Oregon Weight Limitations and Axle Spacing Rules

Nov. 14, 2025, 4:40 p.m.
Oregon regulates truck weights to protect roadways, bridges, and overall traffic safety. These rules determine how much weight a vehicle can legally carry and how far apart its axles must be to distribute weight safely. Carriers must follow both statutory weight limits and axle spacing requirements, especially when applying for oversize/overweight (OS/OW) permits.
Oregon Weight Limitations

1. Oregon Maximum Legal Weight Limits (Without Permit)

A. Axle Weight Limits

  • Single axle: Up to 20,000 lbs

  • Tandem axle: Up to 34,000 lbs

  • Tridem axle: Usually 48,000–51,000 lbs depending on spacing and configuration

  • Steer axle: Typically 12,000–20,000 lbs, depending on manufacturer’s rating

B. Gross Vehicle Weight (GVW)

Oregon uses both:

  • The Bridge Formula, and

  • State-specific weight tables

The legal maximum gross weight generally caps at 105,500 lbs, but only when operating under an ODOT divisible load permit.
Without a permit, the usual maximum GVW is 80,000 lbs.

2. Axle Spacing Rules in Oregon

Axle spacing determines how much weight a truck can carry across the entire vehicle. The more distance between axles, the more weight is allowed.

Key concepts:

A. Bridge Formula (Federal + Oregon application)

Oregon applies a version of the Federal Bridge Weight Formula to prevent excessive stress on bridges.
It calculates weight based on:

  • Number of axles

  • Distance between axle groups (wheelbase)

  • Load distribution

Longer spacing = Higher allowable weight.

B. Group Axle Spacing

Oregon measures spacing between:

  • Steer axle to the first drive axle

  • Drive to trailer axles

  • Trailer axle groups
    These measurements determine group weight limits under both legal operation and permit operation.

C. Wheelbase Requirements for 105,500 lbs

To operate at the higher Oregon limit (with permit), trucks must meet a minimum 51-foot wheelbase between the first and last axle.

3. Permit Requirements for Exceeding Standard Limits

A. Divisible Load Permits

Required when:

  • GVW exceeds 80,000 lbs up to 105,500 lbs

  • Axle groups exceed legal limits but comply with Oregon weight tables

B. Non-Divisible Load Permits

Used for:

  • Heavy equipment

  • Specialized machinery

  • Loads that cannot be broken down

These permits may override some spacing restrictions but still follow strict safety formulas.

4. Enforcement & Penalties

ODOT enforces weight rules through:

  • Weigh stations

  • Mobile enforcement units

  • Roadside inspections

Penalties for overweight operation include:

  • Fines based on pounds overweight

  • Possible permit revocation

  • Delayed travel or mandatory load adjustments

5. Why Axle Spacing Matters in Oregon

Oregon allows heavier weights than many states (105,500 lbs vs. typical 80,000 lbs), but only when:

  • Axle spacing meets state charts

  • Vehicles follow the bridge formula

  • A valid ODOT permit is held

This makes Oregon’s system more flexible, but also more technical, requiring precise measurements and correct permit classification.