The tag `[mtb_scale][1]` [`mtb_scale`][1] might be of some value for this purpose. This is based on the [Single Trail Scale][2] system. Scales like this ,and the [SAC Scale][3] for walking, have been developed to maximise use of objective criteria, but use within OSM is often still subjective and inconsistent. [1]: http://wiki.openstreetmap.org/wiki/Key:mtb:scale [2]: http://www.singletrail-skala.de/ [3]: http://wiki.openstreetmap.org/wiki/Key:sac_scale

The tag `[mtb_scale][1]` might be of some value for this purpose. This is based on the [Single Trail Scale][2] system. Scales like this ,and the [SAC Scale][3] for walking, have been developed to maximise use of objective criteria, but use within OSM is often still subjective and inconsistent. [1]: http://wiki.openstreetmap.org/wiki/Key:mtb:scale [2]: http://www.singletrail-skala.de/ [3]: http://wiki.openstreetmap.org/wiki/Key:sac_scale