Wheels, Tires and Hubs

Question 1

1. Name the two (2) basic styles of wheels used on heavy equipment.
   a)
   b)

Answer 1

a) spoke wheels

b) disc wheels

Question 2

2. Explain the main differences between the two wheel styles mentioned in question 1.

Answer 2

Spoke wheels are supported by bearings and can be considered as a type of hub. Disc
wheels are fastened to a hub.

Question 3

3. Identify the two (2) types of disc wheels in terms of how they are piloted.
   a)
   b)

Answer 3

a) stud piloted - centred by the studs and nuts

b) hub piloted - centred by the machined hub pads

Question 4

4. When dual tires and wheels or rims are used, a spacer must also be used. Explain the
   purpose of that spacer.

Answer 4

The spacer ensures that the two tires are separated sufficiently to prevent contact
during nonnal operation.

Question 5

5. It is permissible to use any style of wheel nut when mounting stud piloted wheels.
   a) true
   b) false

Answer 5

b) false; Only use cone/ball type tapered wheel nuts.

Question 6

6. It is permissible to use one stud piloted wheel and one hub piloted wheel as a dual
   wheel set.
   a) true
   b) false

Answer 6

b) false; Only use a set of stud piloted OR a set of hub piloted wheels as a dual
wheel set.

Question 7

7. Identify two (2) main types of tires, in terms of the air retention methods.
   a)
   b)

Answer 7

a) tube type

b) tubeless type

Question 8

8. Tire tread designs can be of two general styles. Name and explain when those styles
   are typically used.
   a)
   b)

Answer 8

a) rib - non-traction, steering, on-highway use, trailer

b) lug or block - traction applications

Question 9

9. Explain the two (2) major types of tire construction in common use.
   a)
   b)

Answer 9

a) bias ply - angled cords (plies) built up into layers
b) radial ply - steel plies at 90 degrees to the bead, with steel reinforcing belts on the
tread circumference

Question 10

10. Tires are matched by checking the size on the side wall of the tires.
    a) true
    b) false

Answer 10

b) false; Tires must be measured for circumference and diameter and be matched
within allowable limits.

Question 11

11. Identify the equipment that could be used to measure tires in the process of matching
them together.
a)
b)
c)

Answer 11

a) a tape measure
b) a large square or a matching stick (large caliper)
c) a tire straight edge or a length of string held tightly across all tires

Question 12

12. When matching tires on a tandem axle assembly, the front axle tire set can be
    matched, but slightly different from a matched rear axle tire set.
    a) true
    b) false

Answer 12

b) false; Ideally both axle tire sets are identically matched.

Question 13

13. Identify the two (2) main tire inflation problems. Of these two explain which is worse
    and why.
    a)
    b)

Answer 13

a) under-inflated - worse - heat can destroy tire

b) over-inflated - faster tire wear

Question 14

14. As an apprentice, explain what you could do to prevent personal injury when
    working around tires/wheels and rims.

Answer 14

Get training in safe tire/wheel/rim handling. Follow all instructions. Ask for help
when uncertain. Know the most likely explosive force trajectories and stay clear.

Question 15

15. Explain what visual checks you should do before moving any tire assembly.

Answer 15

Visually inspect the tire/wheel/rim for signs of overheating, damage, cracks and
mismatched parts.

Question 16

16. Describe the first thing you would do prior to removing a tire assembly from a
    vehicle for repair or before working on a loose tire assembly

Answer 16

Remove all air from the tire by removing the valve core. Push a wire into the valve
stem to ensure no blockage exists and all air is out.

Question 17

17. It is permissible to weld or braze on a steel wheel.
    a) true
    b) false

Answer 17

b) false; Do not weld, braze, rework or heat a wheel or wheel components.

Question 18

I 8. Describe the equipment you would use to safely inflate a tire and wheel or rim
assembly.

Answer 18

Place the tire assembly in a safety cage. Use a length of air hose with a pressure
gauge and an inflating/deflating mechanism attached. Stand clear and seat the beads
with no more than 276 kPa (40 psi) pressure.

Question 19

19. It is permissible to mix wheel and rim side rings and lock rings.
    a) true
    b) false

Answer 19

b) false; Never mix wheel/rim components. Always match the parts together.

Question 20

20. Axle wheel hubs generally use a set of two tapered bearings. These bearings do not
    require adjustment.
    a) true
    b) false

Answer 20

b) false; Bearings operating as sets must be adjusted.

Question 21

21. Wheel bearings are only lubricated by grease.
    a) true
    b) false

Answer 21

21. b) false; Oil is often used.

Question 22

22. All wheel studs have right-hand threads.
    a) true
    b) false

Answer 22

b) false; Some have left-hand threads.

Question 23

23. Identify the two (2) general types of wheel balance problems.
    a)
    b)

Answer 23

a) static - centralized heavy spot across a tread or rim

b) dynamic - heavy spot on a side of a tire tread or wheel rim

Question 24

24. Which tire imbalance is identified by the word bounce?

Answer 24

static imbalance

Question 25

25. Which tire imbalance is identified by the word shimmy?

Answer 25

dynamic imbalance

Question 26

26. Wheel weights used for balancing tire assemblies must be a specific shape and contour. a) true b) false

Answer 26

a) true

Question 27

27. Cracks in steel wheels can be welded and the wheel can then be returned to service. a) true b) false

Answer 27

b) false; Never weld a cracked wheel.

Question 28

28. To prevent internal tire and wheel/rim damage air lines should be free of water and oil. a) true b) false

Answer 28

a. true

Question 29

29. Wheel or rim chording is used to describe flat spots on the wheel/rim edges. a) true b) false

Answer 29

a. true

Question 30

30. Long tire life is only obtained by a joint effort between the operator and the service technician. a) true b) false

Answer 30

a. true