Blue – Red – Black. Everyone who hits the slopes is familiar with this system. Even in the snow, this classification is a rough approximation of reality. Nevertheless, it has found its way into trail classification. The German single-trail scale, which ranges from S0 (no difficulty) to S5 (terrain for trial experts), is more precise. However, this does not apply to built trails.

Schweizmobil and the Swiss Council for Accident Prevention (BFU) have expanded the blue-red-black scale and published it in the “Implementation Guide for Mountain Bike Trail Network Planning.” The categories of easy – moderate – difficult have been replaced by very easy (green) – easy – moderate – difficult – very difficult (purple). At first glance, this seems simple—as if they’d just added something at the top and bottom to cover what was previously represented by blue or black.

But of course, it’s not that simple. New criteria have been added at both ends of the scale, and the boundaries in between have shifted as well. Benedikt Heer also draws a comparison to skiing: “Green corresponds to the children’s area or the practice slope. It’s the place where toddlers can ride over obstacles on their 12-inch balance bikes, and where adults who want to practice in a safe environment—for example, on a newly purchased e-MTB—can do so in a forgiving and self-explanatory setting.” The criteria for green are so strict that there are hardly any existing blue MTB trails that meet them. “This infrastructure is only just now being developed,” the expert explains.

Black, previously the top end of the scale, was a vast catch-all category ranging from challenging to extreme. According to Heer, the new approach is that while black trails are challenging, they can still be ridden by a significant portion of mountain bikers. “The Black difficulty level marks the upper limit for recreational mountain biking. Purple trails are intended for very experienced mountain bikers who are aware of the increased technical demands as well as the associated risk of accidents and injuries.” 

Difficulty Expressed in Numbers

The guidelines provide clarity on where the limits lie. A black trail may have an average maximum gradient of 30 percent; the maximum gradient of ramps (steps) may be 90 percent, or 42 degrees. Uphill, an average maximum gradient of 16 percent is permitted, with a maximum of 20 percent for ramps. Anything above these values is classified as purple. There is no upper limit. 
These numbers aren’t all that useful on the trail or when planning a tour—after all, who can really estimate or imagine whether a trail has an average gradient of 30 or 35 percent, or whether a steep step is steeper than 42 degrees or not?

As with all existing scales, experience helps. The red or black trails that someone has ridden serve as a benchmark. From this, you can deduce what technical challenges await you on an unfamiliar trail. Benedikt Heer adds: “We’re working on a communication strategy for mountain bikers so they know in advance what to expect on the MTB trails.”

The document describes the “Violet” rider type as follows: “You possess exceptional technical skills: You can ride extremely demanding trails or courses. You maintain control during very difficult maneuvers on the ground or in the air.” The requirements for black trails are also high: “You possess very good technical skills: You can ride down or up extremely steep sections and, if necessary, lift the front or rear wheel. You can confidently drop or jump over obstacles and control your body position in the air.” Further details on the characteristics of the various difficulty levels can be found in the appendix to the Implementation Guide for Mountain Bike Trail Network Planning.

Existing trails are now classified as more difficult

The boundaries between blue and red, as well as between red and black, are no longer where they used to be. According to Benedikt Heer, these have been shifted slightly downward. In other words, some blue trails are now red, and some red trails are classified as black under the new criteria. The goal is to ensure that people who want to ride green or blue trails, in particular, don’t encounter any unpleasant surprises but instead find safe and forgiving MTB trails.

The new difficulty levels and their signage are mandatory for built trails in bike parks—not immediately, but as part of maintenance over the next few years, explains Dominik Hug, project manager at Schweizmobil. These parks also have a commercial interest in providing their guests with precise information about what to expect on the trails. The same applies to community trails in local recreation areas. For all “bike-only” trails, correctly indicating the difficulty level is mandatory, Heer explains.

Indicating a difficulty level remains voluntary for singletrack trails shared by hikers and cyclists. “In certain places, a sign indicating the difficulty level would send the wrong message,” says Hug, referring to popular hiking trails that could consequently be perceived as bike-only trails. Heer, however, expects that bike destinations will also begin to mark their shared-use trails in the medium term, because indicating difficulty levels also has a guiding effect.

Difficulty ratings mandatory on dedicated MTB trails

The interesting question is who will be responsible for classifying the difficulty levels. In total, there are likely several tens of thousands of kilometers of trails to be assessed. Hug comments: “This should be done by experts who have the necessary know-how, such as trail builders, shapers, or project managers. The destinations have the people who can do this.” It remains unclear who will classify the thousands of kilometers of singletrack trails that aren’t managed by any specific tourist destination. Many municipalities lack the necessary expertise for this. According to Benedikt Heer, the plan is for all singletrack trails recorded by Schweizmobil to be labeled with a difficulty rating on online maps in the medium term.

In summary: Built bike trails in bike parks and recreational areas must be labeled according to the new scale in the near future. Schweizmobil is deliberately not setting a deadline for this. Single trails in open terrain will eventually be assigned difficulty ratings online. However, don’t expect to see a flood of new signs there. It’s also clear that, during the transition period, some trails will still be labeled according to the old system, while others will already be labeled according to the new one. Ultimately, assessing whether a trail or tour matches your skill level remains a matter of experience. This is no different with the difficulty ratings in the Ride Tour database.