2000 Ford Focus Owner's Manual - Page 212

Maintenance and care Replacing the tires Replace tires when the wear band is visible through the tire treads. When replacing full size tires, never mix radial, bias belted, or bias type tires. Use only the tire sizes that are listed on the Certification Label. Make sure that all tires are the same size, speed rating, and load carrying capacity. Use only the tire combinations recommended on the label. If you do not follow these precautions, your vehicle may not drive properly and safely. Make sure that all replacement tires are of the same size, type, load carrying and tread design (e.g., All Terrain", etc.), as originally offered by Ford. Failure to follow these precautions may adversely affect the handling of the vehicle and make it easier for the driver to lose control and roll over. Tires that are larger or smaller than your vehicle's original tires may also affect the accuracy of your speedometer. 212