Changing Tire Size on a Car

Yes, but all vehicle manufacturer specifications must still be met, including load capacity, speed rating, and overall rolling diameter within a reasonable tolerance. Changing size affects speedometer accuracy, ABS and stability control calibration, clearance, and load capacity. Verify any size change with a tire professional before purchasing.

Not necessarily the same number as your door placard. The replacement tire must be inflated to provide the same load capability the original size provided at the manufacturer's recommended pressure. Because different sizes carry different loads at the same pressure, this requires a load and inflation table calculation that a tire professional can do accurately.

As a general guideline, keep overall diameter within about 3 percent of original. Beyond that, speedometer and odometer error becomes significant, ABS and stability control calibration is affected, and on some vehicles transmission shift points are calculated from wheel speed. Larger changes require professional recalibration.

Your new tire's load index must meet or exceed the original specification. Load index requirements do not drop just because the tire is a different size. This matters most on trucks and SUVs that tow or carry heavy loads, where reducing load capacity has direct safety consequences.

Pressure starts with your vehicle's door jamb placard for the OE size. If you have changed size, the correct pressure comes from load and inflation tables matched to your specific tire size, load index, and vehicle weight. Your BFGoodrich dealer has access to these tables and can calculate the right number for your setup.