Haul-Road Total Resistance and Required Rimpull
The resistance a loaded hauler fights and the rimpull to climb it.
Example
You enter
- Gross vehicle weight, loaded (lb) 150000
- Road grade (%, negative downhill) 5
- Rolling resistance (%) 4
You get
- Total resistance 9
- Required rimpull 13500
- Rimpull per ton (lb) 180
Details, formula, and sources
total resistance = grade + rolling resistance; rimpull = total x GVW (20 lb/ton per 1%). A 150,000 lb hauler on a 5% grade over a 4% rolling-resistance road fights 9% and needs 13,500 lb of rimpull (180 lb/ton). Downhill the resistance goes negative and the operator is on the retarder. Grading the road down cuts rolling resistance - the cheapest horsepower there is.
total_resistance_pct = grade_pct + rolling_resistance_pct; required_rimpull_lb = total_resistance_pct / 100 x gvw_lb; rimpull_per_ton_lb = 20 x total_resistance_pct.
Haul-road resistance identity by name (total = grade + rolling; rimpull = total x GVW; 20 lb/ton per 1%); first-principles tractive-effort statics.
The resistance statics are public first-principles; the available rimpull in gear comes from the manufacturer's rimpull-speed curve.
Estimate. AHJ and licensed professional govern.
Field names used by the API: gvw_lb, grade_pct, rolling_resistance_pct, total_resistance_pct, required_rimpull_lb, rimpull_per_ton_lb
- Rolling resistance ~2% for a hard maintained haul road, 10%+ for soft or rutted ground (~4% default)Caterpillar Performance Handbook
- Rimpull rule 20 lb/ton per 1% of total resistance; required rimpull = total resistance x GVWfirst-principles tractive effort