CTC off-road trail grades

A grading system for way-marked off-road cycling trails has been adopted in the UK, and is used by official bodies such as Forestry England and IMBA-UK. It was originally developed by Cyclists' Touring Club (CTC) employee Colin Palmer in June 1999, based on a system widely used for grading cross-country skiing routes.

A solitary major hazard (e.g. one steep hill or a difficult junction) will not necessarily raise an otherwise 'Easy' route into a 'Difficult' one.

Severe

 * The Forest of Ae: Ae Downhill Course (part of 7stanes project)
 * Afan Forest Park: Skyline Trail
 * Ampthill Forest: Dual slalom Downhill Course
 * Coed-y-Brenin: Red Bull Trail and Karrimor Trail
 * Cwmcarn: Y Mynydd Mojo
 * Dalby Forest
 * Glentress Forest: V-Trail
 * Guisborough Forest
 * Hamsterley Forest
 * Hopton Wood
 * Innerleithen Forest: Forestry England/Red Bull Project Downhill
 * Machynlleth: Cli-Mach-X
 * Thetford Forest

Difficult

 * The Forest of Ae: Ae Line (part of 7stanes project)
 * Afan: White's Level, Penhydd Trail, & The Wall
 * Argyll Forest Park: Glenbranter Cycle Splash & Ardgartan Peninsula Circuit
 * Ben Aigan: Blue Cycle Trail
 * Brechfa: Abergorlech Red Trail
 * Coed-y-Brenin: MBR Trail & Sport Trail
 * Cwmcarn: Twrch Trail
 * Dalby Forest: Red Cycle Trail
 * Durris Forest: Cairn Spur
 * Fetteresso Forest: Drumtochty Through Route Forest Trail & Bervie Loop Forest Trail
 * Forest of Dean: FODCA Trail
 * Gartly Moor Forest: Red Trail & Blue Trail
 * Glentress Forest: Red Grade Freeride Area & Red Grade Trail
 * Great Glen Forest: Great Glen Mountain Bike Trail
 * Grizedale Forest: Hawkshead Moor & Silurian Way Cycle Trail
 * Gwydyr Forest: Marin Trail
 * Hamsterley Forest: Neighbour Moor Tour Cycle Route & Red Cycle Trail
 * Hopton Wood
 * Kielder Forest: The Swinburne Collection
 * Kirkhill Forest: South Spur Cycle Trail
 * Llanwrtyd Wells: Esgair Dafydd Trail, Irfon Forest Route & Mynydd Trawsnant Route
 * Machynlleth: Mach 3 Trail
 * Bwlch Nant yr Arian: Summit Trail & Syfydrin Trail
 * Pitfichie Forest
 * Tay Forest
 * Whiteash Forest: Whiteash Loopie