can you use a car with different size tires

[AmeliaLee]

No, you should not drive a car with different size tires. While it might be physically possible for short distances in an emergency, it is dangerous and can cause significant damage to your vehicle's all-wheel drive (AWD) or four-wheel drive (4WD) systems, brakes, and suspension. The core issue is that mismatched tires have different overall diameters, which causes the wheels to rotate at different speeds. This confuses the vehicle's computer systems, leading to premature wear and potential mechanical failure.

The most critical risk is to AWD/4WD systems. These systems are designed with a center differential or similar component that allows for slight speed variations between axles during normal turns. However, permanently different tire sizes create a constant speed difference, causing the differential to work continuously. This generates excessive heat, leading to rapid wear and a costly failure. For modern cars, even the anti-lock braking system (ABS) and traction control (TCS) rely on accurate wheel speed data from sensors; mismatched tires provide false data, compromising these vital safety systems.

Other problems include inaccurate speedometer and odometer readings, poor handling, and uneven tire wear. The only potential exception is if you have a non-driven axle (like on a rear-wheel-drive truck) and the mismatched tires are on the front, but this is still not recommended due to safety system interference.

Potential Issue	System Affected	Consequence
Drivetrain Binding & Overheating	AWD/4WD Center Differential	Costly repair/replacement, potential stranding
Compromised ABS/Stability Control	Anti-lock Brakes, Traction Control	Increased stopping distances, loss of control in emergencies
Inaccurate Speedometer	Instrument Cluster	Speeding tickets, incorrect maintenance intervals
Uneven Tire Wear	Tires, Suspension	Shortened tire life, need for earlier replacement
Poor Handling & Traction	Chassis, Steering	Reduced vehicle stability, especially in wet or icy conditions

If you have a flat and must use a temporary spare tire (a "donut"), it is always smaller than your regular tires. The manufacturer's instructions explicitly warn to drive at reduced speeds (often below 50 mph) and for short distances only to reach a repair shop. This underscores that different tire sizes are a temporary, emergency measure, not a long-term solution. Always replace tires in sets of at least two (on the same axle) and ideally as a full set of four to maintain vehicle safety and performance.

[DiJulia]

It's a really bad idea. I learned this the hard way after a blowout. I put a slightly different tire on just one axle to save money. Within a week, my car started shuddering when I turned, and the traction control light kept flickering. My mechanic said I was putting massive stress on the all-wheel-drive system. It cost me way more to fix the potential damage than just buying two new matching tires would have. Don't risk it.

[Kevin]

Think of your car's drivetrain as a team. All four tires need to be the same size to work together smoothly. If one is different, it's like a runner with a limp—the whole system is thrown off balance. This puts extra strain on the components that make your car move and stop safely. It's not just about wear and tear; it's about how the car responds in a sudden swerve or on a slippery road. Your safety systems are designed for matched tires.

[GemmaLynn]

Beyond the safety risks, it's often against the law. Vehicle codes require your car to be maintained in a safe operating condition. Using significantly mismatched tires can be considered a equipment violation. More importantly, if you were in an accident, an insurance adjuster would likely note the improper tires. This could complicate your claim or even be used to assign partial fault, arguing that your vehicle was not roadworthy.

[SanTaylor]

The rule is simple: all four tires should be the same size, brand, and model. The only time this changes is with a temporary spare, which is clearly marked for limited use. Even when replacing just two tires, the new ones must be the same size as the existing ones and should be installed on the same axle. If you have an AWD vehicle, most manufacturers are very strict—you should replace all four tires at once, even if one is damaged, to avoid drivetrain issues. Consistency is key.