Yes putting bigger tires on your car or other vehicle can throw the speedometer off by at least 13 percent.
The bigger tires can cause your speedometer to indicate a speed that is too slow by almost 13 percent.
So while your speedometer may be saying you're going 40 MPH you may actually be going 50 MPH or even 55 MPH.
That means that while you're thinking you're not speeding you may actually be speeding and not even realize it because of the bigger tires.
So you need to compensate for the reduction in the accuracy of the speedometer when you put bigger tires on your vehicle.
The bigger tires may also use more fuel to get your vehicle the same amount of distance and miles.
When you put bigger tires and wheels on your car the bigger tires and wheels cover more ground in one complete revolution.
So that's a reason that your speedometer gets thrown off.