A Tire On My AWD Toyota Highlander Suddenly Went Flat On the Highway and the Sidewall Is Now Destroyed Making Me Upset That I Have to Spend $1,000 to Buy 4 New Tires Now

Many owners of all-wheel drive vehicles end up buying four new tires when they destroy just one. There are sound reasons behind this, but it is not necessary in every case. Let’s take a look at the options this Toyota Highlander owner has available to them, but first, here is B.M.’s unedited comment posted to a popular Facebook group.

I think I already know the answer to this, but yesterday my tire suddenly went flat on the highway. Somehow burst on the sides? No idea what happened since they were fairly good tires. Being an all wheel drive car, I'll probably have to drop $1000 on four new tires, won't I?
The discoloration on the tire happened after it went flat. Bought this car from a Toyota dealership, not even a year ago. (Edited slightly for grammar, profanity, and the substitution of “roadside assistance” for an abbreviation)

Accompanying the post, was an image of the flat and destroyed tire. This was not a repairable puncture. The sidewall is badly torn and degraded. Is this a one-off event? It is not. Member of the group D.W. also showed an image of her Highlander with a badly damaged sidewall.

One bright spot in this story was pointed out by B.M., who said, “Thank goodness for the full-size spare underneath.” That spare tire prevented the vehicle from having to be towed. Not only is towing a waste of time, but replacing the tire becomes another time drain, since you’re without a car to drive to the tire store. Spare tires are found on every top-selling 2025 model year vehicle except one. Can you guess what top-selling vehicle lacks a spare tire?

Do You Need To Buy Four Tires If Your AWD Vehicle Destroys Just One?
When an all-wheel drive vehicle loses one of its tires, buying four is definitely a possibility. If the tread has only worn a couple of millimeters, you can buy just one. Your owner’s manual will have details that apply to your specific model and trim. A flat tire with a new set is actually a blessing in disguise, since the tread is mostly at its new depth, and therefore, you need only buy one new tire, not four.

However, if your tires are past 1/3 of their lifespan, it is very likely you will need to buy four tires if you have an all wheel drive vehicle has a flat that cannot be repaired. The reason for this is that the rolling diameter of one of your tires will be different than the other three. Although vehicles use differentials so that they can turn and have the wheels turn at different rates while cornering, the differentials are not designed to work continuously with one wheel rotating at a different speed than the wheel on the other end of the differential. Using one tire that is a different size can cause the differential to fail. This is a very expensive repair to deal with.
Here are some opinions and insights from the Toyota Highlander group. 
J. l. says, "Yes you will need four tires. "
J.A. concurs with what that member said, saying, “You will need to buy four tires.”

However, many members are skeptical that four tires are necessary. Some of these members point out practical alternatives. One alternative is to purchase a new tire and have the tread shaved down to the same depth that the other three tires on the car have.
S.T. says “Tire Rack will shave your tires down to whatever depth you want.”
J.S. had another idea. he said, “Try finding that same Tire used on eBay or Craigslist. I had good luck doing so and found a tire that had similar tread, so I bought it and saved myself from having to buy four tires.”

Lifespan of Tires
If your tires have plenty of tread, but are aging, you may still be wise to replace all four. A.U. commented, “Even with good tread rubber, quality deteriorates for a time, usually past six years. Check the four-digit number near the DOT if it's still readable. That will indicate the week and year it was manufactured.”

Trust Your Mechanic
One way to find out if you need to buy four tires would be to ask your trusted independent mechanic particularly if that mechanic does not sell you tires. Many shops will sell tires to customers, but only do so as a courtesy. Those shops that are not in the primary business of selling tires have no reason to try to sell you extra. Ask your trusted mechanic if you need to buy one or four. They may ask you to measure the tread, but that is easy to do. if your car is drivable on your spare, you could even stop in and have them look the tires over to see what your options are.

How Long Can You Drive On the Spare
If your car has a compact temporary spare tire,  it will have a limited range rating. Typically, this is 50 miles at around 50 mph. The idea is that the spare tire will get you to a tire shop or back and forth to work one day. However, if your spare tire is a full-size matching tire, you can drive many, many more miles, and you can drive at full speed. Just ensure that the tire is properly inflated. Many spare tires lose pressure over time. For a full guide on how to care for the spare tire in a Toyota Highlander, please see our story titled How to Check and Maintain the Spare Tire in Your Toyota Highlander Before It’s Too Late.

Getting a flat tire is always a hassle. One thing you don't want to do is have a flat tire turn into a differential replacement job.  Follow your owner's manual and look to your independent mechanic for help if you have a flat tire and are not sure if you need to buy four.

What do you think? Is the four tires when one is damaged concept just a way to sell tires, or is it really needed? Tell us in the comments below. 

John Goreham is a long-standing member of the New England Motor Press Association and an expert vehicle tester. John completed an engineering program with a focus on electric vehicles, followed by two decades of work in high-tech, biopharma, and the automotive supply chain before becoming a news contributor. He is a member of the Society of Automotive Engineers (SAE int). In addition to his eleven years of work at Torque News, John has published thousands of articles and reviews at American news outlets. He is known for offering unfiltered opinions on vehicle topics. You can connect with John on LinkedIn and follow his work on his personal X channel or on our X channel. Please note that stories carrying John's by-line are never AI-generated, but he does employ grammar and punctuation software when proofreading and he also uses image generation tools. 

Images by John Goreham