Trail Difficulty Is More Than a Number
A trail rating describes the hardest unavoidable part of a route—not the average mile. Learn what the obstacles look like, what makes them worse, and why the same trail can feel completely different in two vehicles.
Read the Rating Correctly
Every AGF rating is set by the hardest obstacle you cannot reasonably bypass in normal, dry conditions. A mostly easy road can still earn a higher number because of one shelf, climb, ledge or water crossing.
Maintained / Easy
Maintained gravel or smooth dirt; minor washboard and shallow potholes.
- Rig
- Passenger vehicle where legally allowed; 4x4 not normally needed
- Tires
- Street or all-terrain
- Lockers
- None
- Recovery
- Normal roadside kit
The line: No meaningful unavoidable obstacle.
Rough Road
Rough gravel, potholes, washboard, small rocks or shallow ruts.
- Rig
- AWD or similar; a stock 4x4 is easily capable
- Tires
- All-terrain preferred
- Lockers
- None
- Recovery
- Basic recovery gear recommended
The line: Manageable without careful tire placement.
Easy High-Clearance
Mild rocks, erosion, shallow crossings, modest ruts or loose grades.
- Rig
- Stock high-clearance 4x4
- Tires
- Stock-size all-terrain
- Lockers
- None
- Recovery
- Basic recovery gear
The line: Line choice may help; traction aids are unnecessary in normal conditions.
Moderate
Noticeable rocks, deeper ruts, moderate climbs, uneven crossings or mild off-camber terrain.
- Rig
- High-clearance 4x4; low range strongly preferred
- Tires
- 31-inch class or capable stock fitment
- Lockers
- None normally
- Recovery
- Rated recovery points and basic recovery gear
The line: A stock 4x4 can pass with deliberate line choice in normal conditions.
Moderate 4x4
Repeated rocks or ruts, moderate ledges, loose climbs, meaningful articulation or water hazards.
- Rig
- True 4WD with low range and a competent driver
- Tires
- 31–33-inch all-terrain or mud-terrain
- Lockers
- Helpful, not normally required
- Recovery
- Full basic recovery kit; travel partner recommended
The line: Tests clearance, traction or articulation, but suits a prepared stock-to-mild rig.
Difficult
Larger rocks, ledges, deep ruts, steep loose grades, significant water or sustained technical sections.
- Rig
- Modified 4x4; experienced driver
- Tires
- 33-inch class recommended
- Lockers
- Rear locker recommended
- Recovery
- Winch or capable partner strongly recommended
The line: A stock rig may get stuck or damaged at the hardest unavoidable obstacle.
Very Difficult
Significant ledges, boulder fields, severe articulation, steep technical climbs or restricted line choice.
- Rig
- Well-prepared modified 4x4
- Tires
- 33–35-inch class
- Lockers
- At least one; dual lockers often help
- Recovery
- Winch, recovery kit and capable partner expected
The line: Needs traction aids, real clearance or precise technical driving.
Advanced
Serious technical terrain, large ledges, deep holes, major off-camber sections or several high-consequence obstacles.
- Rig
- Purpose-prepared trail rig; advanced driver
- Tires
- 35-inch or larger
- Lockers
- Dual lockers strongly recommended
- Recovery
- Winch and redundant recovery expected
The line: Breakage or body damage is plausible even in a capable vehicle.
Extreme
Major boulders, severe ledges, extreme climbs, deep mud or water, or highly consequential terrain.
- Rig
- Highly modified or purpose-built 4x4
- Tires
- 35–37-inch or larger
- Lockers
- Dual lockers expected
- Recovery
- Winch, spotters, recovery team and spare parts
The line: Substantial damage, rollover or immobilization is a real risk.
Expert / Extreme
Competition-grade or near-competition obstacles with exceptional consequence and little or no bypass.
- Rig
- Purpose-built 4x4; expert driver
- Tires
- 37-inch-plus
- Lockers
- Dual lockers and specialized drivetrain
- Recovery
- Full recovery team, winches, spotters and a contingency plan
The line: Unsuitable for ordinary recreational 4x4s.
How AGF sets the number
- Hardest unavoidable obstacle. The rating comes from the toughest spot you cannot reasonably bypass, not the average mile.
- Normal conditions. Snow, runoff, mud, erosion, deadfall and reroutes are reported separately as condition notes.
- Required vs. recommended. Vehicle guidance separates what you need from what only adds margin.
- Every number is explained. Each trail lists its limiting obstacle and how confident the rating is.
- Official access always wins. A rating never overrides closures, motor vehicle use maps, land-manager rules, private property or posted signs.
That was the old four-step system. Old classes are never converted automatically; every trail is re-rated against this scale. Until a route is re-rated, read old Class 1 as roughly 1–3, Class 2 as 3–5, Class 3 as 5–7 and Class 4 as 7–10, and treat that as a rough guide only.
