Trail Rating Scale Reference

Decode trail difficulty ratings across every major system — from trail app numeric scales to USFS road classifications and color codes.

Used by trail apps (Gaia GPS, OnX Offroad, Overlander, motor vehicle forums). The most common rating for recreational 4x4 trails.

1–2

Stock Vehicle

Any AWD / stock 4WD

Gravel roads, two-track, maintained dirt. No obstacles. Appropriate for all-season passenger cars.

e.g. Most forest service roads, graded dirt roads

High Clearance

Stock truck / SUV

Rutted dirt roads, loose gravel, small water crossings. Stock SUV or high-clearance vehicle recommended.

e.g. BLM 2-track, light forest roads

4WD Recommended

4WD with some clearance

Rocky or washed-out sections, moderate inclines, occasional water crossings. 4WD helpful but not always required.

e.g. Easy fire roads, moderate forest trails

4WD Required

4WD required

Consistent rocky terrain, significant inclines, loose surfaces. 4WD low and good clearance required.

e.g. Most moderate off-road trails

Lockers Helpful

4WD + locker or LSD

Technical sections, significant obstacle navigation, off-camber situations. Lockers or skid plates beneficial.

e.g. Rubicon (easier sections), Fordyce

Lockers Required

Built 4WD + lockers

Large rocks, steep ledges, deep ruts, significant flex required. Front and rear lockers strongly recommended. Body damage likely on stock vehicles.

e.g. Moab entry trails (Hell's Revenge easy)

Highly Modified

Heavily modified rig

Major obstacles, extreme articulation required, high-clearance mandatory. Lift, lockers, skid plates, rock sliders minimum.

e.g. Moab moderate trails, Rubicon mid-section

Expert Only

Expert rig + driver

Extreme obstacles, significant risk of rollover or recovery needed. Experienced spotter, recovery equipment, and extensively built rig required.

e.g. Rubicon (hardest), King of the Hammers qualifier trails

Extreme

Purpose-built only

Purpose-built competition vehicles only. Effectively impassable for street-legal vehicles. High probability of damage or rollover.

e.g. Ultra4 race trails, hardest Moab lines

Rough Cross-Reference Between Systems

1–10 Scale	USFS Class	Color	Vehicle
1–2	1–2	Green	Stock SUV / any vehicle
3–4	2–3	Green	High clearance / stock 4WD
5	4	Blue	4WD required
6–7	5	Blue / Black	Built 4WD + lockers
8	6A	Black	Heavily modified
9–10	6A/6B	Double Black	Expert / purpose-built

Important Notes

• Ratings are subjective — conditions change dramatically with weather, season, and erosion. Always check recent trip reports.

• Driver skill matters as much as vehicle build — an expert can navigate a rating 8 in a stock truck; a novice can roll a built rig on a 5.

• The 1–10 scale is not standardized — a "7" on one app may be a "5" on another. Use the vehicle requirement column as a better guide.

• Always carry recovery gear (tow strap, shackles, hi-lift jack) and go with a group on anything above a 5.