27 Stability & Load Handling Practice Questions & Answers

Every Stability & Load Handling practice question from the Forklift Operator (OSHA) Practice Test, with the correct answer and a short explanation.

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1. On a sit-down counterbalanced forklift, the stability triangle is bounded by which three points?
- A.The two front wheel contact points and the centre pivot of the rear axle✓ Answer
- B.The two rear wheel contact points and the centre pivot of the front axle
- C.The two front wheel contact points and both rear wheel contact points
- D.The fork tips, the mast base, and the counterweight at the rear
OSHA's stability appendix describes the triangle as the two front wheel contact points plus the pivot point at the centre of the rear steer axle. Because that axle swings on one centre pin, it supports the truck at a single point, so a four-wheel truck still has only three points of support.
Ref QB-BH6UF3Source: 29 CFR 1910.178 Appendix A, A-4 (stability triangle)Report a problem with this question
2. A four-wheel counterbalanced forklift is said to have a three-point suspension. What makes that true?
- A.The front axle is rigid, so that the two drive wheels count together as a single support point
- B.The rear tyres are solid and smaller, so they carry too little weight to count as supports
- C.The steer axle is attached to the frame by a pivot pin at its centre, so it acts as one point✓ Answer
- D.The mast carries the third point, transferring load to the frame ahead of the front axle
The rear steer axle is hung from the frame on a single pivot pin at its centre, so the axle can rock and delivers its support to the frame at that one pin. That is why almost all counterbalanced trucks behave as three-point suspensions regardless of wheel count.
Ref QB-UZBZ24Source: 29 CFR 1910.178 Appendix A, A-4 (three-point suspension)Report a problem with this question
3. A loaded forklift remains stable as long as which condition holds?
- A.The weight of the load stays below the weight of the counterweight built into the truck
- B.The combined truck-and-load centre of gravity stays inside the stability triangle✓ Answer
- C.The centre of gravity of the load by itself stays between the two forks and the backrest
- D.All four wheels keep firm contact with the floor throughout the lift and the travel
Stability depends on where the vertical line of action through the combined truck-and-load centre of gravity falls. While that line lands inside the triangle the truck is stable; once it moves outside, the truck may tip in the direction the centre of gravity has gone.
Ref QB-CHH6N4Source: 29 CFR 1910.178 Appendix A, A-4 (combined centre of gravity)Report a problem with this question
4. What happens to the combined centre of gravity of truck and load when the load is raised on the mast?
- A.It moves downward, because the mast transfers more of the load weight into the frame
- B.It moves upward, so the same load is less stable at height than it was near the floor✓ Answer
- C.It shifts rearward toward the counterweight, which makes the truck more stable overall
- D.It stays at the same height, since raising the forks does not change any weight
Lifting the load raises the combined centre of gravity, and a higher centre of gravity needs only a small tilt, bump or turn to swing its line of action outside the stability triangle. That is why a load that sits safely at floor height can tip the truck once it is elevated.
Ref QB-VZPB85Source: 29 CFR 1910.178 Appendix A, A-4 and A-7 (dynamic stability)Report a problem with this question
5. A loaded forklift is driven across the face of a slope rather than straight up or down it. Which way does the combined centre of gravity move?
- A.It stays centred, because the mast is still vertical relative to the truck
- B.Toward the uphill side of the triangle, where the counterweight holds it
- C.Toward the front axle, because the forks point across the face of the grade
- D.Toward the downhill side of the triangle, reducing lateral stability✓ Answer
Gravity acts straight down while the truck is tilted, so the line of action shifts toward the downhill side of the stability triangle and the margin against a lateral tipover shrinks. Trucks should travel straight up and down a grade rather than across it.
Ref QB-DHVGT5Source: 29 CFR 1910.178 Appendix A, A-6 (lateral stability); ANSI/ITSDF B56.1, travel on gradesReport a problem with this question
