A car is a well-oiled machine, unless it’s an Alfa Romeo (sorry guys, had to do it), so from the factory it operates as optimally as possible. Throughout its lifespan, you need to replace some things, which of course includes the tires, leading me to today’s topic.
Car manufacturers work to make the cars drive the way they do and one aspect that helps is the tires. The rubber on all 4 corners plays a crucial role in safety and drivability, which is why I recommend avoiding those cheap tires that are borderline unsafe.
People have found ways to save money when the need for new tires arises. The solutions range from used tires or overusing the existing ones to getting blemished ones. Somewhere in between is something I see a lot in my surroundings and that’s mismatched tires.
People do this for summer and winter tires, putting the “important” ones on the driven wheels. On a FWD car, the front wheels get winter tires, while the back ones get summer tires. The winter tires go on the back when the season changes.
I can understand the philosophy behind this. The wheels that are steering and accelerating are getting the tires that are designed for that weather, so you’re not missing out on any performance. The rear wheels are just dragging along, so it doesn’t matter what tires you have there. Even though I can understand the idea, I’m not a fan of it–let me explain why.
Should You Drive With Mismatched Tires?
The short answer is no. Most cars aren’t designed to be driven with mismatched tires and doing that can lead to premature wear on additional components. In some more extreme situations, you’ll be looking at performance and safety concerns as well.
What Does it Mean to Drive With Mismatched Tires?
I touched a bit on this, but here’s a more in-depth explanation. Driving with mismatched tires means that not all 4 tires are the same model. I won’t talk about squared or staggered setups, as that’s how some cars come from the factory, so it’s not something you should avoid.
The example from the introduction gave you a good idea of what mismatched tires mean, but that’s not the only one you’ll see. Some people combine tires from the same category, but different manufacturers or the same manufacturer, but a different model. So far, these examples have been in situations where the front and rear tires were different, but there’s a worse example.
I haven’t seen this in a while, but there are cases where people mismatch tires on the left and right sides. It’s mostly seen when people buy used tires. This leads to tires with different dimensions, the most extreme case I haven’t seen, but there are documented cases of it.
Each kind of mismatch is bad in its own way, so let’s dive into each one and see why you shouldn’t even think about this.
Front and Rear Mismatched Tires
This is the most common one, and a splendid example is the one I mentioned with the summer and winter tires. The idea is to have 2 summer and 2 winter tires and rotate them front to back depending on the season and the driven wheels. It’s seen with FWD cars because the front wheels are doing the heavy lifting, so they are the crucial aspect of it.
A summer tire has no performance in cold temperatures, but since they’re on the back, the car should be fine, right? Well, no. Even at slow speeds, you will notice your car getting tail-happy in a corner. As much as we want that in our FWD cars, there are better ways for it. The same goes for braking. Manufacturers set up cars to be front-biased, but that doesn’t mean the rear ones aren’t doing anything. When braking, the rear may get restless, resulting in an unsafe experience and longer braking distances.
With a RWD drive car, things are different, and you won’t see the summer and winter combination of tires, which is a good thing. With these cars, the front tires steer and the rear ones accelerate, so both are important. Here you may see mismatched front and rear tires in terms of the type of tires or models.
Even though it’s not as dangerous as the previous example, it’s still a bad idea. Two different tire models will have different performances–some may stick better on dry roads, while others may be better in wet conditions. Mixing these performances leads to an unbalanced car. The rear could slide more, while the front could be stickier, so you’ll probably be drifting out of your driveway every morning. The same goes for the braking, which won’t be the same as if all 4 tires are the same.
This can be more pronounced when the front and rear tires are different types, like UHP tires on the front and touring tires on the rear. The grip levels will be very different and the car won’t be as balanced as it should be.
Left and Right Mismatched Tires
As I said, it’s not a very common sight on the road, but it’s worth explaining the problem behind it. Just as the tire’s balance gets thrown out the window with front and rear mismatched tires, the same goes for the left and right types. The bigger issue here is that the car’s balance gets thrown to the side, literally.
Imagine this: you have a newer premium tire on the front left, while an older mid-range one is on the right wheel. This is most noticeable in the corners, as the car will turn better on one side and worse on the other. Also, in an emergency braking scenario, you’ll notice the car pulling to one side, the one with the tire that has more grip.
This kind of setup can lead to premature wear on some components. If things aren’t balanced, one side will have more strain, so driving like this for a long time will cause other problems.
Mismatching Tire Sizes
I know some of you will mention the space saver and I’ll explain that in a minute.
All 4 tires have the same dimensions because most cars have a square setup. There are some RWD cars with a staggered setup, which manufacturers designed them to be driven like that, so I’ll skip those. Mismatched sizes mean that on a car with a square setup, one or more tires are with a different size than the intended one.
There are many people that upgrade their tires and wheels and go for a wider tire, something I’ve done as well. The stock tires on my 92 Corolla are 155 wide and the car is now running with 175. I’m getting more grip and worse fuel economy, but at least it doesn’t look like it’s running on bicycle tires.
One way a car can have mismatched sizes is if the fronts differ from the rear tires on a car with a square setup. We see this on FWD drag cars, where the front-end grip is important, and the rears are there just for show. While it works on a dragster, it’s pointless to do on your Civic. Sure, you’ll get more traction, something you won’t notice during your morning commute to work. This isn’t too terrible and there aren’t many safety concerns, but it’s pointless.
A bigger problem is mismatching the size on the left and right sides. It’s a similar story like with mismatching the models or types of tires. The left and right sides won’t have the same levels of grip, causing a problem with steering or braking. This can get worse as mismatching the sizes can lead to different diameters, either left or right, or front and back.
In these situations, the car will lean towards the “smaller” tire and will cause an added strain on the components, leading to damage and costly repairs.
As for the space saver, yes, the tire is smaller than the others and it’s technically mismatched. While that’s true, a space saver is a tire designed to get you to the nearest tire shop to get your flat tire fixed, not for long-term usage.
So, with everything that you’ve read so far, I hope you figured out that mismatching your tires is a bad idea. You’re opening yourself to an unsafe driving experience or one that can lead to unnecessary wear and tear on other components. Yes, there are situations where it won’t cause too many problems, but it won’t solve anything either, so it’s pointless.
We want to get away cheaper when the time comes to get a new set of tires, but this isn’t one of them. With this, I’ll recommend avoiding used ones, something I’ve said plenty of times in the past. Looking for discounts or getting blemished tires are two excellent options to avoid spending top dollar on a new set of tires. The advantage of both is that you won’t compromise on performance or safety.