CFA Stability Triangle & Tip-Over Prevention 2 — Questions and Answers
Question 1: Where is the center of gravity of an unloaded counterbalanced forklift typically located?
- At the tip of the forks
- Above the rear axle only
- Within the machine frame between front and rear axles (Correct answer)
- At the top of the mast
Correct answer: Within the machine frame between front and rear axles
The unloaded forklift's center of gravity sits within the machine frame, held behind the front axle by the heavy counterweight at the rear.
Question 2: When a load is placed on the forks, the combined center of gravity shifts:
- Toward the rear of the forklift
- Downward toward the ground
- Forward toward the load (Correct answer)
- Upward along the mast
Correct answer: Forward toward the load
Adding a load shifts the combined center of gravity forward toward the load, which is why exceeding rated capacity risks tipping the forklift forward over the front axle.
Question 3: When traveling downhill with a load, the operator should:
- Travel forward with the load facing downhill
- Travel in reverse with the load facing uphill (Correct answer)
- Travel forward with the load facing uphill
- Travel sideways across the grade
Correct answer: Travel in reverse with the load facing uphill
On a downhill grade with a load, the operator should travel in reverse so the load faces uphill, keeping the heavy load on the uphill side to maintain stability and prevent forward tip-over.
Question 4: How do under-inflated or worn tires affect the stability triangle?
- They enlarge the effective stability triangle
- They have no effect on stability
- They reduce the effective support base and increase tip-over risk (Correct answer)
- They shift the center of gravity rearward
Correct answer: They reduce the effective support base and increase tip-over risk
Worn or under-inflated tires compress unevenly and reduce effective contact area, shrinking the real support base and making tip-overs more likely than the design intended.
Question 5: A forklift rated at 5,000 lbs becomes unstable when:
- Carrying any load over 3,500 lbs regardless of position
- The load causes the combined center of gravity to exit the stability triangle (Correct answer)
- Traveling faster than 5 mph with any load
- The load width exceeds the fork spread
Correct answer: The load causes the combined center of gravity to exit the stability triangle
Rated capacity is defined at a specific load center; real instability occurs when the combined center of gravity moves outside the stability triangle, which depends on both weight and load center distance.
Question 6: Why should forks be kept 4–6 inches off the ground during travel?
- To reduce tire wear on the drive axle
- To keep the combined center of gravity low and maximize stability (Correct answer)
- To comply with posted speed limit signs
- To prevent damage to the fork tines
Correct answer: To keep the combined center of gravity low and maximize stability
Keeping forks low during travel keeps the combined center of gravity as low as possible, maximizing the margin before it could exit the stability triangle.
Question 7: How do wet or oily floor surfaces primarily affect forklift stability?
- They enlarge the effective stability triangle
- They reduce traction, allowing sudden lateral shifts that move the center of gravity outside the triangle (Correct answer)
- They increase the load capacity rating
- They have no effect on the stability triangle geometry
Correct answer: They reduce traction, allowing sudden lateral shifts that move the center of gravity outside the triangle
Slippery floors reduce traction and can cause sudden lateral slides, rapidly shifting the center of gravity outside the stability triangle even at low speeds.
CFA Stability Triangle & Tip-Over Prevention 2
Where is the center of gravity of an unloaded counterbalanced forklift typically located?