Dock Leveler Ramp Slope and Truck Bed Range
Separates whether a leveler can reach a trailer bed from whether equipment can work across the ramp once it does.
Example
You enter
- Dock height (in) 48
- Lowest trailer bed height (in) 40
- Highest trailer bed height (in) 56
- Leveler length (ft) 6
- Rated service range above and below (in) 12
- Practical grade guideline (%) 10
- Longer leveler considered (ft) 10
- Outlier trailer bed height (in) 36
You get
- Lowest trailer 8
- Outlier differential (in) 12
- Grade at the low trailer 11.1% -- OVER the guideline
- Outlier grade (%) 16.6667
- On the longer leveler 6.66667
- Outlier longer grade (%) 10
- Governing grade 16.6667
No published worked example is on file for this calculation. It is checked against a hand-worked derivation of its method and an independent reference test.
Details, formula, and sources
ScopeThe worked 6 ft leveler is well inside its service range at 11.1% grade, over the 10% guideline; a 10 ft leveler brings it to 6.7%. Manufacturer service range governs.
Formula or tableDifferential = dock height - trailer bed height; ramp grade = differential / leveler length.
Source and editionThe leveler manufacturer's rated service range above and below dock level, and the employer's powered-industrial-truck program.
Free accessThe geometry is public; service range and rated capacity come from each manufacturer's published data.
What governsEstimate. AHJ and licensed professional govern.
API field namesdock_height_in, low_bed_height_in, high_bed_height_in, leveler_length_ft, service_range_in, grade_guideline_pct, longer_leveler_length_ft, outlier_bed_height_in, low_differential_in, outlier_differential_in, low_grade_pct, outlier_grade_pct, longer_leveler_grade_pct, outlier_longer_grade_pct, governing_grade_pct
- Nominal length grade here is rise over the NOMINAL deck; manufacturers' charts use the shorter working length, so read about 20% steeper on a 6 ft leveler (the working length is about 17% shorter; Poweramp: 8 in on 6 ft = 13.3%, on 10 ft = 7.6%). Limits differ by truck: hand pallet 3%, powered pallet 7%, electric fork 10%, gas fork 15%Poweramp Grade Chart for Dock Levelers
- Grade guideline roughly 10% a common practical maximum for powered equipment, 7% or less preferred; a manual pallet truck struggles well before a forklift doesindustry practice, entered as an input
- Static geometry a trailer settles as it loads, rises as it empties, and can creep away from the dock; restraints and chocks address the creepspec-v1814 scope