The tire and rim size can vary depending on the car you have. Usually, the bigger the rim, the bigger the tire size. The vehicle manufacturer decides how big the tires should be based on the car’s design, but that doesn’t mean you can’t make changes.
In short, Yes, you can change the tire size on the same rim but you can’t go overboard because the tire size must be compatible with the rim’s width and the size of the wheel well. If you become too overenthusiastic with the tire choice, your car’s handling, fuel average, and grip will be affected.
Factors to Consider when Changing the Tire Size on the Same Rim
The Rim’s Width
The rim’s width comes into play if you are looking to install wider tires. You are better off measuring the rim’s width and then searching for the most compatible tire. Usually, it is safe to go 1 or 2 sizes above in width.
For example, if you have a 195-width tire, you can go as far as 225, but even that would be on the edge. Therefore, it’s best to check the user manual and find the rim’s width and get a tire size based on the specifications.
Wheel Well Size
Apart from the width, you can also alter the thickness of a tire. This is the measurement of the sidewall. If the tire is too thick, it will stand tall in the wheel well, and it might not fit as well.
So, make sure you measure the wheel well before installing a thick radial. You could also make way for the bigger tire by altering the suspension and raising the car a bit so that there is more space for the tire to sit.
Thankfully, tire manufacturers already measure this in their tires. You will see that a tire that is too wide, does not have a thick sidewall and vice versa. Therefore, unless you are thinking of installing drag radials, you don’t need to worry too much.
Altering the Front Suspension
Bigger tires do not affect the suspension in the rear as much as they affect the front. That’s because you have to turn the car using the front wheels, and if a tire is too big, it interferes with the turning and handling of a vehicle. The tie rod, steering control arm, and other suspension components are designed to work with a specific size of tire.
If you do not respect that limit, you might damage the suspension, or worse get into an accident because of the alteration. If you are willing to change the entire front suspension, you can install a tire as big as you want. But that costs a lot of money. Something that not a lot of people can afford. So, it’s better to stay within the limits prescribed by the manufacturer.
Why Change the Tire Size?
There are several reasons why someone would be looking to change the tires:
Wider or bigger tires offer more road grip because, with them, more of the rubber gets into contact with the tarmac. If you drive on the highway regularly, you will feel the difference in handling and traction.
Most people are searching for that with their stock tires, but the grip is usually not there. It is only after you install high-quality radials on your car that you get the confidence to drive fast and turn willingly.
Some people want bigger tires because they look beautiful. The car community is in awe of large wheels and how they look on certain vehicles. That’s why you will find huge wheels on regular cars a lot of the time. They don’t serve any purpose other than to impress the onlookers.
Aesthetics and grip aside, there are some people in the car fraternity that are looking to extract more mileage out of their tires. It is common knowledge that slim tires offer better fuel economy. They work that way since a small patch of rubber gets into contact with the road. As a result, there is less friction, and the engine doesn’t have to work too hard to move the car forward.
Disadvantages of Changing Tire Size
If you install smaller tires, you might sacrifice too much road grip, which in turn, will affect your driving style. The reduced grip will make you more prone to accidents as you won’t be able to stop in time or maneuver the car properly.
Bigger tires make the engine work too hard, and thus they increase fuel consumption. You should install big tires only if fuel costs are not an issue for you.
Conclusion on changing Tire Size on Same Rim
Changing the tire size comes with a lot of advantages and disadvantages. You should weigh them both equally before making a decision.
Robert Anderson is a world class motorhead who rebuilt his first carb at age 10, his first engine at age 15, and completed his first full hotrod build when he was just 18! Previously, he has ran a part warehouse, delivered pizzas, and managed the service department for a $20 million/year revenue dealership. Robert knows cars like few others and he is passionate about sharing his knowledge.