Vehicle Rating Guide

Vehicle Selection: Choosing a vehicle that is appropriate to the terrain being driven is a critical component of successfully negotiating a trail. We have provided a chart of vehicles considered adequate for traveling a specific trail rating.

We are often asked if someone’s vehicle can make a particular trail documented on the site. This is a general assessment of the types of vehicle we consider appropriate for a given rating with an average driver. I am sure that someone has taken a stock “whatever” through the Rubicon Trail, but it is not typical, and can lead to vehicle and trail damage. Forcing a vehicle that is not equipped for a particular trail can cause a lot of damage to the terrain as the driver bashes and spins their way to the end. It is a very personal choice to accept the risk of driving rugged terrain, and we all need to take responsibility for protecting the environment and ensuring that trails stay open for other enthusiasts.

This list is not intended to be comprehensive; if your vehicle is not listed, look for a comparable model. It is also important to note that not all vehicles listed for a particular trail rating can run all trails in that category. For example, a Hummer H1 would struggle to drive the Rubicon Trail (although it has been done), but the vehicle could easily traverse a 3.5 or even 4.0 trail in Moab Utah. Vehicle dimensions are a significant factor in successfully completing a trail. A narrow, SWB vehicle (like an FJ40 Land Cruiser) will always outperform a larger vehicle on a tight, rocky trail, but may struggle on steep hill climbs or tall ledges.

We are always interested in your comments

WARNING: Driving off-highway is an inherently dangerous endeavor, where vehicle damage and personal injury is possible. The following trail rating system is intended only as a guide, and does not replace common sense and personal responsibility. Driving a vehicle that is inappropriate for the trail conditions (not just rating) can not only damage the vehicle, it can also do irreparable damage to the environment.

Rating

Vehicle Description

1.0-

Most passenger cars, mini-vans, etc.

1.5-

Tall wagons and 2wd trucks. All cross-over SUV’s. AWD Preferred:
Hyundai Santa Fe
Subaru Outback
Nissan Murano
Buick Rendezvous
Saturn Vue
Lexus RX330

2.0-

Taller wagons, some 2wd trucks (with traction device), taller AWD SUV’s.:

Honda Pilot
Mitsubishi Endeavor
Toyota Highlander
Ford Explorer
Acura MDX
GMC Envoy / Chevrolet Trailblazer

2.5-

4wd SUV’s and trucks with low range gearing. Some AWD (without low range) SUV’s with traction control system and good ground clearance.

Land Rover Freelander
BMW X5
Isuzu Rodeo
Dodge Durango
Mitsubishi Montero Sport
GMC Canyon
Volvo XC90
GMC Yukon
Toyota Sequoia
Jeep Liberty

3.0-

High clearance SUV’s and trucks with low range gearing. Traction device may be required in some models (noted). Vehicles should not have running boards.

Land Rover Discovery II (with center differential lock)
Land Rover Range Rover
Toyota Land Cruiser / Lexus LX470
Toyota 4runner / Lexus GX470
Mitsubishi Montero (with traction control)
Isuzu Trooper (with G80 limited slip)
VW Touareg (with rear locking differential and air suspension)
Nissan Xterra (with traction control)
MB G-wagon (three locking differentials)

3.5-

Very high clearance SUV’s and trucks with good skid plates, long travel suspension and a locking differential.

Hummer H2
Hummer H1
Toyota Land Cruiser FJ80 (with dual locking differentials)
Jeep Wrangler and Unlimited (with D44 option and limited slip)
Toyota Tacoma (with TRD package and locking differential)

4.0-

There are no production SUV’s or trucks capable of traversing this rating of trail without a very experienced driver, or terrain specific to the capabilities of the vehicle. For example 4.0 rated trails in Moab have been traversed in Hummer H1’s. The Jeep Wrangler Rubicon could be argued for this category as well, but suffers from poor ground clearance (for this trail rating).

 

Important Terms

All Wheel Drive (AWD): All wheel drive vehicles do not typically have low range gearing, and may utilize a viscous coupling unit or electronic or hydraulic clutch packs to distribute power to the front and rear axle. All wheel drive is designed to be driven on all road surfaces, with improved traction on wet and icy roads. The vehicle may have a provision to lock the center differential which improves trail performance by permanently engaging both drive shafts, with power split 50/50 to front and rear axles. AWD is not to be confused with part-time 4wd. Some SUV's (like the Toyota Land Cruiser) have full time AWD, low range gearing for rugged terrain, and a center differential lock for the ideal combination of selections.

Full Size Vehicles: Full size vehicles are classified as having a track width exceeding 65”, and include full size trucks and SUV’s like the Tahoe, Expedition, etc. While these vehicles are very capable and have generous capacities (excellent for expedition travel), they will struggle in tighter trails and will require larger tires to accommodate their poor brake over angle and greater width. A full size vehicle should adjust the trail rating by (.5). For example a trail rated in the expedition guide as 2.5 should be considered a 3.0 for full size vehicles. In addition, the brush rating should be adjusted to the next higher as well.

Limited Slip Differential (LSD): A LSD only "limits" wheel spin to one axle shaft of a differential by utilizing a series of clutches or cone shaped gears. A LSD is a great improvement over an open differential, but does not lock completely and is most effective in sand, mud and loose surfaces. LSD's are least effective in rocky and heavily rutted terrain where tires are likely to leave the ground. Sometimes referred to as Posi-traction.

Locking Differential: A locking differential mechanically engages both axle shafts at the differential carrier, preventing wheel spin to an individual shaft. Both tires will turn at the same speed. Locking differentials can be full-time or driver selectable (like the Toyota Electronic Locker)

Long Wheel Base (LWB): LWB vehicles are classified as having a wheelbase in excess of 120". LWB vehicles will perform well on steep climbs and ledges as the front tires often clear the obstacle before the rear tires need to climb it. LWB vehicles will suffer on tight trails and may require rocker panel protection to prevent body damage.

Part-Time 4wd: Part-time 4wd systems are typically found on trucks and most traditional (body on frame) SUV's. Part-time 4wd systems do not have a center differential, and when engaged should not be driven on dry pavement as the front and rear drive shafts are mechanically engaged, and lock power front and rear equally. There is no differentiation to allow for smooth turning on pavement.

Short Wheel Base (SWB): SWB vehicles are classified as having a wheelbase of less than 100". SWB vehicles perform well in tight, rocky terrain. SWB vehicles will also be less stable on steep climbs and ledges.

Traction Control: Traction control is an electronic system utilized to limit individual wheel spin by applying brake pressure to the wheel to slow it down, and reapply power to the stationary tire. They use signals from sensors at the wheel hub to determine wheel speed, and a series of complex algorithms to compute the amount of brake pressure required. These systems are marginally effective, although a great improvement over open differentials.

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