What the Trail Actually Looks Like
Every photo is a Land Cruiser on a Montana trail, shot on 406 Cruisers club runs. Use them to recognize the obstacle category, then evaluate its height, depth, slope, exposure, surface and available bypasses.
Graded Dirt Road
A broad, maintained surface with drainage, shoulders and enough width for normal traffic. It can still include washboard, dust and potholes.
Difficulty jumps when: rain softens the road, potholes hide sharp edges, washboard reduces control or snow blocks the crown.
Embedded Rock
Rock fixed into the roadbed rather than loose on top. The tire must climb it or the vehicle must straddle it without striking the differential or belly.
Difficulty jumps when: the rock is taller than axle clearance, angled toward a sidewall or positioned where there is no clean line.
Shelf Road
A narrow route cut into a hillside with a bank on one side and a drop on the other. Technical difficulty may be modest while consequences are high.
Difficulty jumps when: the road narrows, the outside edge crumbles, oncoming traffic appears or the driver cannot see the outside tire.
Off-Camber Section
The road tilts sideways, shifting weight toward the downhill tires. The vehicle may feel worse than the actual angle, but soft edges and tall loads matter.
Difficulty jumps when: the downhill side is soft, a rut increases lean, the vehicle is top-heavy or the line also climbs or turns.
Cross-Axle Obstacle
Opposite wheels compress while the other pair unloads. An open differential may send power to the tires with the least traction.
Difficulty jumps when: suspension travel runs out, a wheel lifts, the obstacle is on a climb or momentum would create a hard landing.
Deep Rut
Parallel trenches force the vehicle to ride inside the rut or balance on its edges. The center ridge can contact differentials, exhaust or skid plates.
Difficulty jumps when: the rut is deeper than axle clearance, the sides collapse, steering cannot climb out or water hides the bottom.
Water Crossing
Moving or standing water can hide holes, rocks, soft sediment and a damaged exit. Current can move a vehicle before water reaches the intake.
Difficulty jumps when: water is fast, visibility is poor, the bottom is soft, the exit is steep or depth approaches vulnerable components.
Mud
Mud ranges from a thin slick layer to deep suction. Tire tread, vehicle weight and the firmness below the surface matter more than color alone.
Difficulty jumps when: ruts swallow axles, the base disappears, the route slopes sideways or repeated traffic turns the exit into a wall.
Loose Climb
A grade covered in gravel, shale, sand or loose rock. Tires dig and move the surface instead of pushing against a firm roadbed.
Difficulty jumps when: the climb steepens, there is a turn, wheelspin creates holes or stopping leaves no safe restart.
Turnaround Limitations
A dead end, blocked route or failed obstacle becomes serious when the trail is too narrow to turn around. Reversing may be the only exit.
Difficulty jumps when: wheelbase is long, visibility is poor, trailers are involved, the edge is exposed or multiple vehicles must reverse.
Why the Same Trail Feels Different
No single modification defines a capable vehicle. Geometry, traction, durability, weight, driver judgment and trail conditions work together.
Wheelbase
A shorter wheelbase turns tighter and usually improves breakover angle. A longer wheelbase can bridge holes and feel more stable, but it needs more room and may drag its belly over crests.
Clearance
Look beyond the rocker panel. Differential clearance, belly height, approach angle, departure angle and breakover angle determine what actually contacts the terrain.
Tire Size
Larger tires improve obstacle rollover and raise axle clearance. The gain under the differential is only half the increase in tire diameter, and added size can strain gearing, steering and brakes.
Lockers
A locker keeps both wheels on an axle driving when one unloads. It can turn a wheel-lifting obstacle from a momentum problem into a controlled crawl—but it cannot create grip on every surface.
Driver Experience
Good drivers read terrain early, place tires deliberately, use low range smoothly, know when to spot and turn around before a small problem becomes a recovery.
Weight + Load
Roof tents, tools, water and spare parts change braking, suspension travel and center of gravity. A heavily loaded build may have less usable clearance and more off-camber risk.
Vehicle Setup Changes the Margin
Limited Margin
- Long overhangs and low underbody components
- Road-focused tires may struggle on rock or mud
- Electronic traction aids need wheelspin to react
Useful Baseline
- Low range and better geometry improve control
- Factory tires and steps may still be vulnerable
- Driver line choice remains the deciding factor
More Margin, Not Immunity
- Larger tires, lockers and armor expand options
- Extra weight and height create new limitations
- A bad line can still break expensive parts
The Thirty-Second Field Check
Stop before the obstacle, get out and inspect it. The best recovery is the decision that prevents the vehicle from becoming stuck or damaged.
Look For
- The highest point, deepest hole and softest edge
- A tire line that protects differentials, rocker panels and sidewalls
- Where the vehicle will lean, unload a tire or lose visibility
- A safe place to stop, reverse or winch if the attempt fails
- Whether the obstacle continues around a blind corner
- Room for every vehicle in the group—not just the lead rig