Final answer:
If larger tires are installed on an SUV, the vehicle travels faster than the speedometer reading. The speedometer's calibration is based on the original tire size, so larger tires cover more distance per revolution, leading to a higher actual speed than indicated.
Step-by-step explanation:
If your speedometer reads 60 mph, but your tires are larger than the factory-installed ones, your SUV is likely moving faster than the speedometer indicates. The speedometer is calibrated based on the circumference of the original tires, meaning revolutions per minute correspond to a specific speed. When larger tires are installed, each revolution covers more ground, but the speedometer doesn't account for this change. Consequently, you are covering more distance in the same amount of time, which equates to a higher actual speed.
Example to Calculate Actual Speed
To calculate the actual speed, you can use a formula based on the ratio of the new tire circumference to the original tire circumference. For example, if the new tires are 10% larger in circumference, then your actual speed is 10% faster than what the speedometer reads.
Therefore, if the speedometer reads 60 mph, the actual speed would be 60 mph + (10% of 60 mph), which is 66 mph. However, the exact ratio would need to be determined based on the specific sizes of the original and new tires.