6. A forklift turns while travelling. Which way does the combined centre of gravity shift?
- A.Toward the outside of the turn, away from the way the truck is steering✓ Answer
- B.Straight rearward toward the counterweight, because the rear wheels steer
- C.Toward the inside of the turn, following the path that the steer wheels take
- D.Straight forward over the front axle, because the drive wheels pull the truck
In a turn the mass of truck and load keeps moving in the original direction, so the combined centre of gravity moves toward the outside of the turn. A tighter radius or a higher speed increases that outward shift and can push the line of action past the side of the stability triangle.
Ref QB-WZ2PD6Source: 29 CFR 1910.178 Appendix A, A-6 and A-7 (lateral and dynamic stability)Report a problem with this question
7. A load makes the load moment slightly larger than the truck's vehicle moment. What does the operator notice first?
- A.The truck tips forward immediately and the load is thrown off the forks entirely
- B.The hydraulic lift stalls and the mast refuses to raise the load any further
- C.The rear wheels lift and steering is lost, although the truck has not tipped✓ Answer
- D.The drive wheels spin because the extra weight is taken off the front axle
When the load moment only slightly exceeds the vehicle moment, the truck rotates just far enough about the front wheels to lift the rear axle off the floor, and steering control is lost because the steer wheels no longer touch the ground. A far larger excess is what produces a full forward tipover.
Ref QB-EH8UY6Source: 29 CFR 1910.178 Appendix A, A-3 (moments and loss of steering control)Report a problem with this question
8. In the see-saw model of forklift stability, what acts as the fulcrum?
- A.The points where the front wheels contact the ground✓ Answer
- B.The base of the mast where it is bolted to the frame rails
- C.The vertical face of the forks where the load rests
- D.The pivot pin at the centre of the rear steer axle
OSHA defines the fulcrum as the truck's axis of rotation when it tips forward, which is the front wheels' points of contact with the ground. Load weight ahead of that axis and truck weight behind it are the two moments that decide longitudinal stability.
Ref QB-XZDZJ7Source: 29 CFR 1910.178 Appendix A, A-1 (definition of fulcrum)Report a problem with this question
9. In OSHA's stability appendix, the counterweight of a forklift is best described as which of the following?
- A.The mast and carriage weight acting behind the front wheel axis
- B.Ballast the operator adds to the frame when a load is oversized
- C.The weight of the battery pack by itself on an electric lift truck
- D.Weight built into the truck's structure behind the front axle to offset the load✓ Answer
The counterweight is weight designed into the truck's basic structure behind the front axle, and its moment about the fulcrum is what resists the forward tipping moment of the load. Operators may not add counterweight of their own, because that changes the machine the manufacturer rated.
Ref QB-FHK668Source: 29 CFR 1910.178 Appendix A, A-1 (definition of counterweight); 29 CFR 1910.178(q)(6)Report a problem with this question
10. A forklift's vehicle moment about the front axle is 120,000 in-lb. The operator picks up a 4,000 lb load whose centre of gravity sits 33 inches ahead of the front axle. What does comparing the moments predict?
- A.132,000 in-lb of load moment, which the counterweight cancels out, so it is safe
- B.96,000 in-lb of load moment, using the 24 in rated centre, so it is safe
- C.132,000 in-lb of load moment, which exceeds the 120,000 vehicle moment, so the truck tips forward✓ Answer
- D.120,000 in-lb of load moment, exactly equal, so the truck sits at its limit
A moment is weight multiplied by its distance from the fulcrum, so 4,000 lb x 33 in = 132,000 in-lb of load moment against 120,000 in-lb of vehicle moment. Because the load moment is the larger of the two, the truck rotates forward about the front wheels.
Ref QB-5UKM2KSource: 29 CFR 1910.178 Appendix A, A-3 (moment = weight x distance)Report a problem with this question
11. What does 'load centre' mean on a forklift data plate?
- A.The horizontal distance from the fork face to the load's centre of gravity✓ Answer
- B.The vertical distance from the floor to the centre of gravity of the raised load
