## Measuring Tire and Wheel Runout
Runout is the measurement of how much a tire or wheel wobbles or deviates from its true circular path as it rotates. Excessive runout can cause a variety of problems, including:
Uneven tire wear
Vibration
Steering problems
Reduced fuel economy
There are two main types of runout:
1. Radial runout measures the wobble of a tire or wheel from side to side.
2. Lateral runout measures the wobble of a tire or wheel from front to back.
## How to Measure Tire Runout
You can measure tire runout using a dial indicator or a runout gauge.
### Dial Indicator Method
1. Place the dial indicator on a magnetic base and position the tip of the indicator against the sidewall of the tire.
2. Rotate the tire slowly and observe the reading on the dial indicator.
3. The maximum reading on the dial indicator is the amount of radial runout.
### Runout Gauge Method
1. Place the runout gauge on the tire and position the gauge so that the pointer is touching the sidewall of the tire.
2. Rotate the tire slowly and observe the reading on the gauge.
3. The maximum reading on the gauge is the amount of radial runout.
## How to Measure Wheel Runout
You can measure wheel runout using a dial indicator or a runout gauge.
### Dial Indicator Method
1. Place the dial indicator on a magnetic base and position the tip of the indicator against the rim of the wheel.
2. Rotate the wheel slowly and observe the reading on the dial indicator.
3. The maximum reading on the dial indicator is the amount of lateral runout.
### Runout Gauge Method
1. Place the runout gauge on the wheel and position the gauge so that the pointer is touching the rim of the wheel.
2. Rotate the wheel slowly and observe the reading on the gauge.
3. The maximum reading on the gauge is the amount of lateral runout.
## Acceptable Runout Limits
The acceptable runout limits for tires and wheels vary depending on the type of vehicle and the size of the tire or wheel. However, as a general rule of thumb, the following runout limits are acceptable:
Radial runout:
Tires: 0.020 inches (0.5 mm)
Wheels: 0.010 inches (0.25 mm)
Lateral runout:
Tires: 0.030 inches (0.75 mm)
Wheels: 0.020 inches (0.5 mm)
## Fixing Runout
If you find that your tires or wheels have excessive runout, there are a few things you can do to fix the problem:
Have the tires or wheels balanced. This will help to correct any imbalances in the weight of the tires or wheels, which can cause runout.
Have the tires or wheels trued. This will involve removing the tires or wheels from the vehicle and using a machine to reshape them so that they are perfectly round.
Replace the tires or wheels. If the tires or wheels are damaged or worn beyond repair, you will need to replace them.
## Conclusion
Measuring tire and wheel runout is an important part of maintaining your vehicle. By keeping the runout within acceptable limits, you can help to prevent a variety of problems, including uneven tire wear, vibration, steering problems, and reduced fuel economy.
