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JR
TIRES/WHEELS (Continued)
or "steps." Tread "dips" and "steps" can be identi-
fied by spikes of the dial indicator gauge.
(c) If runout exceeds limits, mark the original
location of the tire on the wheel at the valve stem
(Fig. 3). Also, mark the tire and wheel to indicate
the original high spot of the assembly and record
the runout measurement.
(d) If runout exceeds limits, the tire will need to
be dismounted from the wheel to verify wheel vs.
tire contribution. Refer to Wheel Runout below.
Fig. 3 Marking Tire
1 - REFERENCE MARK
2 - EXAMPLE HIGH SPOT ON TIRE
3 - WHEEL
4 - VALVE STEM
(3) Lateral Runout. Lateral runout for the vehi-
cle system as well as the tire and wheel assembly
should be less than 0.76 mm (0.030 inch). The same
procedure and theory described for radial runout can
also be applied to identify and reduce lateral runout.
(4) Wheel Runout. This runout check is per-
formed as follows:
(a) Dismount the tire from the wheel.
(b) Mount the wheel back on the wheel balancer.
(c) Measure radial runout of the wheel at the
tire bead seat (Fig. 4). Runout should not exceed
0.254 mm (0.010 inch) for aluminum wheels and
0.508 mm (.020 inch) for steel wheels. Replace the
wheel if it exceeds the limit.
(d) Measure lateral runout of the wheel at the
tire bead seat (Fig. 5). Runout should not exceed
0.762 mm (0.030 inch) for all wheels. Replace the
wheel if it exceeds the limit.
Fig. 4 Checking Radial Runout Of Wheel
1 - MOUNTING CONE
2 - SPINDLE SHAFT
3 - WING NUT
4 - PLASTIC CUP
5 - DIAL INDICATOR
6 - WHEEL
7 - DIAL INDICATOR
Fig. 5 Checking Lateral Runout Of Wheel
1 - MOUNTING CONE
2 - SPINDLE SHAFT
3 - WING NUT
4 - PLASTIC CUP
5 - DIAL INDICATOR
6 - WHEEL
7 - DIAL INDICATOR
(5) Match Mounting. If the wheel runout is
within specifications, tire and wheel assembly runout
can be improved by re-indexing (match mounting)
the tire to the wheel as described below.
(a) Remount the tire on the rim 180 degrees
from its original location (Fig. 6). Ensure the tire
bead is properly seated.
TIRES/WHEELS
22 - 3
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