- C.The distance from the front axle to the centre of gravity of the truck unloaded
- D.The point midway between the two forks where the load should be centred laterally
Load centre is the horizontal distance measured out from the vertical face of the forks or attachment to the line of action through the load's centre of gravity. For a uniformly dense load it is half the load's depth, so a load that reaches farther out has a larger load centre and a larger tipping moment.
Ref QB-MBEFFJSource: 29 CFR 1910.178 Appendix A, A-1 and A-5.2 (load centre)Report a problem with this question
12. A counterbalanced forklift is rated at 5,000 lb. At what load centre is a truck of that size normally rated?
- A.12 inches
- B.24 inches✓ Answer
- C.48 inches
- D.36 inches
Trucks with rated capacities of 30,000 lb or less are normally rated at a 24-inch load centre, which matches a uniformly loaded 48-inch pallet. Any load whose centre of gravity sits farther out than 24 inches reduces what the truck may safely carry.
Ref QB-4U8AVHSource: 29 CFR 1910.178 Appendix A, A-5.2 (24-inch load centre)Report a problem with this question
13. Trucks with rated capacities above 30,000 lb are normally rated at which load centres, and why?
- A.12 or 18 inches, because heavier loads must be carried closer in
- B.24 inches, the same as every other truck, so ratings stay comparable
- C.36 or 48 inches, because larger trucks handle physically larger loads✓ Answer
- D.60 or 72 inches, because the forks on such trucks are much longer
Capacity ratings are stated at a load centre typical of the loads the truck will actually handle, and trucks above 30,000 lb normally carry bulkier loads, so they are rated at 36 or 48 inches. The rated load centre is therefore not a universal number and must be read off the individual truck's plate.
Ref QB-KB35AHSource: 29 CFR 1910.178 Appendix A, A-5.2 (load centre ratings above 30,000 lb)Report a problem with this question
14. A data plate reads 5,000 lb at a 24-inch load centre. A uniformly loaded pallet measures 60 inches from the fork face outward. What is the heaviest it may weigh?
- A.2,000 lb
- B.5,000 lb
- C.4,000 lb✓ Answer
- D.2,400 lb
The allowable load moment is 5,000 lb x 24 in = 120,000 in-lb, and a uniformly loaded 60-inch pallet has its centre of gravity at 30 inches, so 120,000 / 30 = 4,000 lb. Dividing by the full 60-inch length instead of the 30-inch load centre is the classic error and gives 2,000 lb.
Ref QB-7UAADNSource: 29 CFR 1910.178 Appendix A, A-5.3 (allowable load moment)Report a problem with this question
15. A data plate reads 4,000 lb at a 24-inch load centre. A uniformly dense crate measures 64 inches from the fork face outward. What is the most it may weigh?
- A.1,500 lb
- B.2,000 lb
- C.4,000 lb
- D.3,000 lb✓ Answer
The allowable moment is 4,000 lb x 24 in = 96,000 in-lb, the crate's load centre is half of 64 inches, or 32 inches, and 96,000 / 32 = 3,000 lb. The same answer comes from the ratio shortcut, 24 / 32 x 4,000 lb.
Ref QB-PB55TMSource: 29 CFR 1910.178 Appendix A, A-5.3 (capacity at an increased load centre)Report a problem with this question
16. A data plate reads 8,000 lb at a 24-inch load centre. The load centre of the load actually being handled measures 30 inches. What is the maximum weight the truck may carry?
- A.8,000 lb
- B.6,000 lb
- C.6,400 lb✓ Answer
- D.10,000 lb
The allowable moment is 8,000 lb x 24 in = 192,000 in-lb, so at a 30-inch load centre the limit is 192,000 / 30 = 6,400 lb. Capacity always falls as the load centre grows, so an answer above the plated 8,000 lb cannot be right.
Ref QB-6UXX7MSource: 29 CFR 1910.178 Appendix A, A-5.3 (rated capacity x rated load centre)Report a problem with this question
17. A truck is plated at 5,000 lb at a 24-inch load centre. With a carton clamp fitted, its attachment plate reads 4,200 lb at a 24-inch load centre. The operator is asked to move a 4,600 lb load whose centre is 24 inches out. What is correct?
- A.The load is within the 5,000 lb original rating, so the lift may proceed carefully
- B.The load may be lifted if it is kept below 12 inches and driven at walking pace
- C.The load exceeds the 4,200 lb plated capacity with the clamp fitted and may not be handled✓ Answer
- D.The load may be lifted because the clamp's own weight adds to the counterweight
