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Vehicle & Trail Rating System
Randy Bynum, Dave Rumzie, Kelly Swanson



The Esprit de Four Vehicle & Trail Rating System is designed to provide a better understanding
of the vehicle-equipment that is required to safely travel a trail and the difficulty and risks of
that trail. The Rating System is made up of three components: Vehicle Criteria,
Trail Difficulty, and Trail Hazards. These three
components make-up the information needed to prepare for most trips but should only be taken as
a general guideline as the Vehicle & Trail Rating System does not take into account driver
ability or changes in the trail caused by weather.

The final section of the Vehicle & Trail Rating System provides sample ratings
of several popular trails in Northern California.

The values shown in the Esprit de Four Calendar have been determined using this system.

Vehicle Criteria

The Vehicle Criteria component of the Rating System describes the equipment and specifications
that will most likely be needed to safely complete a trail. A vehicle’s rating can be assessed by
comparing the vehicle to the equipment and accessories listed in each class level shown below.

Class 1
Specifications and equipment: Examples:
No additional equipment or minimum specifications.
Stock 4WD passenger vehicles:

AWD minivans

Subaru Outback
Class 2
Specifications and equipment: Examples:
Additional equipment:

Tow hooks (front & rear)
Stock 4WD trucks and SUV’s:

Chevy S-10

Ford Explorer

Chevy Bronco II

Isuzu Trooper or Rodeo

Suzuki Samurai or Sidekick
Class 3
Specifications and equipment: Examples:
Minimum specifications:

Clearance: 7"

Gearing:

  manual 25:1 final
automatic 3.73 axles
Tires: 31"

Additional equipment:

Hand tools to fit vehicle
Stock to slightly-modified:

Jeep Wrangler or Cherokee

Toyota pickup, 4 Runner, or
Land Cruiser

Full-size Chevy pickup or Blazer

Full-size Ford pickup or Bronco
Class 4
Specifications and equipment: Examples:
Minimum specifications:

Clearance: 9"

Gearing:

  manual 40:1 final
automatic 4.10 axles
Tires: 31"

Additional equipment:

One locking-differential

Full roll cage

Suspension/Body Lift: 2.5"
Highly-modified:

Jeep CJ5, CJ7, Wrangler

Scout

Early Bronco

Toyota Pickup or Land Cruiser
Class 5
Specifications and equipment: Examples:
Additional equipment:

Tires: 33"
Same as Class 4
Class 6
Specifications and equipment: Examples:
Additional equipment:

Vehicle-mounted winch
Same as Class 5

NOTES:

  1. Mandatory equipment: fire extinguisher, first aid kit, tires in good condition, brakes & engine in good working order, good and usable spare tire, all antennas less then 54" in height.
  2. Each vehicle class includes everything in all previous classes.

Trail Difficulty

The Trail Difficulty component of the Rating System describes the challenges found on a trail and is a general indication of the skill required to safely complete the trail. Use this section to get a better understanding of the terrain of a trail.

  1. Paved road with pot holes.
  2. Dirt road with washboard.
  3. Dirt road with steep hills, some rocks.
  4. Dirt/rock trail with small-medium rocks, steep hills.
  5. Large scattered rocks, loose soil, up to 10° off-camber.
  6. Large rock piles, steep sandy switch backs with rocks, narrow trails.
  7. Stair steps (1′ tall steps), 15° off-camber.
  8. Very steep loose hills, stair steps (1-2′ tall steps), 20° off-camber.
  9. Long steep climbs, loose silt, large rocks throughout trail, 25° off-camber.
  10. Impassable without winching.

NOTES:

  1. Each successive category may include components of any level preceding it.
  2. Class 7 trails and above also require the following equipment: bottle jack or Hi-Lift jack, tow strap, CB radio, 6′ of chain capable of pulling a vehicle, shovel, bucket, road flares, spare oil & filter, misc. spares (i.e., fuel line, heater hose, filters, and spark plugs) and fluids (brake fluid, gear oil, and coolant), spare gasoline, radiator sealant, and a knowledge of vehicle mechanics. Members must be self-contained and capable of carrying all of their own supplies (i.e., blanket, water (1 gal/day/person minimum).

Trail Hazards

The Trail Hazard component of the Rating System describes the risk of injury inherent in attempting a trail. Use this section to get a better understanding of the risks associated with a trail.

  1. Highway driving (Normal risk of rolling vehicle).
  2. Minimal danger of rolling due to relatively flat wide trails. Good traction.
  3. Some narrowing or trails, steeper climbs, reduced traction.
  4. Moderate risk of rolling from off-camber passes. Moderate climbs and descents. Reduced traction.
  5. Increased risk of rolling due to off-camber and narrow trails. Traction limited in some places.
  6. High risk of rolling due to steep cliffs, loose sandy terrain, steep hills. Traction limited.
  7. High risk of rolling due to steeper hills, very narrow cliff-side trails.
  8. Very high risk of rolling due to extremely narrow trails at edge of a cliff.
  9. Likely rollover with any highly lifted vehicle. Considerable off-camber in multiple directions.
  10. Extreme off-camber requiring external help to stabilize vehicle.

NOTES:

  1. Each successive category may include components of any level preceding it.

Sample Ratings

NAME VEHICLE DIFFICULTY DANGER NOTES
Rubicon 4 8 6 Steep slabs, rocks & off-camber
Fordyce 4 8 7 Water-crossing can be very deep
Dusy/Ershim 4 8 4  
Swamp Lake 4 9 8  
Hollister Hills SVRA 2 4 4 Steep climbs in loose silt, cliffs along edges of many trails
Mini-Rubicon (HHSVRA) 6 6 3 High-clearance vehicles only
Snake Lake 3 5 3  
Blue Lakes 2 4 3  
Pismo Beach 2 3 8 Steep slopes, vertical walls
Bald Mountain 2 4 3 Some granite stair steps
Frank Raines 2 3 4 Off-camber areas, loose sandy soil
Deer Valley 2 4 4 One steep climb in loose silt/rocks
Brewer Lake 2 3 2  
Barrett Lake 4 8 6  
Suprise Canyon 6 10 8 Slick wet waterfalls
Clear Creek 2 4 3 Loose sand/silt

Copyright 1995, 1996, 1997, 1998, Randy Bynum, Dave Rumzie, Kelly Swanson. All rights reserved.

Copyright statement. This document is a Copyrighted publication. No commercial uses are allowed without the written permission which of one or more of the authors. This document may be shared for the good of the sport of 4 wheeling providing that the document is kept in its full and original form including this Copyright notice. The authors have made this document available as a free service to the 4 wheel drive community without any assumption of liability. Any trail rating value can change from time to time based on use and weather conditions. The authors have no control over trail conditions or the condition of any vehicle. No assessment of driver ability is included nor implied in this document. The entire rating system can only be used as a guideline. It can not be used as a single determining factor as to the ability of any driver to safely negotiate any single vehicle through a given trail. The authors reserve the right to make changes to this document without notice or warning.

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