The omnipresent inconsistency in mountain bike trail difficulty ratings from region to region and country to country seems like an intractable issue. After my recent article on the topic, many readers commented and said that I was, in essence, making a mountain out of a mole hill. Some readers claimed that mountain bike trail difficulty ratings are “always regional,” and that there’s no possible way to make ratings consistent from one region to the next. In fact, after weighing the input from all of the experts that I interviewed, I’m inclined to agree with them.
However, there’s one organization that respectfully disagrees with that conclusion: the International Trail Rating System (ITRS).
The ITRS was founded by Edoardo Melchiori and Mischa Crumbach. Melchiori hails from Italy and Crumbach from Switzerland. The pair both have years of experience as professional guides. In addition to founding the ITRS, Melchiori is the president of IMBA Italia, and Crumbach works in engineering. This is important, because while the IMBA North America trail rating system is widely used in the USA and Canada, it’s rarely used in Europe.
According to the ITRS website, Melchiori and Crumbach developed their new system because “in 2020, there were at least 14 different trail rating systems in Europe alone to describe the ‘difficulty’ of mountain bike trails and routes, whereby ‘difficulty’ did not always evaluate the same aspects.” When I spoke with them, they mentioned that the number is now at least 20 systems.
Creating a unified system that can be applied to all mountain bike trails around the world is an ambitious task, but Crumbach and Melchiori took a very engineering-based approach and broke the problem down into its individual components.
Existing systems used to create the ITRS
The duo began by examining the most used trail rating systems around the world. The existing systems that they leaned on the most to help create the ITRS were the Single Trail Scale (STS), which is common in German-speaking countries; the IMBA North America system and its UK derivative; and the local Swiss bike park system.
After examining existing systems, they realized that different systems would rate a “difficult” route as difficult for different reasons. “Other systems would, for example, put the length of the trail — that at that point was a route, not anymore a trail — into the whole discussion about how technical it is, and put it all together and just spit out just one value,” said Melchiori. “So to make an example, it was like, ‘oh, this trail, this route is very, very hard.’ But you had no way to tell if it was very hard in the sense that it was very technical, or very hard in the sense that it was a gravel road, but 60 kilometers long with a lot of climbing.”
A four-part difficulty rating
After this critical realization, they determined that each and every trail needed not just one difficulty rating but four different ratings based on four different factors. The factors they settled on are technical difficulty, endurance, exposure, and wilderness.
Technical difficulty applies solely to the technical features found in the trail tread, and is “defined according to the riding skill level that you need for mastering the technical features of a trail,” according to ITRS.bike. This is the difficulty rating that most riders associate with trails, and is the topic covered in depth in my previous article.
Endurance is a fairly straightforward evaluation of how aerobically challenging the route is. To calculate the rating, the ITRS considers the total length, uphill climbing (vertical gain), and descending. It does not consider the use of a motor or different styles of bikes.
The exposure rating relates to the consequences you face if you fall from the trail. While some people question whether exposure should be factored into a difficulty rating, Melchiori shared a story about a person he once guided on a hiking trip. “Within the first 10 minutes, he was down on his knees crying literally. And it was not that exposed. But when you have people like that, and you don’t have any information about where is it exposed […] for some people, maybe it’s too much.”
Finally, wilderness is the commitment level required by the trail or route. The ITRS describes it as the “amount of planning required to account for rescue options, mobile phone reception, water supply, and dangerous wildlife.”
Each of these factors is rated individually for each trail and route. So, a trail could have an easy technical difficulty, require professional-level endurance, not be exposed at all, but be located deep in the wilderness away from assistance (for example).
Concretely, the ITRS utilizes the red color rating, similar to most trail rating systems in Europe. If you’re used to the IMBA North America system (which follows the North American ski resort rating scale), red replaces the single black diamond, while black is a double black diamond. So the scale goes: green, blue, red, and black. The ITRS has also added a fifth rating for technical difficulty and endurance: orange, which is essentially professional-grade technical difficulty and endurance. This orange rating has not been applied to exposure or wilderness (yet).
Does one black feature warrant a black trail rating?
One of the most difficult aspects of rating a mountain bike trail is determining how many technical features on a given segment of trail warrant increasing the difficulty of that trail. For instance, if a trail is mostly smooth and flat, but there’s one vertical rock cliff face along the way (that can be walked), do you rate the trail as green or as black?
To deal with this problem, in their app, the ITRS creates different trail segments that accurately reflect the technical difficulty along that segment. “If it’s really that extreme, and you have only one feature, we make a segment for that,” said Crumbach. “I would go into this trail, and like, for the first kilometer, everything is blue for me.” Then if you were to hit a really difficult spot while rating the trail in the app (more on that in a minute), “if it’s really only a 10 meter, super gnarly part, you may get maybe a 20-30 meter segment, which gets then black. Close it and the rest is blue again,” said Crumbach.