Once an attachment is fitted, the governing figure is the derated capacity marked for the truck-and-attachment combination, here 4,200 lb, and 4,600 lb exceeds it. An attachment reduces capacity because its own weight sits ahead of the front axle and it usually pushes the load farther out as well.
Ref QB-NBSSMKSource: 29 CFR 1910.178(a)(5); ANSI/ITSDF B56.1, marking of trucks equipped with front-end attachmentsReport a problem with this question
18. Under 1910.178(o)(4), how must a truck equipped with front-end attachments be operated when it is not carrying a load?
- A.As an empty truck, since no freight is on the attachment at the time
- B.As a partially loaded truck, because the attachment itself is a load✓ Answer
- C.As a fully loaded truck, at the lowest capacity shown on any plate
- D.As an empty truck, but only while travelling in reverse down grades
The rule states that trucks equipped with attachments shall be operated as partially loaded trucks when not handling a load. The attachment's weight hangs ahead of the front axle, so it already creates a forward moment and shifts the combined centre of gravity toward the front of the stability triangle.
Ref QB-9UZXQQSource: 29 CFR 1910.178(o)(4)Report a problem with this question
19. An operator is assigned a truck he has not run before and needs to know its capacity. What does OSHA's stability guidance tell him to do?
- A.Apply the capacity of the same model he ran last week at his previous job
- B.Ask the operator on the next shift what loads the truck has handled before
- C.Estimate it from the counterweight size and the number of mast stages fitted
- D.Check the truck's data plate for the maximum weight at the rated load centre✓ Answer
OSHA's appendix says the operator should always check the data plate to determine the maximum allowable weight at the rated load centre. Capacity is specific to the individual truck, its mast, its attachments and even its battery, so a figure remembered from another machine is not valid for the one in front of you.
Ref QB-RBUS5QSource: 29 CFR 1910.178 Appendix A, A-5.2 (check the data plate)Report a problem with this question
20. A company wants to fit fork extensions that will change the truck's capacity. What does 1910.178(a)(4) require first?
- A.A written risk assessment by the site supervisor kept in the truck's file
- B.Prior written approval from the manufacturer, with plates changed to match✓ Answer
- C.Nothing, provided the load handled stays below the original rated capacity
- D.Approval from the operator's trainer, recorded on the certification form
Modifications or additions that affect capacity or safe operation may not be made without the manufacturer's prior written approval, and the capacity, operation and maintenance instruction plates must then be changed to match. Fork extensions move the load centre outward, so the truck no longer performs to its original plate.
Ref QB-8WKSJPSource: 29 CFR 1910.178(a)(4)Report a problem with this question
21. Why do the powered industrial truck rules have operators travel with the forks low and, where possible, tilted back?
- A.It keeps the combined centre of gravity low and holds the load against the backrest✓ Answer
- B.It keeps the drive tyres cooler by taking weight off the front axle in travel
- C.It lets the mast chains slacken so they wear evenly over the length of a shift
- D.It raises the truck's rated capacity by shortening the distance to the axle
A low load keeps the combined centre of gravity low, so bumps, turns and braking move its line of action far less within the stability triangle, and backward tilt holds the load against the backrest instead of letting it slide forward. Raising the load while travelling does the opposite on both counts.
Ref QB-RDSX5QSource: 29 CFR 1910.178(n)(7)(iii); ANSI/ITSDF B56.1, traveling with the load low and tilted backReport a problem with this question
22. Under 1910.178(o)(6), when may the mast be tilted forward with the load-engaging means elevated?
- A.Whenever the load is within the rated capacity shown on the data plate
- B.Only when picking up or depositing a load over a rack or a stack✓ Answer
- C.Only while the truck is stationary on a firm, level and dry floor
- D.Whenever travelling in reverse so that the load trails behind the truck
Tilting an elevated load forward is prohibited except when picking up or depositing it over a rack or stack. Forward tilt at height throws the combined centre of gravity toward the front of the stability triangle at exactly the moment the load is highest, which is the classic forward tipover.
