Q: Should I get wider tires for my car?

Tire size is one of the most common changes that people make to their cars. You can purchase tires that are taller, shorter, wider or skinnier than the factory tires. Many people make these changes simply based on cost when purchasing new tires, but if it is done right, you can change your tire size just enough to benefit from the change. Changing to a wider tire may seem like an easy choice, but as with any change, there are going to be pro’s and con’s based on the change that is made. Knowing how to make an informed decision can assist you in making that choice to go with a wider tire.

The benefits of changing to a wider tire are typically based on small changes in tire size. The width of a tire can be found imprinted on the sidewall. Tire sizes typically read something like P225/55/R16. The first numerical value, in this case the 225, is the width of the tire in millimeters. This number changes is 10 millimeter increments depending on the size you are looking for. It is important to know that when a vehicle is designed, the manufacturer chooses the correct tire size based on what will work on the vehicle with the wheel size that is used and the size of the vehicle. They also figure in cost, meaning that they will typically use a tire that will cost them less to install on the vehicle.

Most vehicles will easily allow for you to change the width of the tire by one size, or 10 millimeters, without any negative affects. Keep in mind that when you go wider, most tires become taller unless you go with a smaller aspect ratio. The aspect ratio of a tire is the middle number in the size. This is a percentage of height based on the width. If you are considering the tire size mentioned previously, the height of the sidewall is 55% as high as the tire is wide. This means that if you want to go wider you should also go to a smaller aspect ratio. This will assist in making sure that the overall tire diameter remains close to the same. By doing this you refrain from affecting things like speedometer calibrations and transmission shift points. If you choose to go slightly wider on the tire you can benefit from having more of the tire tread on the ground. This will typically result in better handling from the tire, as well as more safety as your tires will have better grip to the road surface.

As with any change to a vehicle, if you change it too much you can negatively impact your car. If you go too wide the tires can wear unevenly. Tires that are too wide for the wheels tend to bulge in the middle of the tread causing them to wear excessively in the middle. Going too wide can also cause clearance issues. The tires can end up rubbing on the fender wells and on suspension components causing damage. Tires that are too wide will also cause there to be excessive load on the hub bearings which will cause them to wear prematurely.

Many people also tend to overlook the impact on fuel mileage. Installing wider tires allows for more tire contact to the road. Though this may be good for performance and handling reasons, it is not when it comes to efficiency. Too much contact with the road causes excessive friction making it harder for the engine to get the vehicle moving. This extra load can negatively impact your fuel mileage by as much as 20%.

Changing the size of the tires on your vehicle is not always a bad choice. As long as no drastic changes are made you should not see any negative affects on your vehicle. This will also go for installing new wheels. Wheels that are wider can have similar effects on your vehicle in the long term.