Can you go one size bigger for tires?
As a general rule of thumb, it's safe to fit a tire up to 20 millimeters wider than stock on the original rim. The actual width of the tire will vary depending on the width of the rim: The tire will expand 5 millimeters for every half inch (12.5 millimeters) increase in rim width. via
Can I change tire size without changing rims?
Wheels and tires are not interchangeable words. Tires are a part of the wheel setup. For instance, your vehicle has a set size of rims, but you can buy different sizes of tires to fit those rims, as long as the middle of the tires is the correct size. via
Do bigger tires increase RPM?
Simple math dictates this fact; in order to cover the same amount of ground, a small tire must rotate more times than a larger tire. Because of this, the taller the tire, the faster it propels the vehicle, even as the vehicle's engine produces the same number of rotations per minute (RPM). via