Should you replace all 4 tires on a Subaru?

Yes. On most Subaru models equipped with symmetrical all-wheel drive, replacing all four tires at once is typically the safest and most reliable approach when one tire wears out or when you’re upgrading tires, to maintain equal circumference and minimize drivetrain wear. If you can’t replace all four right away, you should still aim to match size and model and consider placing new tires on the rear axle, but understand this is a compromise and not ideal for AWD performance.

In this article we explore why four-tire replacement is usually recommended for Subaru's all-wheel-drive system, when two-tire replacement might be considered, how to choose tires for a Subaru, and practical maintenance steps to protect your drivetrain and handling.

Why four tires are typically recommended for Subaru AWD

How the AWD system influences tire wear

The Subaru Symmetrical AWD distributes torque to all four wheels with a central differential. When tires wear unevenly, their circumference and rolling resistance can diverge, causing the system to compensate in ways that can accelerate wear on drivetrain components or alter handling.

Risks of mismatched tires on AWD

Uneven tread depths or mixed brands can create differences in grip and rotation speed between the front and rear axles, which can lead to vibrations, noise, or unwanted drivetrain engagement, especially in slippery conditions.

• Uneven wear creates differences in tire circumference, which can cause AWD to work harder or engage unevenly.


• Replacing all four keeps tread depth levels uniform, ensuring consistent traction and mechanical harmony across the drivetrain.


• Maintaining matched tires reduces risk of drivetrain noise, vibration, and potential transfer-case wear over time.


• Best results for handling, stability, and predictable braking are achieved when all tires share identical performance characteristics.

For Subaru owners, aligning tire size, model, and wear on all four corners is the simplest way to preserve the intended handling dynamics and avoid cascading wear on the AWD system.

When you might consider replacing only two tires

Situations where two-tire replacement is considered

There are scenarios where a two-tire replacement may be considered, typically due to budget constraints or when the remaining two tires are near new and have similar wear. However, there are important caveats for AWD Subarus:

• All tires must be of the same size and model (or as prescribed by the vehicle manual) to prevent mismatched circumference on the axle pair.


• If you replace only two tires, installers commonly place the new tires on the rear axle to help with stability on slippery surfaces.


• Ensure the older tires have tread depth within a narrow range of the new ones (often within 2/32 inch) to minimize drivetrain and handling issues.


• Plan to replace the remaining two tires soon as wear continues to diverge, and schedule a rotation/inspection to maintain AWD balance.

Note that this is a compromise and not ideal for AWD performance; the safest and most reliable option is usually four new tires.

How to choose tires for a Subaru

Key considerations for tire selection

Choosing tires for a Subaru involves matching the vehicle’s drivetrain needs, typical driving conditions, and your climate. Consider the following guidelines:

• Prefer tires with a symmetric tread pattern and uniform performance across all four corners to minimize differences in rolling resistance and contact patch.


• Use the same brand, model, and size on all four tires when possible; if replacing two, ensure the replacement tires match the existing tires’ size and type exactly.


• Consider all-season tires for year-round use, or winter/snow tires for cold climates; for harsher winters, dedicated snow tires on all four wheels are recommended.


• Check the load index and speed rating to match your Subaru’s specifications; some trims require higher load capacity tires.


• Audit treadwear and warranty; some manufacturers offer treadwear warranties that cover replacement if wear is abnormal.

After selecting a tire, professional installation ensures proper mounting, balancing, and wheel alignment to preserve AWD integrity.

Practical steps and maintenance for Subaru AWD

Maintenance practices to protect AWD and tires

Maintenance routines help preserve tire life and the health of the AWD system. Follow these steps:

• Rotate tires regularly, typically every 5,000–8,000 miles (8,000–12,000 km) to even out wear across axles.


• Check tread depth on all tires and monitor for unusual wear patterns; replace tires if wear exceeds the recommended limit (commonly 2/32 inch or less).


• Have wheel alignment checked if you notice pulling, vibrations, or uneven wear; misalignment costs can accelerate tire wear and affect AWD balance.


• Ensure tires are inflated to the recommended pressure for front and rear; under- or over-inflation can lead to uneven wear and worse handling.


• Seasonal considerations: use winter tires where appropriate; store non-seasonal tires if you switch between summer and winter tires.

Consistent maintenance and using the same tires on all wheels are the best ways to preserve Subaru AWD performance and longevity.

Summary

For most Subaru owners with symmetrical all-wheel drive, replacing all four tires at once is the simplest and safest approach to maintain uniform handling, traction, and drivetrain health. If budget or timing requires replacing only two tires, ensure they are the exact same size and model as the existing tires and place them on the rear axle, but plan for a full four-tire replacement as soon as possible. Regular rotations, proper inflation, and alignment checks are essential for preserving AWD performance over time. Always consult your owner’s manual or a Subaru technician for model-specific guidance.

How long do tires usually last on a Subaru?

When you're driving with Subaru tires, you can expect to have them for approximately 50,000 miles. Multiple factors play a role in why tires wear out, and we're going to spotlight them further.

Do I need to replace all four tires on a Subaru?

