How much do 33-inch Tires Affect the speedometer?

How much do 33-inch Tires Affect the speedometer?

Affiliate Disclosure: When you buy a product via our links, we sometimes earn a referral fee. Learn more

The locomotive industry has always worked on the versatility and pragmatism of design that will add jazz to the vehicle’s appeal and better performance.

Initially, the cars came with small circumference tires while marching towards the 2020s; the locomotive companies started manufacturing cars with bigger and broader tires for better suspension and firm road grip.

Today the vehicle with bigger wheels is considered more hi-tech and VIP in the market. At times, to stay in vogue, drivers themselves upgrade the tire size of their vehicles.

Moving up to a 33-inch tire will pose a serious question: How much does a 33″ tire affect the speedometer?

How much do 33-inch Tires Affect the speedometer?

In case if you are installing tires of 33 inches in your vehicle, it will affect the speedo meter reading. In addition to the speedometer reading, this change will also affect the reading on the odometer and the fuel mileage gauge.

33 inch tire

This happens for a simple reason, by installing a tire of a larger circumference, the distance covered is more per revolution of the tire than the previous one.

However, this happens as the speedometer calculates the speed based on the RPM set for the last lower circumference tires. Let’s discuss the matter in detail.

What is Plus-Sizing/Upsizing?

When we install bigger wheels in our vehicles, the process is known as plus-sizing, moving from a lower-circumference tire to a higher-circumference tire with a larger diameter.

It’s also called upsizing. However, plus-sizing the original set tire diameter of the car/vehicle should always be considered.

It is recommended that the new tire diameter should not exceed the range of 103% of the original set height or diameter of wheels for the vehicle. That means you are given leverage to play by 3% more tire height but don’t stretch the limit any further.

How does Upsizing to 33-inches Affect the Car Speedometer?

When we upsize our vehicle, like moving to tires around 33 inches in diameter, we increase the car’s height; the tire width is also improved along with its circumference. All these changes dramatically affect the reading on your speedometer.

Plus-sizing your car with a 33-inch tire will show a reading on the speedometer a little lower than the vehicle’s actual speed. If your speedometer shows a reading of 60MPH, it moves at a rate of around 65-66MPH at a difference of 9%.

upsizing 33 inch tire

So upsizing increases the speed of the vehicle and the distance covered due to the larger circumference of the tire; however, the readings on both the speedometer and odometer are displayed according to the settings for the previous tire diameter.

Calculating the Actual Reading for 33” Tire on the speedometer

Generally speaking, this up-gradation leaps around a 9% increase in the speed of the vehicle, which is not shown by the speedometer. To calculate the increase in speed, you have to get down to some mathematical calculations.

Step 1

Calculate the values (diameter) of the tires

New Tire / Original Tire

Step 2

Calculate the difference between the values of the new tire and the original one.

New Tire – Original tire = Difference

Step 3

Now you have to divide the difference by the original tire size value

Difference/Original Tire = V

Step 4

Now you have to multiply this value by 100 to get your speedometer’s added speed percentage.

V X 100 = Percentage Difference for Speed

Now, this is the percentage of the different speeds of your speedometer that you have attained after installing the 33 inches tire in your vehicle.

Advantages of Upsizing to 33 inches Tire

The new 33 inches tires will provide more road grip to the vehicle as their larger circumference, and wider width offers more resistance and gets good contact with the road; this will be felt while driving on turns as the car will be more stable and firm on the road.

As upsizing adds to the height of the vehicle, so the driver will get a better ground clearance while driving, and these tires also accommodate a larger brake disk. Last but not least, the bigger tires add a lot of flashiness to the design value of the vehicle.

Disadvantages of Upsizing your vehicle to 33 inches Tires

Firstly the upsizing of the car to 33 inches tire will cost you a handsome amount of money.

The new 33 inches wheels will alter the reading to some extent on both the speedometer and the odometer. Lastly, it also affects the fuel gauge reading and consumes more fuel. 


Up-sizing your vehicle is in vogue for design manifestations and higher speed ranges. Now the question arises; how much does a 33-inch tire affect the speedometer?

Well, they affect the speedometer to quite an extent ranging from a difference of about 8 – 9% more than shown on your speedometer.

The exact value can be calculated by taking a percentage difference between the original and the installed tires.

Leave a Comment