Brakes & Wheels
300
Wheel and Tire Balancing
It is desirable from the standpoint of tire wear and coach handling to maintain the proper balance of
front wheel and tire assemblies. All wheels intended for use on the front wheels, such as those switched
during tire rotation and those installed as new or repaired replacements, should be accurately balanced.
This may be accomplished by two types of procedures: “On Vehicle” or “Off Vehicle.” The “On Ve
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hicle” is more desirable, however, because all the rolling components (drums, bearings, seals, etc.) are
included in the balancing procedure and, therefore, any existing unbalanced condition is corrected.
Wheel balance is the equal distribution of weight of the wheel and tire assembly around the axis of rota
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tion. Wheels can be balanced “Statically” and “Dynamically.” Wheels must be balanced statically first
and then dynamically.
Static Balance
Static balancing is also called “still” balancing. It is the equal balance of the weight of the wheel and
tire around the axis of rotation so that the assembly has no tendency to rotate by itself, regardless of its
position. Static unbalance causes a hopping or pounding action (up and down) which frequently leads to
wheel flutter or wheel tramp.
Dynamic Balance
An out-of-round condition greater than 3/32" (2.4 mm) cannot be
corrected with balancing. Such an assembly is not suitable for installation
on the front axle of a coach. Check for this condition as described earlier
in this manual.
Dynamic balance is also called “running” balance. It means the wheel must be in static balance and also
run smoothly at all speeds on an axis which turns through the center line of the wheel and is perpendicu-
lar to the axis of rotation.
To ensure successful and accurate balancing, the following precautions must be attended to.
• The wheel and tire must be clean and free from all foreign matter. The tires should be in good con-
dition and properly mounted with the balance mark on the tire, if any, aligned with the valve.
• Bent wheels which have runout over 3/32" (2.4 mm) should be discarded or straightened before
balancing.
• Use of wheels on the rear axle should be governed by the condition of the assembly and whether
the roundness defect affects the quality of the ride.
• When balancing wheels and tires, it is recommended that the instructions and procedures covering
the wheel balancer be followed closely.
Summary of Contents for LOW FLOOR
Page 18: ...Specifications 18...
Page 58: ...Preventive Maintenance 58...
Page 110: ...Engine 110...
Page 138: ...Transmission Driveline Rear Axle 138...
Page 182: ...Suspension 182...
Page 260: ...Air System 260...
Page 420: ...Electrical System 420 Deutsch DT Series Connectors...
Page 421: ...Electrical System 421...
Page 422: ...Electrical System 422 Deutsch HD 10 Series Connectors...
Page 423: ...Electrical System 423...
Page 424: ...Electrical System 424 Deutsch HD 30 Series Connectors...
Page 425: ...Electrical System 425...
Page 442: ...Heating Air Conditioning 442...
Page 492: ...Body and Interior 492 Figure 11 33 USSC Seat Assembly...
Page 493: ...Body and Interior 493 Figure 11 34 USSC Seat Suspension Assembly...
Page 495: ...Body and Interior 495 Figure 11 37 Seat Air Connections...