Ref QB-7W8FDNSource: 29 CFR 1910.178(o)(6)Report a problem with this question
23. Under OSHA 1910.178(n)(7)(i), on grades in excess of 10 percent, a loaded truck must be driven which way?
- A.With the load pointed upgrade, whether climbing or descending✓ Answer
- B.With the load pointed upgrade when climbing and downgrade when descending
- C.With the load pointed downgrade, whether climbing or descending
- D.With the forks facing whichever way gives the operator a clear view
OSHA requires loaded trucks on grades over 10 percent to be driven with the load upgrade in both directions, which means backing down the slope. Pointing the load downhill moves the combined centre of gravity toward the front axle just as gravity is already helping the truck tip forward.
Ref QB-QDEMYNSource: 29 CFR 1910.178(n)(7)(i)Report a problem with this question
24. A loaded rider truck must come down a long ramp. Which practice matches the ANSI/ITSDF B56.1 rules for travelling on grades?
- A.Reverse down the ramp, keeping the load upgrade and travelling straight✓ Answer
- B.Drive down forward slowly with the load upgrade and the mast tilted forward
- C.Turn part way down so the load faces uphill once the truck picks up speed
- D.Drive down forward with the forks raised so the load clears the ramp surface
B56.1 has loaded rider trucks travel with the load upgrade, keeps the load-engaging means raised only enough to clear the surface, and directs operators to travel straight up and down rather than turning on a grade. Descending with the load upgrade therefore means reversing down the ramp, and stopping distance is longer on a grade.
Ref QB-6WV48MSource: ANSI/ITSDF B56.1, traveling on grades (loaded trucks, no turning on grades)Report a problem with this question
25. Which combination most increases the risk of a lateral tipover?
- A.A wide turn taken at low speed with the load low and centred
- B.A sharp turn taken at speed with the load raised and off centre to one side✓ Answer
- C.Straight travel at speed on level ground with the forks lowered
- D.A sharp turn taken at low speed with the load lowered and centred
Speed and a small turning radius both push the combined centre of gravity toward the outside of the turn, a raised load makes that sideways swing larger, and an off-centre load has already moved the centre of gravity toward one side of the triangle. Together they are the standard recipe for a lateral tipover.
Ref QB-PD3ATMSource: 29 CFR 1910.178 Appendix A, A-6 and A-7; ANSI/ITSDF B56.1, warning signs of excessive cornering speedReport a problem with this question
26. A sit-down counterbalanced truck begins to tip sideways. What does B56.1 direct the operator to do?
- A.Jump clear on the side away from the direction of the tipover
- B.Release the controls and reach for the overhead guard to steady up
- C.Step off the back of the truck and move well away from the machine
- D.Stay in the seat, brace, hold on, and lean away from the impact✓ Answer
On a sit-down counterbalanced truck the operator should stay with the truck, hold on firmly, brace the feet and lean away from the point of impact. The overhead guard and the restraint keep the operator inside the survival space, while jumping puts the operator on the ground where the guard lands.
Ref QB-5WHS2KSource: ANSI/ITSDF B56.1, sit-down counterbalanced truck tipover instructionsReport a problem with this question
27. A stand-up rear-entry narrow-aisle truck with an open operator compartment starts to go over the edge of a dock. What does B56.1 direct the operator to do?
- A.Stay inside the compartment and brace hard against the back rest
- B.Hold the steering tiller and lean toward the mast for cover
- C.Set the brake and stay standing until the truck comes to rest
- D.Step off and away from the truck, out of the open compartment✓ Answer
The instruction reverses for stand-up trucks with an open compartment: in an imminent tipover or off-dock event the operator should step off and away from the truck where possible, because the open compartment offers no enclosed survival space. For a non-tipover event such as an imminent collision, the operator stays inside the compartment.
Ref QB-NDQXMKSource: ANSI/ITSDF B56.1, stand-up rear-entry truck tipover and off-dock instructionsReport a problem with this question

