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Chassis practice questions

22 questions from the diesel and heavy truck practice test.

Chassis practice test

10 questions, graded as you go, with the reason for every answer. No sign-up.

What this covers

Sample questions

Two tires are being matched as a dual pair. What is the generally accepted maximum difference in their overall diameters?

  1. 1/2 inch
  2. 1 inch
  3. 2 inches
  4. 1/4 inch
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D. 1/4 inch

Duals should be within 1/4 inch in diameter (about 3/4 inch in circumference). A larger mismatch makes the bigger tire carry more load and the smaller one scrub, overheating both.

Reference: TMC recommended practice for dual tire matching; ASE T5 Suspension and Steering task list (wheels and tires)

How is a hub-piloted disc wheel centered on the hub?

  1. By ball-seat nuts that seat in chamfered stud holes in the wheel
  2. By tapered wedges driven between the rim and a cast spoke wheel
  3. By a tapered sleeve fitted over each one of the wheel studs
  4. By machined pilot pads on the hub that fit the wheel center bore
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D. By machined pilot pads on the hub that fit the wheel center bore

On a hub-piloted system the wheel's center hole rides on pilot pads on the hub, and two-piece flange nuts only clamp it. Ball-seat nuts in chamfered holes describe the older stud-piloted system; the parts must never be mixed.

Reference: ASE T5 Suspension and Steering task list, wheels and tires (wheel mounting systems); TMC RP 222

Where is oil applied when installing two-piece flange nuts on a hub-piloted wheel?

  1. On the stud threads and between the nut and its flange
  2. On the wheel mounting face and the brake drum face
  3. On the flange face that seats against the wheel
  4. Nowhere; everything must be assembled completely dry
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A. On the stud threads and between the nut and its flange

A couple of drops of oil on the threads and between the nut body and its captive flange give a consistent clamp load at the specified torque. Lubricant on the mating faces of the wheel, hub or drum lets the joint slip and loosen.

Reference: ASE T5 Suspension and Steering task list, wheels and tires (wheel installation); TMC RP 222

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