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How to Identify and Grade Trails


Difficulty Rating

IMBA have a very nice page on grades of trail difficulty. It's handy to be familiar with this when trying to describe trails or to use as a guide when deciding if a particular trail is suitable for your skill level.

A summary table is this:

Easiest
White Circle

Easy
Green Circle

More Difficult
Blue Square

Very Difficult
Black Diamond

Extremely Difficult
Double Black Diamond

Trail Width 2.1m or more 90cm or more 60cm or more 30cm or more 15cm or more
Tread Surface Hardened or surfaced Firm and stable Mostly stable with some variability Widely variable Widely variable and unpredictable
Average Trail Grade Less than 5% 5% or less 10% or less 15% or less 20% or more
Maximum Trail Grade Max 10% Max 15% Max 15% or greater Max 15% or greater Max 15% or greater
Natural Obstacles and Trail Technical Features (TTFs) None

Unavoidable obstacles 5cm tall or less

Unavoidable obstacles 20cm tall or less

Unavoidable obstacles 38cm tall or less

Unavoidable obstacles 38cm tall or greater

 

Avoidable obstacles may be present

Avoidable obstacles may be present

Avoidable obstacles may be present

Avoidable obstacles may be present

     

May include loose rocks

May include loose rocks

 

Unavoidable bridges 90cm or wider

Unavoidable bridges 60cm or wider

Unavoidable bridges 60cm or wider

Unavoidable bridges 60cm or narrower

   

TTF's 60cm high or less, width of deck less than 1/2 the height

TTF's 1.2m high or less, width of deck less than 1/2 the height

TTF's 1.2m high or greater, width of deck is unpredictable

     

Short sections may exceed criteria

Many sections may exceed criteria

Full page here:

http://www.imba.com/resources/trail_building/itn...

Here's a few examples of what to expect on each level of trail.

White

As this is defined as a track a vehicle could fit down it would have to be firetrail. Also note that these trails should not have any sections over 10% grade and should be smooth (eg. have no drops or roll-offs). Eg:

Left Avoiding Walking Downhill Freeway Evas Junction

Green

Narrower or steeper or with some unavoidable drops of up to 5cm - equivalent of riding up or off the average kerb. Eg:

Halfway Corner Straight

Blue

Again, narrower and steeper and with larger unavoidable drops/steps of up to 20cm. Eg:

Bear Right Step Up Careful

Black

Unavoidable obstacles of up to 38cm - like riding up or off a low sofa. Eg:

Oxford Falls Squidly Rolling John

Double Black

Unavoidable obstacles of over 38cm. A double black run is most likely to be incredibly steep, technical, with loose surface or all of the above. Eg:

Steve mid-air Flying Wilson Flying Gazza Mountain Goat Matt.

Track Type

On our site we also talk about types of trail. Here's a quick idea of what we mean by the these:

Single Track - Enclosed

Single track is pretty obvious - a trail only wide enough to ride single file.

The enclosed type is bordered at both sides by vegetation or rocks or fences or something. This type of trail is a rider's dream! Smiling

Both varieties of single track are also referred to as 'sniggle' (a term that allegedly originates from the MTB-OZ mailing list and a common typo for the work single).

Great Wall Rolling Sniggle Majura Sniggle Royal Single Track

Single Track - Open

Still too narrow to ride anything but single file, but out in the open (with nothing to crash into normally).

Sparrow Open Sniggle Ditty Jump

Double Track

Wide enough to ride side by side (and often to drive on), but not a full on fire trail or 4WD road (ie. not graded or with a centre line of grass/rocks/etc.).

Lush Double Track Polblue Trail Cascade Trail On the Cascade Trail

Firetrail

Trail wide enough to drive a vehicle on with no centre divide. To MTB riders there's no real difference between a firetrail (built by the fire services for access and protection) and other 4WD tracks or forest roads so we classify them all under the same thing here.

Gulp Road Water Bar Madness Junction on Hill Topping Out

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