| Easiest | Easy | More Difficult | Very Difficult | Extremely Difficult | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
| White Circle | Green Circle | Blue Square | Black Diamond | Double Black Diamond | ||||||
| l | l | n | u | uu | ||||||
| Overall Difficulty Score | Up to 5 | 5 - 10 | 11 - 15 | 16-20 | Over 20 | |||||
| Trail Grade (Steepness - refers to any section > 0.4 mile) | 1 Ave up to 2%, Max 10% | 2 Ave up to 5%, Max 10% | 3 Ave up to 5%, Max to 15% | 4 Ave up to 7.5%, Max > 15% | 5 Ave up to 10%, Max > 15% | 6 Ave to 12.5% | 7 Ave to 15% | 8 Ave to 17.5% | 9 Ave to 20% | 10 Ave over 20% |
| Altitude | Under 4000 ft | Under 4000 ft | Under 6000 ft | Under 8000 ft | Over 8000 ft | |||||
| Feet of Climb | Under 1000 | Under 1500 | Under 2500 | Under 4000 | Over 4000 | |||||
| Length | Under 10 Mi | Under 15 Mi | Under 20 Mi | Under 30 Mi | Over 30 mi | |||||
| Trail Difficulty | 1 Paved or Gravel Bike Path closed to vehicle traffic | 2 Paved or Gravel Road open to vehicle traffic | 3 Dirt Road or Narrow Path with small hazards up to 2 inches | 4 Dirt Road or Narrow path > 3 ft wide with exposed but stationary hazards up to 8 inches such as roots, ruts, drops, or streams | 5 Single Track as little as 2 ft wide with stationary hazards up to 8 inches | 6 Single track as little as 1 ft wide with exposed but stationary hazards up to 15 inches such as roots, ruts, drops, or streams | 7 Single track as little as 1 ft wide with stationary and unstable hazards up to 15 inches such as loose rocks, slick roots, sand, ruts, drops, or streams | 8 Single track with stationary and unstable hazards over 15 inches such as loose rocks, slick roots, sand, ruts, drops, or streams | 9 Same as 8 with un-avoidable jumps or drops that require dismount | 10 Same as 8 with streams that require wading |
| Surface | Paved or hardened | Firm and Stable | Mostly Stable | Widely variable | Widely variable and unpredictable | |||||
| Trail Width | 6 ft or more | 3 ft or more | 2 ft or more | 1 foot or more | Less than 1 ft | |||||
| Unavoidable Obstacles | None | > 2 in high | < 8 in high | <15 in high | >15 in high | |||||
| Bridges | > 36 in wide | > 36 in wide | >24” wide | >24” wide | < 24” wide | |||||
| Technical Trail Features | None | None | < 24” high, Width > ½ height | <48” high, Width > ½ height | >48” high | |||||
Overall Trail Rating score:
(Steepness rating x 2) + Technical difficulty rating + 1/4 point for every mile of total length over 15 + 1/4 point for every 250 feet of total climb over 1500
- Example. Montebello – Medium Ride
- Steepness rating: 4 (More Difficult)
- Technical Difficulty rating: 7 (Very Difficult)
- Total feet of climb: 1850 feet (More Difficult)
- Length: 18 miles (More Difficult)
Overall Technical difficulty is Very Difficult because of the technical difficulty rating, even though Steepness, Total Climb, and length are all rated More Difficult. Numeric difficulty score is: (4 x 2) + 7 + (1850-1500)/250*0.25 + (18-15)*.25 = 16.1
Also, routes with a difficulty score of 16-20 are considered Very Difficult.