1.How to Read Tire Sizes.
A. SECTION WIDTH:
Section width is the width of an inflated tire in millimeters at its widest point.
B. ASPECT RATIO:
Section width and height are used to determine the Aspect Ratio. The lower the ratio, the shorter the sidewall.
The "R" stands for "radial"construction.
D. RIM SIZE:
The diameter of the wheel (not the tire) in inches.
E. LOAD INDEX:
The load index number corresponds to the maximum load-carrying capacity of the tire. Refer to load index values in the chart opposite.
F. SPEED RATING
The speed rating corresponds to the tire's maximum speed capability (under optimal conditions).
Right inflation pressure is one of the most important aspects to deliver maximum performance in terms of safe driving, riding comfort and monetary savings.
The optimum tire inflation pressure is indicated on a vehicle placard or vehicle owner's manual. The maximum inflation pressure for safe driving is marked on the tire sidewall. Generally, the optimum inflation pressure is about 90% of the maximum level. In addition, inflation pressure must be adjusted to load. The best time for checking air pressure is before long distance driving or at least once a week.
Overinflation or Underinflation can cause serious or fatal injury.
Alignment generally refers to the adjustment of a vehicle's front and rear suspension parts. Proper alignment helps ensure that your vehicle handles correctly and will help increase the life and performance of your tires.
Inch Plus sizing is one important method to improve handling. It is often referred to as "inch up", that means replacing Original Equipment tires and wheels with different specifications.
The process involves mounting a lower aspect ratio tire and a larger diameter wheel on your vehicle while maintain the same overall diameter. Of course, the tire sidewall will become smaller and the tread will become wider as the wheel diameter increases.