Radial Runout Measurement - Dial Indicator Method
Radial Runout Measurement - Dial Indicator Method
Special Tool(s)
Component Test
Radial Runout
Radial runout is the egg-shaped deviation from a perfect circle and is measured perpendicular to the circumference. On a wheel and tire assembly, this means measuring the center tire tread rib. The center rib is indicative of the condition of the tire as a whole. Total runout is the difference between the maximum-to-minimum gauge reading. The high spot is the location of maximum runout.
Radial Runout Measurement - Dial Indicator Method
1. NOTE: Diagnosis of tire/wheel vibration should not be performed on tires with less than 320 km (198.88 mi). Some initial tire/wheel vibration issues (such as flat spotting) will correct themselves after the tires have been in service for 320 km (198.88 mi).
NOTE: Loaded run-out measurements are the preferred method for verifying tire serviceability. While a dial indicator can be used to optimize the position of the tire on the wheel, the unloaded run-out measurement cannot accurately determine if the tire should be removed from service.
NOTE: The following procedures should be used if normal diagnostics leads to a potential runout issue.
NOTE: Some vehicles may exhibit a wheel and tire vibration caused by excessive runout. Radial runout measurements can be taken using a dial indicator and should be measured with the wheel and tire assembly mounted on a suitable wheel balancer. The dial indicator should be mounted securely to eliminate gauge movement when measuring runout.
NOTE: Use only the 204-354 any time tire pressures are measured to be sure that accurate values are obtained.
Make sure that the tire pressures are set to the correct pressure as indicated on the VC (Vehicle Certification) label.
2. Using a tire crayon, record the vehicle position on the inward sidewall of all 4 tires.
3. Remove the wheel and tire assemblies. REFER to Wheel and Tire .
4. NOTICE: Make sure that the correct wheel balancer adapters are used when mounting the assembly to the wheel balancer or damage to the wheel may occur.
NOTE: Make sure that the wheel and tire assembly is clean and free of foreign material prior to installation on the balancer.
Mount the wheel and tire assembly on a suitable wheel balancer using the correct wheel balancer adapters as shown. REFER to the list of recommended wheel balancer adapters on the PTS website.
5. NOTE: Masking tape can be applied on the center tread rib to allow for a smoother measuring surface. Some fluctuation of the gauge reading is expected. Observe the overall sweep of the gauge from the highest to the lowest spot on the tire.
Position a suitable dial indicator and stand with the dial indicator on the center tread rib.
1. Rotate the wheel and tire assembly (or wheel) to locate the low spot.
2. Adjust the runout gauge to read 0.
3. Rotate the wheel and tire assembly one complete revolution to make sure that the low spot has been found and that the dial indicator returns to a 0 reading.
6. While slowly and constantly rotating the wheel and tire assembly (or wheel), measure the radial runout.
- Note the variance (runout) from 0 on the dial of the gauge.
- If the runout reading of a wheel and tire assembly is greater than 1.14 mm (0.0449 in), locate and temporarily mark the high spot and runout reading on the sidewall of the tire and carry out the Match Mounting procedure to optimize the wheel and tire assembly. REFER to Wheel-to-Hub Optimization .
- If the runout reading of a wheel and tire assembly is 1.14 mm (0.0449 in) or less, permanently mark the high spot and the runout reading on the inward sidewall of the tire for reference during future wheel and tire service. Balance the assembly and install the wheel and tire on the vehicle using the Wheel-to-Hub Optimization procedure. REFER to Wheel-to-Hub Optimization .