Yes, for most Subarus, you will need to change all four tires at once because its all-wheel-drive (AWD) system requires tires with very similar tread depths to prevent damage to the drivetrain. If the tread depths are not uniform, it can put stress on the differential and other AWD components, which can lead to costly repairs. A tire can only be replaced individually if the tread depth is within about 2/322 / 322/32 of an inch of the other three tires. 
Reasons to replace all four tires on a Subaru

• AWD system requirements: A Subaru's all-wheel-drive system requires all four tires to have a nearly identical rolling circumference to function correctly and prevent damage to the differential. 
• Uniformity and performance: Four new tires will provide the same level of traction, handling, and overall performance, ensuring your vehicle maneuvers and handles predictably, especially in adverse conditions. 
• Preventing costly damage: Mismatched tire diameters can cause the AWD system to bind, leading to vibrations and potential damage to the drivetrain components. 

Exceptions and alternatives

• If the other tires are nearly new: You may be able to replace just one tire if the other three are still very new and have a tread depth of at least 8/328 / 328/32 of an inch. 
• Check the tread depth difference: If you are replacing a tire but the others are not worn out, you can measure the tread depth on the remaining tires. If the new tire's tread depth is within about 2/322 / 322/32 of an inch of the others, you may be able to get away with replacing just the one. 
• Tire shaving: If a new tire cannot be found that matches the tread depth of the remaining three, it is possible to have a new tire "shaved" to match the circumference of your existing tires. 
• Replacing two tires: Replacing two tires on the same axle is sometimes an option, but it is still better to replace all four for Subaru's AWD to prevent potential long-term issues. 

Is it bad to only replace one tire on AWD?

Yes, it is bad to only replace one tire on most AWD vehicles because the difference in diameter can damage the drivetrain, transmission, and differential. Replacing only one tire can cause the AWD system to constantly compensate for the new tire's different circumference, leading to premature wear and potential damage to expensive components. 
Risks of replacing only one tire on AWD

• Drivetrain damage: The constant compensation by the AWD system can cause excessive heat and stress, potentially damaging the differential, transfer case, or transmission. 
• Traction and control issues: A new tire has more grip than the others, which can lead to imbalanced traction when accelerating, braking, or turning, potentially causing accidents. 
• Increased fuel consumption: The system working harder to maintain balance can lead to increased fuel consumption. 

Alternatives to replacing only one tire

• Replace all four tires: This is the most recommended option to ensure even wear and proper system function. 
• Replace in pairs: If you cannot replace all four, replacing two tires at a time is a better option than replacing just one. Some mechanics recommend replacing two tires on the same axle, while others recommend replacing all four to be safe. 
• Find a "tire shaving" service: Some specialty tire shops can shave a new tire to match the tread depth of the other tires, allowing you to replace just one with less risk. 
• Check the manufacturer's recommendation: Some manufacturers allow for a small difference in tread depth (e.g., 2/32 to 4/32 of an inch). If the worn tires are still relatively new, you may be able to replace just one without issue. 

When you might get away with replacing one tire

• If the other three tires are almost new and the tread difference is minimal, you may be able to replace just one. 
• If the vehicle has a part-time 4-wheel drive system, replacing one tire may have less impact. 

Ultimately, it is always best to consult your owner's manual and a professional mechanic before deciding what to do.

What year to stay away from a Subaru Outback?

You should be wary of Subaru Outback years such as 2013–2014, 2017–2018, and 2020 due to common problems like excessive oil consumption, transmission issues, and electrical faults. Additionally, the 2010–2011 models may have transmission, engine, and brake line problems. Older generations, like 2005–2009, are known for head gasket issues and oil leaks.
 
2010–2014

• Excessive oil consumption: The 2013 and 2014 models are frequently cited for this issue, which was due to faulty piston rings and can lead to engine failure. 
• Transmission issues: Both the 2010 and 2012 models are reported to have transmission problems, including rough shifting and failure. The 2010 is also known for torque converter issues. 
• Electrical problems: Some models in this range have reported electrical faults. 
• Headlight issues: 2011 models, in particular, had problems with headlights that burned out or melted. 
• Brake line issues: The 2010 model had issues with faulty brake lines. 

2017–2020 

• Electrical issues: These models were plagued with electrical system problems, from the 2017 and 2020 models. 
• Weak windshields: The 2017 and 2020 models are notorious for easily cracked windshields. 
• Transmission problems: Some owners reported issues with the Continuously Variable Transmission (CVT) in the 2017 and 2020 models. 
• Fuel range display malfunction: Some 2018 models had issues with the fuel pump and the fuel range display. 

Older generations

• 2005–2009: These models are known for costly head gasket failures, engine leaks, and catalytic converter failures. 
• 1994–1999: This generation had issues with cracked cylinder heads and premature engine failure. 
• 2000–2001: This period is when Subaru was transitioning ownership, leading to transmission issues in these models. 

Modern models (2015+)

• While later models generally saw improvements, some issues persist. The 2023 Outback had problems with the infotainment system, and the 12V battery was prone to draining.