Trail Ratings / Legend of Difficulty for Off Road Driving
When trying to describe a trail to someone else, via a write-up, trail description, when trying to compare two trails or when trying to judge the suitability of a vehicle or driver for a particular trail, it can be useful to have a standardized method of rating or describing the difficulty of the trail. There are many systems out there, numeric, alphabetic and even some using symbols that can be used, but we have had good luck with this system. Trail ratings you will see on NWToys.com use this system and we hope that you find it useful.
2WD:
1.0 All-weather high speed paved or graded dirt
or gravel road, regularly maintained, with excellent drainage. 4WD not
needed, even in wet weather. Speeds of over 40 mph can be achieved.
Passenger cars/Rav4 type vehicles acceptable.
1.5
Maintained graded dirt road. 4WD not needed except in wet weather. May
have potholes, dips, and sharp curves. May drain poorly in wet weather.
Speeds of over 10 mph possible. Passenger cars/Rav4 type vehicles can
do, but will have to slow down considerably on washouts, etc., due to
lack of ground clearance. No grades over 10 degrees.
EASY 4WD:
2.0 Unimproved or rarely graded dirt road; 4WD
and/or extra clearance occasionally needed at times, with no special
driving skills required. Passenger cars NOT acceptable, due to
insufficient ground clearance. 2WD & 4WD trucks with stock
clearance are acceptable. Street tires are acceptable. Day runs are
typically 20 miles in length.
2.5
Dirt road graded rarely, if ever. 4WD low range and good clearance
often needed, with some extra care and a bit of driving experience
useful. Suitable for novice drivers. Speeds often under 10 mph. Street
tires are acceptable. 2WD trucks NOT acceptable, due to lack of low
range gears. No grades over 20 degrees.
MODERATE 4WD:
3.0 Ungraded road in difficult terrain, rarely
maintained. 4WD low range and clearance required, with some driving
skill and daring useful. Challenges for novice driver. Suitable for
stock 4WD vehicles. Street tires are not recommended. No 2WD vehicles
due to lack of traction. Speeds often under 5 MPH.
3.5
Road or trail in difficult terrain, probably maintained only by
occasional users. Considerable driving skill and daring needed. Not
recommended for the novice driver. Surface may include wash beds, sand,
cinders, lava rock, snow, mud, water, etc. Vehicles with long front or
rear overhang (beyond the axles) may scrape front or rear bumpers on
wash crossings, etc. Street tires not acceptable. Approaching the limit
of what a capable stock 4WD vehicle (with capable driver) can do. Stock
4WD vehicles usually not recommended. Upgrade to 31" tires, mild lift
(1" or 2"), and rear locker or limited slip is highly desirable.
Equipment failure is usually limited to flat tires. Grades may exceed
20 degrees. Occasional off camber situation may exceed 20 degrees.
Water crossings should be 2 feet or less in depth. Spotting may be
required on the more difficult sections, especially for long, wide
vehicles. Average speed is 3 mph. A day run is typically around 10
miles in length. This is the most common numerical rating given to 4WD
trails. Suitable for mildly modified 4WD vehicles & moderately
experienced drivers.
Difficult 4WD:
4.0 Trail badly eroded. Off camber situations
likely and may exceed 25 degrees. Grades may exceed 25 degrees. Water
crossings can exceed 2 feet in depth. Stock vehicles NOT recommended.
31" tires minimum, (33" preferred), mild lift & hard locker,
(not limited slip), in the rear probably required. Front locker or
limited slip recommended. Speeds often under 3 mph. Spotting probably
required on the more difficult obstacles to avoid body damage.
Recommended for experienced 4WD drivers only. Body damage possible, but
unlikely. More likely on long, and/or wide vehicles. Equipment failure
possible, but unlikely.
4.5
Trail is TOUGH. Big rocks, grades exceeding 30 degrees. Off camber
situations exceeding 30 degrees. Sometimes, but not always, best suited
for short wheel base vehicles. (under 105" wheelbase) 33" tires
minimum, (35" or larger preferred). 2" to 4" of lift and gearing of 40
to 1 (20 to 1 for automatics) or lower in first gear, low range
probably required. Hard locker in the rear and limited slip or hard
locker in the front probably required. Speeds often under 1 mph. A day
run will usually be 1-3 miles in length. Body damage likely, but
usually can be avoided by very careful driving and good spotting.
Typically 10% of the vehicles on these runs will experience major
mechanical failure, i.e., drive line or steering failure. (u-joints,
axles, pitman arm, drag link, tie rods, etc.) Usually, but not always,
these failures are due to improper and insufficiently tested vehicle
modifications or poor (sloppy) driving technique. (Too much gas or
steering pressure) An experienced driver with a properly setup vehicle
can usually avoid most breakage.
Extreme 4WD:
5.0
Trail CANNOT be driven the whole way. Winching is required in at least
one point on the trail. Water crossings may exceed 2-½ feet in depth.
Grades exceeding 40 degrees. The biggest rocks with off camber
situations exceeding 35 degrees. Rollovers possible. Usually only
suitable for short wheel base vehicles (under 105" wheelbase), winch,
33" minimum tires, (35" or larger preferred), 3" to 5" of lift, gearing
of 60 to 1 (30 to 1 for automatics) or lower in first gear, low range,
and hard locker in both front and rear axles probably required. Axle
upgrades highly recommended. Speed continuously under one mph. A day
run is typically one mile in length. These trails are typically very
hard on tires. One spare probably required, two spares recommended.
Plug kit and/or tubes recommended. Tires with sufficient sidewall
protection (Boggers, Swampers, etc.) recommended. 50% or greater chance
of body damage. 50% or greater chance of major mechanical failure.
Breakage is usually due to excessive torque or torque spikes on axles
or steering components. Only experienced (5 years +) drivers with extra
money, parts & energy to repair broken vehicles need apply.