Singletrack difficulty scale

The singletrack bike tour scale created by the MTB Guides of Feltre Bike Tour includes six degrees of difficulty, from the lowest S0 to the highest S5. The scale singletrack bike tour is evaluated exclusively the technical difficulties of a path or mule track, flat, downhill, or uphill. The value assigned to a trail is chosen by averaging the degrees of difficulty that a trail has for the most part. This does not preclude a trail-rated S3, for example, from including sections rated S2 or S4. The rating also considers the trail in dry weather conditions. The parameters used to determine the degree of difficulty are  - the type of terrain (grip, smoothness, geological composition) - the type of obstacles slope type of curves necessary for driving skills.  As you can see the exposure of a path and the dangers are not taken into account. Sometimes you can find a + sign after the trail classification (e.g. S2+). The + sign simply indicates that the route is slightly more difficult than a normal S2 trail, but does not fall under an S3 classification.

First level S0

Indicates a single trail that does not present any particular difficulty. These are mostly smooth trails in the undergrowth or on open plains that have a good grip or slightly loose cobbles. In this type of path, you will not encounter steps on steps, rocks, or roots. The slope of the trail varies from slight to moderate and the curves are always quite wide. The S0 trails can be hiked without any special technical skills.

In brief
Trail conditions: compact terrain with good grip
Obstacles: none
Slope: slight to moderate
Curves: wide
Driving technique: no special skills

Second level S1

Small obstacles such as shallowly protruding roots and small stones will be found on an S1 trail. Often the reasons for an increase in the degree of difficulty of a trail relate to the presence of drainage ditches or erosion damage. On S1 single trails, the terrain can sometimes be loose. The gradient reaches a maximum of 40% and no hairpin bends will be encountered. However, starting with the S1 level of difficulty, you must be familiar with basic riding techniques and maintain a good level of concentration at all times. The most difficult passages require a measured use of the brakes and the ability to influence the trajectory through body movement. The obstacles can all be overcome with basic riding skills.

In brief
Course conditions: possible loose ground with small roots and stones
Obstacles: small obstacles (gutters, erosion damage)
Slope: <40%.
Curves: tight
Driving technique: basic driving technique skills

Third level S2

The S2 classification includes routes with larger roots, stones, steps, and stairs that are not very demanding. You will often encounter tight, almost sharp bends and gradients of up to 70% in some sections. Obstacles can only be overcome with a fair amount of driving skills. The ability to break at any time, together with the ability to shift the balance points of your body, are necessary techniques for the S2 level. It is also necessary to be able to apply the brakes precisely and to keep the body active at all times while driving.

In brief
Course conditions: often loose ground, overhanging roots, and stones
Obstacles: various obstacles and steps
Slope: <70%.
Curves: narrow, almost sharp curves
Driving technique: advanced

Fourth level S3

To the S3 category belong single trails that have many technical passages made of rock blocks and/or roots. You will often encounter high steps, hairpin bends and difficult slopes, and rarely smooth passages. Often you have to deal with slippery and loose ground. Sections with a gradient of over 70% are not uncommon. The S3 passages do not require the use of trialist technique, however, excellent bike control and continuous concentration are necessary. The ability to brake with good precision (i.e. mastery of brake modulation) and excellent balance is essential.

In brief
Course conditions: technical, frequent protruding roots and large rocks, slippery and not very compact terrain
Obstacles: Steps
Slope: > 70%.
Curves: narrow and sharp bends
Driving technique: more than advanced

Fifth level S4

The S4 category includes very technical single trails with large blocks of rock and/or particularly challenging root passages on terrain that is often not very compact. You will often encounter ramps with an almost extreme gradient, narrow hairpin bends, and steps, the latter high enough to considerably increase the risk of contact with the crankset crowns. For these paths is therefore strongly recommended the use of a
bash guard. To be able to ride S4 trails, trialist techniques are necessary, such as the ability to move the front or rear wheel (for example in sharp turns), a perfect braking technique, and an excellent balance. Only those who love extreme and very technical riding can complete an S4 trail. The most technical sections of S4 courses are often difficult to negotiate even on foot.

In brief
Course conditions: technical, frequent protruding roots and large rocks, slippery and loose ground
Obstacles: steep ramps, very high steps (often at crown height or more)
Slope: >70%.
Curves: very narrow hairpin bends
Riding technique: perfect control of the bike and trial technical skills such as shifting the rear wheel in sharp turns.

Sixth level S5

The grade S5 is characterized by a very technical terrain that often presents counter-slopes and slippery bottom, tight turns, steps of different sizes that follow each other, and obstacles such as fallen trees.
and obstacles such as fallen trees. All on slopes that are often extreme. The braking distance is usually very short and sometimes completely absent. Often the obstacles are in close sequence. Only the experienced and safe driver dares S5 passages. On this kind of track sometimes obstacles can only be skipped. In sharp bends, there is often very little space. In some passages even walking with the bike on the shoulder is extremely difficult, in some cases, due to the slope, it is necessary to hold on to firm points and, sometimes, even to hold on to the bike.
and sometimes even climb.

In brief
Route conditions: very technical with counter-slopes, slippery and loose ground, the S5 route can include short sections similar to the high mountain dirt or gravel road.
Obstacles: steep ramps, steps that are difficult to climb and in close sequence
Slope: >> 70%
Curves: very tight hairpin bends with obstacles
Driving technique: excellent command of trial techniques; the movement of the front and rear wheel is only possible in some cases