KTM Adventure Tours has a useful description of rider skill levels for both road and dirt. They are presented here as a suggested evaluation criteria for rider skill level and trail difficulty classification. (Thanks to KTM Adventure Tours for this outline. A very interesting site, by the way; makes me want to go.)
Level 1
Offroad: Gravel roads and field trails, alternating with single tracks. Without steep ascents or descents, and with the occasional detour on tarmac roads to pass off-road segments that are too extreme. Challenging and achievable!
Street: You have at least one season of riding experience; your personal style is still developing. You are able to perform leans of up to 30 degrees, braking is usually concluded before the turn. You are able to perform the emergency full braking maneuver and fast swerves. You are uncertain riding in the rain.
Level 2
Offroad: Gravel roads with washouts and potholes, eroded open trails with occasional deep ruts, firebreaks, dried-up riverbeds, simple river crossings, single tracks without extreme ascents or descents.
Street: You have at least two seasons or 6,000 miles of motorcycle riding experience. Loose, smooth riding style with sufficient reserves. Correct curve approaches, round lines. Assured sight lines, classic cornering style with both knees on the fuel tank, safe judgment regarding overtaking procedures. Your personal riding style has begun to develop.
Level 3
Offroad: Deeply rutted gravel roads, eroded open trails with water holes, single trails with tight turns as well as extreme ascents and descents, demanding river and stream crossings. In between, longer, simpler sections.
Street: You are able to perform leans of up to 40 degrees; defensive but rounded riding style in the rain. You have a command of various cornering styles (classic, pressing down from above, slightly hanging off the bike), the proper approach to curve combinations, effective braking, and steering and acceleration points. Hazards are recognized and resolved as soon as possible.
Level 4
Offroad: Rock ledges, loose rubble, deep sand, ruts, slippery surfaces: in combination with steep ascents or descents. Also on the itinerary: mud holes, steep slopes, slope traverses and passages that require courage and a cool head – a fast-riding tour with many challenges that must be overcome!
Street: Your individual style permits nearly full use of the tire traction, even in banked or off-camber corners, always with the necessary reserves. Uphill and downhill curves, including tight hairpins, are rounded quickly and smoothly. Your choice of riding lines is always assured, reserves are available if there’s mud on the road surface…
Level 5
Offroad: The most difficult off-road segments will be ridden in every kind of weather, even in rain or high temperatures. Due to the generally high level of difficulty, this level lacks longer, easier segments and the swift pace makes great demands on the riders’ physical fitness. The group truly needs team spirit to get through the tour.
Street: You have racing experience at the hobby-racer level, over 30,000 miles of motorcycle experience. You have practically the full use of the tire grip, even in the rain. Braking into the corners, short coasting phase, gentle weight shifts, early acceleration. Very quick riding style even in blind corner combinations.
