Component Test- Radial Runout

WARNING: This page is about a different car, the 2015 Ford F-150. However, it is still accessible from the selected car via links, so may be relevant.

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.

Courtesy of FORD MOTOR COMPANY

Item	Description
1	High spot
2	Low spot

Radial Runout Measurement - Loaded Hunter Road Force® Method

NOTE: Diagnosis of tire/wheel vibration should not be performed on tires with less than 198.8 mi (320 km). Some initial tire/wheel vibration issues (such as flat spotting) may correct themselves after the tires have been in service for 198.8 mi (320 km). This procedure is intended to assist with the diagnosis of wheel and tire assembly runout and/or force variation issues. The Hunter Road Force® 9700 Series Wheel Balancer measures the wheel and tire assembly's loaded runout and the tire's radial spring rate. The balancer then converts the runout into pounds of force (termed as Road Force). Measuring loaded runout (Road Force) is more effective than measuring unloaded runout using a dial indicator.

1.

Using a tire crayon, record the vehicle position on the inward sidewall of all 4 tires.

2.

Remove the wheel and tire assemblies. REFER to: Wheel and Tire .

3.

NOTE: Use only a digital tire pressure gauge 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 label.

4.

NOTE: 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.

NOTE: The wheel balancer inflation station must be turned OFF for tires with inflation pressures of 60.0 psi (414 kPa) or above.

Mount the wheel and tire assembly on a suitable wheel balancer using the correct wheel balancer adapters as shown in illustration.

Courtesy of FORD MOTOR COMPANY

Item	Description
1	Wheel balancer
2	Cone
3	Wheel and tire assembly
4	Finger plate
5	Balancer wing nut

5.

Measure the Road Force®.

Temporarily mark the high spot and the Road Force® value on the sidewall of the tire. If the wheel and tire assembly Road Force® value is greater than 9 kg (20 lb), carry out the Match Mounting procedure to optimize the wheel and tire assembly.
If the wheel and tire assembly Road Force® value is 9 kg (20 lb) or less, permanently mark the high spot and the Road Force® value 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.