Runout

If balancing does not correct a highway speed vibration, or if the vibration occurs at low speeds, runout is the probable cause. Runout can be caused by the tire, the wheel, or the way the wheel attaches to the vehicle. The following procedure should be used:
1. Measure the free runout of the tire and wheel on the vehicle. (A dial indicator with a roller wheel is preferred, but a dial indicator with a button end may be used).
a. Measure lateral runout (side-to-side) on tire sidewall, as close to tread shoulder as possible.
b. Measure radial runout (up-and-down) on the center tread rib. You may need to wrap tape tightly around the center tread rib for better dial indicator contact.
^ Disregard instantaneous indicator needle jumps due to sidewall depressions, tread blocks, etc.
c. Record the total indicator reading, and locations of the high point of runout.
d. Total tire and wheel on-vehicle runout should be less than 1.5 mm (0.060 inch). If lateral or radial runout exceeds this, go on to step 2.
2. Mount the tire and wheel on a dynamic balance machine, and measure the amount of runout, as in Step 1. Record amount of tire-wheel runout and its high point locations.
3. Measure wheel runout.
^ If the wheel exceeds specifications, replace it.
^ If the tire and wheel radial or lateral runout exceeds 1.3 mm (0.050 inch) at the tire tread, go on to step 4.
4. Match mount the high radial runout point of the tire to the low point of the wheel. Reinflate and repeat steps 2 and 3.
5. If tire and wheel runout is within limits when measured off-vehicle, yet is not when measured on-vehicle, rotate the wheel on the vehicle by two wheel studs and recheck runout. Several positions may have to be tried to find the best mounting position on the hub.
6. If tire and wheel runout cannot be reduced to an acceptable level, do the following:
a. Remove tire and wheel from vehicle.
b. Measure wheel stud runout with a dial indicator. Zero the indicator on one stud, then lift button off stud and rotate flange to position the next stud against the indicator button.
c. Record runout on all studs. Dial indicator should read zero when repositioned on first stud checked. If runout exceeds 0.75 mm (0.030 inch), the hub or axle shaft should be replaced.

When a tire is rotated on the wheel, or a tire or wheel is replaced, the assembly must be balanced.