Georgia Mechanic Calls Out Shop That Replaced Tire With Wrong Size. Then He Reveals How to Tell What Size You Need

Changing tires is one of those car maintenance jobs you can’t avoid. 

Depending on the type of vehicle and tire quality, replacements typically happen every three to five years, costing anywhere from a few hundred dollars to over a thousand.

While plenty of drivers choose to swap them at home, most prefer to let an auto shop handle it. It’s straightforward work, and you assume the pros won’t make mistakes.

But as one Georgia mechanic pointed out, even a simple tire change can go wrong.

A Mechanic Spots a Mistake In Tire Size

In a TikTok posted to the account of Auto Fitness (@autofitness1), a repair shop in Gainesville, Georgia, a mechanic walks viewers through a frustrating discovery.

“Some of the things that we see at Auto Fitness, and heck, as long as I’ve been in the business, just blow my mind how it happens,” he says at the start of the clip.

He then explains the most basic rule of all: “On the front, inside of every driver’s door, there’s a placard that tells you what size tire should be on your car. Check this out.”

He points the camera at the placard of a customer’s car. It reads 235/55R19.

Then, he moves to the back left tire. That one is 225/55R19. “Before you get crazy in the comments, give me a second here,” he continues, bracing viewers for what’s next.

The front left tire is also 225/55R19. Same for the right front. But when he shows the right rear tire, the size matches the placard: 235/55R19.

“How does that happen?” he asks. His own answer follows: “People don’t pay attention. Crazy.”

“We’ve got to do better as repair shops!” the mechanic writes in the caption. “People come to us, trust us and then we do this! Infuriating, female senior citizen, we’ve got to do better!”

What Do the Numbers of a Tire’s Size Mean?

If you’ve ever looked closely at the side of your tires, you’ve seen a string of numbers and letters like 235/55R19. Here’s what they mean. 

The first number shows the tire’s width in millimeters. In this case, the tire measures 235 mm from sidewall to sidewall.

The R stands for radial construction. That means the tire was built with reinforced materials layered across the tread, while the sidewalls stay flexible.

The last number indicates the wheel’s diameter in inches. In other words, this tire is meant to fit a 19-inch wheel.

Together, these markings make sure you’re using the right size and type of tire for your car. 

Does It Matter If Your Tires Aren’t All the Same Size?

Mixing and matching tires might not sound like a big deal. After all, the numbers are close enough. But experts warn that it can affect more than just appearances.

First, tire size and diameter have to match for a reason. When they don’t, even small differences can throw off your speedometer and impact how your braking system and suspension respond. 

A slight mismatch changes the way the car grips the road, especially when the weather takes a turn.

Traction also takes a hit. Different tread patterns and compounds don’t behave the same way, which can cause one tire to grip while another slips. 

Drivers might not notice it at low speeds, but it can quickly turn dangerous during sharp turns or on wet pavement.

Then, there’s the issue of wear. Tires that aren’t uniform won’t wear evenly, which cuts their lifespan short and can push the entire vehicle out of alignment.

Over time, that extra stress spreads to the drivetrain. Components like the differential and transfer case take on added strain and may break down sooner.

On top of all that, insurance and warranty coverage could be on the line. Some manufacturers and providers refuse to honor claims if mismatched tires are part of the equation.

In other words, a “small” mistake can turn into a costly one.

What Do Viewers Think About Tires Being the Wrong Size? 

The clip sparked plenty of conversation in the comments section, with many people throwing out theories on how this could’ve happened.

“Because lazy tire shops sell what they have in stock instead of ordering the correct tire,” one person wrote.

Another user downplayed the mix-up. “That is terrible attention to detail,” they wrote. “However that just means the tire is just 10mm wider than the others which is a hair under 1/2in. I’d be concerned with the height and diameter which are the same 55/R19.”

Others felt it came down to cost-cutting. “They go to these small cheaper tire shops and whatever size they have that fits is the one they put on,” one commenter said.

Someone else shared their own experience: “Happened to me from a Valvoline. Blew a tire on a 12-hour road trip.”

Motor1 has reached out to Auto Fitness for more information.