Originally Posted by jo5iah
I dig the "S" system, with only one nit to pick: The grade percentages are pretty steep! A 40% grade is very steep, and 70% is pretty rare unless you're riding down cliffs. Trails just don't stay trails at that grade.
yes and no... SOME trails are that steep and that difficult - and yes, some aggressive mountain bikers do ride down cliffs -- i personally don't consider what i do riding down cliffs, e.g. Red Bull Rampage, but many people DO consider what i ride as "riding down cliffs" (S3 and S4). it's actually part of the REASON for a scale: so people can effectively exchange info about "difficult" trails.
but yes, most "trails" that people think of fall into S-0 and S-1 and for the average XC mountain biker S-2 would be described as "very diffucult".