If you drive a 4x4 or all-wheel-drive vehicle, you probably bought it for the extra traction, safety, or off-road capability. What many drivers don’t realize, though, is that these systems are very sensitive to tire differences. While it might seem harmless to replace just one or two tires when they wear out, mismatched tires can cause more damage than you’d expect—especially in AWD and 4WD systems that rely on precise wheel synchronization.
Matching tires isn’t just about tread depth—it’s about protecting your drivetrain, avoiding unnecessary wear, and keeping your vehicle running as it should.
Why Matching Tires Matter on AWD and 4x4 Vehicles
In an AWD or 4WD system, power is distributed to all four wheels, often through a center differential or transfer case. These systems are designed to assume that all four wheels are rotating at the same speed. When tire sizes or tread depths are different, even slightly, it throws off that balance.
Mismatched tires spin at different rates, which causes the AWD system to constantly adjust and compensate. Over time, this puts excessive stress on components like the center differential, transfer case, and drivetrain. In some vehicles, it can lead to system failure or costly repairs, even if the difference between tires is only a few millimeters.
The Problem with Replacing Just One or Two Tires
If one of your tires is damaged, replacing just that tire may seem like the most economical option. However, in AWD and 4WD systems, even a single new tire with deeper tread can create a rolling diameter mismatch with the older tires.
That mismatch causes uneven rotation, and your vehicle’s computer may interpret that as a loss of traction, constantly adjusting torque between wheels, and wearing out the system. In many cases, automakers recommend replacing all four tires at once or shaving the tread of a new tire to match the wear of the others.
Even if your tires are the same brand and model, uneven wear can still cause issues. If the difference in tread depth is more than 2/32 of an inch between tires, you’re already in risky territory for AWD systems.
How Tire Size and Tread Affect Drivetrain Health
Rolling diameter isn’t just a number—it directly affects how your wheels interact with each other. Smaller-diameter tires will complete more rotations over the same distance than larger ones. When one tire is slightly smaller (due to wear), it spins faster than the others, causing torque bind or even excess heat in the drivetrain.
This is especially problematic in systems that don't have an easy way to disengage AWD or 4WD. Over time, components may overheat, wear out, or completely fail, leading to repairs that can cost thousands.
What About 4x4 Systems That Aren’t Always Engaged?
Some 4x4 vehicles only activate four-wheel drive in certain conditions or when manually engaged. While it might seem like mismatched tires are less of an issue in these vehicles, they can still cause problems once 4WD is activated.
When the system is activated—particularly on slippery or uneven terrain—using tires of unequal sizes can cause drivetrain binding, reduced control, and unpredictable handling. Therefore, even part-time 4WD systems benefit from having consistent tire sizes and tread wear. However, if necessary, it is still possible to change only two tires at a time.
Avoid Costly Repairs with the Right Tire Strategy
Replacing all four tires at once might feel like a big expense, but it’s a lot cheaper than a failed transfer case or damaged differential. If you’re dealing with one damaged tire on a relatively new set, tire shaving or matching tread depths might be an option.
Keeping up with tire rotations, alignments, and pressure checks also extends tire life and helps them wear evenly—so you don’t end up in a situation where one needs replacing far ahead of the others.
When it comes to AWD and 4x4 systems, cutting corners on tire replacement can backfire quickly. Consistency is key, and taking care of your tires is taking care of your drivetrain.
If you're unsure whether your tires are still safe for your AWD or 4x4 vehicle, stop by
Rick's Tire & Service in Seattle, WA. We’ll inspect your tread, check for differences, and help you choose the right tire strategy. Call today to schedule a tire check!