Crumbach was adamant that having one difficult feature does not make an otherwise easy trail a black trail, even though many people advocate for that approach. “No way, you cannot do that. Because then everybody would say, ‘oh, fuck, this whole route is black,’ and nobody would go there. But in reality, bikers would have fun on that route. This is from our guiding perspective, because we are both also bike guides, when you know, ‘okay, there are sections, which I cannot ride, but they are not pissing me off too much, because the whole experience that I have is still good.'”
Trails versus routes versus segments
The ITRS skirts that issue by breaking trails down into individual segments and assigning difficulty ratings to those segments. But as you may have intuited from the endurance and wilderness ratings above, some of these ratings don’t apply so much to short trail segments as they do to entire routes that you’d ride start-to-finish.
That’s intentional, because the ITRS rating scale is designed to be used for both trails and routes. Unfortunately, it feels like we’re right back where we started — is the entire route blue or black? But if you use the ITRS app for navigation, Crumbach claims they’ve solved the problem.
“If trails and routes are rated with the ITRS app, you will get all this information. You will get, in the end, ‘this route has like, 5% is red, and 10% is blue, and 30% is black,'” said Crumbach.
So how are the ratings assigned in the first place?
In order to assign these difficulty ratings in the first place, the ITRS has created an app which trained trail raters can use to scientifically measure a trail to assign the difficulty ratings. The app contains forms that need to be filled in with extensive details. For example, raters can measure things like the height of ledge drops, the width of the trail, the grade of the trail, etc. etc. The list goes on.
The process is complicated, so Crumbach and Melchiori are actively training people to act as certified ITRS trail raters. Eventually, they envision certified trail raters contracting themselves out to different mountain biking destinations, in order to bring the destination’s ratings up to the ITRS standards. Essentially, rating and reviewing trails could become a career, or at least a part-time job.
“The people that we train, they will of course not do the trail ratings for free. That’s the business, and we have a few people that have already started doing it,” said Crumbach.
Is the ITRS too complicated?
If you think this is all starting to sound complicated, you’re not alone. The most common complaint leveled against the ITRS is that it is too complicated. However, Lake Garda in Italy — one of the first destinations to implement the ITRS — conducted a survey to see how trail users liked or disliked the new system versus the old system.
The survey revealed that the ITRS signage was very intuitive to use.
“One of the questions on the survey that they did was, ‘did you already know the system?’ And the percentage of people that replied ‘yes’ was suspiciously high,” said Melchiori. “The way that we have interpreted this is that people didn’t actually know the system, because it was way too many people. It’s not realistic to assume that they already knew about it,” because this was one of the first implementations of the ITRS in the wild. The only other on-the-ground implementation had taken place roughly a month before in Switzerland, so it was highly unlikely that anyone had ever seen an ITRS sign in the wild before.
“But it’s actually a win for us, because it means that it looks familiar, and then they can understand it. So that was very positive, because the colors are the same that ski slopes in the US and Europe, and then most bike parks, use.”
This was the entire reason that the ITRS symbols and colors were based off of existing systems — because they wanted it to be easy for people to understand even without knowing the definitions behind every single rating or symbol. “The end result to the user doesn’t look like, ‘oh my god, what is this thing?’ It looks familiar. They say, ‘yeah, of course I know it,’ even if it’s probably the first time that they see it,” said Melchiori.
The most difficult hurdle will be adoption and implementation.
Even if we can agree that the ITRS has created an ingenious system to scientifically rate mountain bike trails that can then be used by every country around the world, the implementation of the system will still be the major sticking point. Crumbach and Melchiori know that there’s no way they can rate all of the trails in the world, which is why they’ve already started training other trail raters. But even with an army of riders armed with an app to rate trails, the process is arduous and slow.
As they seek to increase the adoption of the ITRS system, Crumbach and Melchiori are focusing on primarily spreading the system in Europe due to the existing challenges of traveling to ride in Europe, which has so many different trail rating systems. While the IMBA North America system is limited compared to the ITRS, Crumbach and Melchiori aren’t actively working to increase adoption of the ITRS in the North American market due to the widespread use of the existing system.
In Europe, the ITRS is slowly gaining traction. Destinations across Italy, Switzerland, Denmark, and Portugal are beginning to implement the new system, and the co-founders routinely receive requests from mountain bike destinations trying to figure out how to implement the ITRS in their region.
It’s clear that, especially in Europe, the ITRS meets a need for traveling mountain bikers. It’s no surprise that some of the areas that have implemented the system already are prominent tourism destinations, like Lake Garda, IT; the Canton of Valais, CH; and Lombardy, IT.
Furthermore, the ITRS is a fantastic solution for mountain bike destinations that are signing and rating their trails for the first time ever. As we saw in my previous article, signage even in some major mountain bike destinations is minimal or nonexistent.
Whether the ITRS will spread far and wide remains to be seen. But if you happen to be in charge of trail ratings for a local club, tourism organization, or mountain bike destination, you could be the one to bring the ITRS to your area. For more information on how to implement the system, be sure to visit their website.
