiency, especially in stop-and-go traffic.

However, modern wheel design and materials are constantly evolving. Many aftermarket wheels, and even some OEM options, utilize lightweight alloys and advanced manufacturing techniques to minimize weight and improve aerodynamics, mitigating the negative impact on fuel efficiency.

Impact on Braking

Larger wheels can provide more space for larger brake rotors and calipers. This allows for improved braking performance due to the increased thermal capacity of the larger rotors and the greater clamping force of the larger calipers. However, the standard Murano 20-inch wheels likely do not significantly impact braking performance compared to the smaller wheel options, unless paired with an upgraded brake system.

Tire Selection and Considerations

The choice of tire is just as important as the wheel itself. When selecting tires for 20-inch wheels on a Murano, consider the following:

Tire Type: All-season tires are a popular choice for their versatility, providing good performance in a variety of conditions. Performance tires offer enhanced grip and handling, but may sacrifice ride comfort and tread life. Winter tires are essential for driving in snow and ice.
Tread Pattern: The tread pattern affects traction, noise levels, and water evacuation. Consider your driving conditions and priorities when choosing a tread pattern.
Tire Compound: The tire compound affects grip, tread wear, and rolling resistance. Softer compounds provide better grip but wear faster.
Load Index and Speed Rating: Ensure that the tires meet or exceed the vehicle's recommended load index and speed rating.

It is critical to maintain the correct tire pressure, which is usually indicated on a sticker on the driver's side doorjamb. Improper tire pressure can lead to uneven tire wear, reduced fuel efficiency, and compromised handling.

Potential Problems and Maintenance

While 20-inch wheels can enhance the Murano's aesthetics, they also require careful maintenance and awareness of potential problems:

Increased Risk of Damage: The shorter sidewalls offer less protection against potholes and curbs. Wheels can be more easily damaged, requiring repair or replacement.
More Noticeable Road Imperfections: As previously mentioned, the ride becomes harsher.
Alignment Sensitivity: Misalignment is magnified on larger wheels and shorter sidewalls, leading to uneven tire wear. Regular alignment checks are essential.
Potential for Rubbing: If the wheels are not properly sized or the offset is incorrect, they may rub against the suspension components or fender liners, especially when turning or going over bumps.

Conclusion

The 20-inch wheels on the Nissan Murano represent a carefully considered design choice. While they offer improved handling and a more aggressive appearance, they also come with trade-offs in ride comfort, fuel efficiency, and potential maintenance costs. Ultimately, the decision to opt for 20-inch wheels depends on individual priorities and driving conditions. Understanding the engineering principles and trade-offs involved allows for a more informed and satisfying ownership experience. Always consult with a qualified mechanic or tire professional to ensure proper fitment and performance.