1. On a sit-down counterbalanced forklift, the stability triangle is bounded by which three points?

2. A four-wheel counterbalanced forklift is said to have a three-point suspension. What makes that true?

3. A loaded forklift remains stable as long as which condition holds?

4. What happens to the combined centre of gravity of truck and load when the load is raised on the mast?

5. A loaded forklift is driven across the face of a slope rather than straight up or down it. Which way does the combined centre of gravity move?

6. A forklift turns while travelling. Which way does the combined centre of gravity shift?

7. A load makes the load moment slightly larger than the truck's vehicle moment. What does the operator notice first?

8. In the see-saw model of forklift stability, what acts as the fulcrum?

9. In OSHA's stability appendix, the counterweight of a forklift is best described as which of the following?

10. A forklift's vehicle moment about the front axle is 120,000 in-lb. The operator picks up a 4,000 lb load whose centre of gravity sits 33 inches ahead of the front axle. What does comparing the moments predict?

11. What does 'load centre' mean on a forklift data plate?

12. A counterbalanced forklift is rated at 5,000 lb. At what load centre is a truck of that size normally rated?

13. Trucks with rated capacities above 30,000 lb are normally rated at which load centres, and why?

14. A data plate reads 5,000 lb at a 24-inch load centre. A uniformly loaded pallet measures 60 inches from the fork face outward. What is the heaviest it may weigh?

15. A data plate reads 4,000 lb at a 24-inch load centre. A uniformly dense crate measures 64 inches from the fork face outward. What is the most it may weigh?

16. A data plate reads 8,000 lb at a 24-inch load centre. The load centre of the load actually being handled measures 30 inches. What is the maximum weight the truck may carry?

17. A truck is plated at 5,000 lb at a 24-inch load centre. With a carton clamp fitted, its attachment plate reads 4,200 lb at a 24-inch load centre. The operator is asked to move a 4,600 lb load whose centre is 24 inches out. What is correct?

18. Under 1910.178(o)(4), how must a truck equipped with front-end attachments be operated when it is not carrying a load?

19. An operator is assigned a truck he has not run before and needs to know its capacity. What does OSHA's stability guidance tell him to do?

20. A company wants to fit fork extensions that will change the truck's capacity. What does 1910.178(a)(4) require first?

21. Why do the powered industrial truck rules have operators travel with the forks low and, where possible, tilted back?

22. Under 1910.178(o)(6), when may the mast be tilted forward with the load-engaging means elevated?

23. Under OSHA 1910.178(n)(7)(i), on grades in excess of 10 percent, a loaded truck must be driven which way?

24. A loaded rider truck must come down a long ramp. Which practice matches the ANSI/ITSDF B56.1 rules for travelling on grades?

25. Which combination most increases the risk of a lateral tipover?

26. A sit-down counterbalanced truck begins to tip sideways. What does B56.1 direct the operator to do?

27. A stand-up rear-entry narrow-aisle truck with an open operator compartment starts to go over the edge of a dock. What does B56.1 direct the operator to do?

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