Looking for a way to occupy the kids on a long winter road trip? Assign them the project of comparing odometer readings with highway mileage markers. A difference of tenth of a mile or two in a 10 mile stretch is not unusual. Oversized tires will cause both your odometer and speedometer to read low.
New tires, with full tread, make fewer revolutions per mile than do bald tires. What happens to all that rubber that’s worn off millions of tires? It accumulates alongside our nation’s highways. Some of this rubber was scrubbed off because the wheels are out of alignment.
Imagine a car, driven about 12,000 miles a year, going down the road with wheels misaligned by just 0.17 inches. The driver must constantly tug at the wheel to keep the car going straight. In effect, the tires are being dragged sideways for the equivalent of 68 miles over the course of a year. This condition, along with under-inflation, increases rolling resistance. End result, tires are wasted away and fuel economy plummets as gas goes out the exhaust.
How do you know if your tires are wearing too quickly or unevenly? Steering irregularities, such as pulling in one direction or wandering, indicate either one tire under-inflated or misaligned wheels.
Information provided courtesy of Car Care