How many RPMs is there to go 30mph?

To determine the RPMs needed to go 30 mph, you need to know the tire's diameter and the gear ratio of the vehicle. For example, a typical passenger car tire with a diameter of about 26 inches would have a circumference of approximately 82 inches. At 30 mph, the tire would rotate about 1,000 times per minute (RPMs) when considering a standard gear ratio. However, this can vary significantly based on the specific vehicle and tire size.