Why AWD Vehicles Often Need All 4 Tires Replaced — Even If Only One Is Damaged
If you drive an all-wheel-drive (AWD) vehicle and have ever been told you need to replace all four tires because just one is damaged, you’re not alone in feeling frustrated. We hear it all the time — “The other three tires are still fine!”
We get it. Tires aren’t cheap, and being told you need four when only one failed can feel unfair. Our goal with this article is to explain why this recommendation exists, what’s at risk if you don’t follow it, and what options you may still have.
How AWD Systems Work (In Simple Terms)
AWD vehicles are designed to send power to all four wheels. To do this smoothly, the system assumes all four tires are very close to the same diameter.
When tires are evenly worn, this works perfectly. But when one tire is significantly more worn — or brand new compared to the others — that balance is lost.
Even small differences in tire size can cause the AWD system to think a wheel is slipping, forcing it to constantly compensate.
Why Tire Size Differences Matter
As tires wear, their overall diameter gets smaller. A new tire can be several millimetres taller than a worn tire — and that’s enough to cause problems.
On an AWD vehicle, mismatched tire sizes can lead to:
- Constant stress on the center differential
- Overheating of drivetrain components
- Premature failure of expensive AWD parts
In many vehicles, this damage happens quietly over time — until one day you’re facing a repair bill that far exceeds the cost of tires.
Why Replacing Just One Tire Can Be Risky
Manufacturers typically specify a maximum allowable difference in tread depth between tires — often as little as 2/32” to 4/32”.
If your existing tires are beyond that difference:
- Replacing only one tire can void drivetrain warranties
- AWD components may be under constant strain
- Long-term reliability of the vehicle is compromised
This is why many shops — including us — recommend replacing all four tires when one is damaged beyond repair.
“But My Other Tires Still Have Life Left…”
This is the hardest part — and we truly understand how frustrating it feels.
From your perspective, it looks like you’re throwing away good tread. From a mechanical perspective, you’re protecting one of the most expensive systems in your vehicle.
A failed center differential or transfer case can easily cost thousands of dollars, while tires are predictable, preventative maintenance.
Our Approach at Shire Tire
We don’t recommend four tires lightly — and we never ignore how inconvenient or costly it can be.
Our promise is to:
- Explain why a recommendation is being made
- Check tread depth accurately
- Look for safe alternatives where possible
- Help you protect your vehicle long-term, not just today
If you’re unsure whether your AWD vehicle truly needs all four tires replaced, we’re always happy to talk it through and give you clear, honest advice.
Tires you can trust — right at your door.