When car performance upgrades come to mind, everyone thinks about the engine. While that is important, it’s not the only place you should be looking to improve performance. Improving your tires could allow you to improve performance without breaking the bank.
Changing tires is quick and easy but can be expensive if you buy both new tires and a new rim. This article answers the question: Can you change tire size on the same rim?
Can you change the tire size without changing the rim?
Yes, you can use a different tire size on the same rim for as long as the new tire's inner diameter and the rim's outer diameter are the same numbers in inches. Knowing how to read the numbers and codes on the sidewall is necessary to know which tire is most compatible with your rim.
How to read tire size?
On the sidewall of your tire, you will see something like:
The only significant numbers to know the tire size are the three digits after the first letter and the numbers after the slash, separated by another letter (that we won’t discuss).
Tire width and height
The first three numbers represent the tire width in millimeters. The example above says that the tire is 205 mm wide.
The following two numbers after the slash represent the ratio of the tire’s height relative to its width. In this case, the tire’s height is 55% of its width. Doing the math, the tire’s height is 205 mm*0.55=112.75 mm. This ratio manifests in the size of the tire’s sidewall, i.e., the length from the inner edges to the outer edges of the tire.
The bigger the percentage, the larger the sidewall.
(The following letter tells us how the tire is constructed, which is not important for this article.)
This helpful tire size calculator will help you find the right wheel and tire combination for your car. This can be helpful if you’re looking to improve performance or just want a new look.
The last two digits measure the inner diameter of the tire in inches. This number also tells us the diameter of the rim that would be compatible with the tire.
Now, if you change tires on the same rim, you can only choose tires that are either wider or taller (i.e., have a higher sidewall) but with the same inner diameter.
But, of course, both options come with their respective pros and cons.
What happens if you put a wider tire?
If you opt for wider tires, your tire will have more surface area to grip on the ground and more friction on the road. However, they are more resistant to rolling, meaning each wheel roll consumes more gas.
✅ More grip
✅ More friction
❌ Resistant to rolling
If you are big on aesthetics, wider tires are for you since wider and flatter tires look more appealing on most cars.
What happens if you put on a taller tire?
Opting for tires with higher sidewalls can increase your car’s ground clearance and cover up the fender well, which is an advantage if you find your fender well unpleasant. However, if it’s too high, it can bump on the fender wells during bumpy rides.
This can damage your fender wells or cause uneven tire wear.
✅ Increase ground clearance
✅ Covers fender well
❌ Can bump on the fender well
Make sure that there is enough wiggle room between the tire and the wheel well for off-road rides. Otherwise, the constant impact may damage the parts behind the fender well.
When it comes to accessorizing, most 16 to 24 year olds focus on new wheels and tires. This was followed by exterior body modifications and chemical upgrades (additives, special oil etc). Rounding out the top five are interior upgrades and lighting changes.Specialty Equipment Market Association (SEMA)
Customizing your tire size might give you a better driving experience. This will only happen if you know exactly what changes you need and want.
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Otherwise, you risk experiencing the disadvantages of customized tire sizes, which include overstressing your gear ratio. Larger tires can affect your car’s transmission since they require more accelerating power. Depending on your chosen tire, you may also experience slight changes in braking, turning, and fuel consumption.