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WHEELS AND TYRES
10
1.3
MAINTENANCE, INSPECTION AND TESTS
A
PRELIMINARY INSPECTION
I. VISUAL INSPECTION
Visually inspect the tyre and replace the same if
any of the following defects are found:
Bumps or bulges in the tread or the side of
the tyre.
Cuts, splits or cracks.
Excessive tread wear or non-uniform tyre
wear.
Remove tyres for replacement preferably when
remaining tread depth in any part of tyre tread
reaches 1.6mm.
Misalignment of wheels and axles in front or rear,
improperly operating brakes or shock absorbers,
bent wheels, worn bushings and other mechanical
problems can cause uneven wear. Hence such
defects should be immediately corrected.
Tyre wear can also be due to faulty steering or
suspension components, Incorrect Steering
geometry adjustments and also worn out wheel
bearing. Hence all these components should be
inspected before arriving at the cause for tyre
wear. Refer their respective groups for procedure
to inspect the components.
II.
PRECAUTIONS
Do not stand over the tyre while inflating. Bead
may break when it snaps over rim’s safety
hump and cause serious personal injury.
Do not exceed specified pressure when
inflating. If specified pressure will not seat
beads, deflate, re-lubricate and re-inflate.
While removing tyre from wheel rim and
mounting it back on wheel rim, take precaution
not to damage tyre bead. Use tyre removal
and assembly machines. Damage or cut on
tyre bead may cause gradual loss of air
deflation of tyre.
If wheel rims get damaged in the service, get
wheel rims repaired/replaced immediately.
Running vehicle with damage rim may cause
deflation of tyre and subsequent dislodging of
tyre from rim.
Maintain recommended inflation pressure in
tyre. Over inflation in particular, may cause
puncture or bursting of tyre.
Avoid unequal load distribution on wheels
which may be due to
(a) A difference in the overall diameter of the two
tyres.
(b) The difference in the amount of air pressure in
each tyre.
(c) The contour of the roads.
(d) Axle sag.
FOLLOWING PRECAUTIONS SHOULD BE
TAKEN WHILE
1. Installing wheel assembly on wheel hub
(a) The wheel must be correctly positioned
relative to the hub when mounting on the
vehicle.
(b) To prevent rusting, small amounts of oil may
be applied to the wheel bolts and nuts. Care
must be taken not to over lubricate.
(c) Wheel bolts and nuts should be tightened as
per specified torque value.
NOTE:
Excessive bolt tightening may cause deformation
of bolt causing failure and an insufficient
tightening may cause the wheel loosening.
2.
Removing wheel assembly using a
hydraulic jack.
(a) Follow the jacking instructions.
(b) Make sure to set the jack properly in the jack
point. Raising the vehicle with improperly
positioned jack may damage the vehicle or
causes the personal injury.
(c) Do not carry any other work or never get
under the vehicle supported by jack as it may
cause personal injury.
(d) Do not start or run the vehicle while supported
by jack.
(e) Do not lift the vehicle with any anyone seated
in the vehicle.
Do not lift the vehicle excessively. Lift up to
sufficient height necessary to remove and change
the wheel.