IMBA RATING variety of trails with different types of tread surface and levels of difficulty
1 surfaced tread, wide and stable, average trail grade less than 5% – max 10%
2 Easy/Green – surfaced tread, firm and stable, rough terrain average trail grade 5% or less -maximum 15%
3 Medium/Blu –tread surface mostly stable with some variability,
obligatory passages may be present, average trail grade 10% or less up to 15%.
4 Challenging/Red – widely variable surface, unavoidable obstacles of medium size, average trail grade max 15% or greater
5 Difficult/Black – widely variable and unpredictable, unavoidable obstacles , loose rocks strong slopes, 20% or more.
6 Extreme/Orange – rough terrain with unpredictable and avoidable big obstacles, natural single tracks with strong slopes.