Can One Mismatched Tire Ruin an AWD Drivetrain?

All-wheel drive (AWD) vehicles are designed for superior traction, better handling, and improved safety on slippery or uneven surfaces. But they rely on a precise balance between all four wheels to function correctly. That’s why tire size, tread depth, and even wear levels need to be consistent across all tires. Replacing just one tire or mixing brands and tread patterns might seem harmless, but for AWD vehicles, it can lead to unexpected and costly issues.

It’s a common question: “Do I need to replace all four tires if only one is damaged?” Let’s find out.

Unlike front-wheel or rear-wheel drive vehicles, AWD systems continuously distribute power between all four wheels. They do this through differentials and a transfer case that adjusts torque depending on road conditions and wheel speed. If one wheel is rotating faster or slower than the others because its tire is smaller (even slightly), the system may misinterpret this as slippage.

To compensate, the system works harder to equalize the rotation. Over time, this extra effort creates stress on drivetrain components like the transfer case, center differential, or viscous coupling. These parts are not designed to operate under constant load imbalance and can wear out prematurely.

Even if your tires are the same brand and model, differing tread depths can still create problems. A new tire has deeper tread and a slightly larger overall diameter than a worn tire. This means it will rotate fewer times per mile compared to the worn tires, causing the AWD system to register incorrect wheel speeds.

You might not notice the difference immediately, but over time, your drivetrain components will.

If one tire is damaged beyond repair and the others are relatively new, your technician may be able to shave the new tire down to match the remaining ones. This process removes some tread from the new tire so it matches the diameter of the others. However, this only works if the difference is small and the other tires still have a substantial amount of tread life left.

In many cases, especially if the existing tires are halfway worn or more, the safest and most cost-effective solution is to replace all four. Although it may be more expensive upfront, it can prevent damage that would be far more costly to repair later on.

If you continue driving with mismatched tires on an AWD vehicle, you could be facing damage to components that aren’t cheap to replace. A failed transfer case or differential repair can run into the thousands. What’s worse, these components don’t usually give much warning before failure. One moment your car drives fine, and the next, you’re stuck on the roadside.

Not only does this impact the performance of your AWD system, but it can also compromise your safety. Uneven tire traction affects handling, especially in wet or icy conditions, where the benefit of AWD should be most noticeable.

To avoid running into this issue, make tire rotation a routine part of your vehicle maintenance. Regular rotation helps tires wear evenly, which is especially important for AWD systems. You should also monitor tread depth regularly. If one tire is wearing out faster than the others, it could indicate an alignment issue or other mechanical problem that requires attention.

Stick with the same brand, model, and size when replacing tires, and avoid mixing different types of tires on the same vehicle. Even slight differences in performance or rubber composition can affect how the system reacts.

If you drive an all-wheel drive vehicle and need tire service or replacement, don’t guess—get professional guidance. At Morin Brothers Automotive in San Luis Obispo, CA, we understand how sensitive AWD systems can be to tire inconsistencies. Our team will help you determine whether tire shaving is possible, if full replacement is needed, and how to protect your vehicle’s drivetrain in the long run.

Visit Morin Brothers Automotive today to ensure your tires are keeping your AWD system and your vehicle running at peak performance.