A Peterbilt 379 weighs between 15,000-19,000 lbs (6,800-8,600 kg) empty, depending on configuration.

A standard Peterbilt 379 day cab weighs around 15,000-16,500 lbs (6,800-7,500 kg), while a sleeper model ranges from 17,000-19,000 lbs (7,700-8,600 kg). Weight varies by engine size, axle setup, fuel capacity, and additional equipment like sleepers or heavy-duty bumpers.

Key Factors Affecting Weight

  • Cab Type: Day cabs are lighter; sleepers add 1,500-2,500 lbs (680-1,130 kg).
  • Engine: Larger engines (e.g., 600+ hp) increase weight by 500-1,000 lbs (230-450 kg).
  • Axles: Tandem axles add 1,000-1,500 lbs (450-680 kg) vs. single axles.
  • Fuel Tanks: Dual 150-gallon tanks add ~500 lbs (230 kg) when full.
  • Materials: Aluminum frames reduce weight by 500-800 lbs (230-360 kg) vs. steel.

Peterbilt 379 Weight by Configuration

Configuration Empty Weight (lbs) Empty Weight (kg) Notes
Day Cab (Standard) 15,000-16,500 6,800-7,500 Single axle, mid-size engine (400-500 hp).
Day Cab (Heavy-Duty) 16,500-17,500 7,500-7,900 Tandem axles, large engine (500-600 hp).
Sleeper (Mid-Roof, 42") 17,000-18,000 7,700-8,200 Single bunk, standard fuel capacity.
Sleeper (Raised Roof, 72") 18,000-19,000 8,200-8,600 Double bunk, extended fuel tanks.

How to Verify Your Truck's Weight

  1. Check the Door Plate: Manufacturer's weight label (inside driver's door) lists GVWR and axle weights.
  2. Weigh at a CAT Scale: Use certified truck scales for accurate empty/full weights.
  3. Calculate Payload: Subtract empty weight from GVWR (e.g., 80,000 lbs GVWR - 18,000 lbs empty = 62,000 lbs payload).

Weight vs. Legal Limits

  • Single Axle: Max 20,000 lbs (9,100 kg).
  • Tandem Axle: Max 34,000 lbs (15,400 kg).
  • Gross Vehicle Weight (GVW): Typically 80,000 lbs (36,300 kg) for 5-axle combinations.
  • Overweight Fines: Exceeding limits risks $100-$10,000+ per violation, depending on severity.

Reducing Weight for Efficiency

  • Swap steel components (e.g., wheels, fuel tanks) for aluminum or composite.
  • Use single fuel tanks if range allows (saves ~250 lbs/113 kg per tank).
  • Opt for a smaller sleeper (e.g., 36" instead of 72").
  • Remove unnecessary accessories (e.g., toolboxes, spare tire).