Muni Difficulty Scale

Comments about this discussion:

Started 18 Feb 16:38

The Muni Difficulty Scale is incorporated with current Rulebook

My experience from using the Scale for planning the course for Unicon 20 in Grenoble was not satisfactory.

Imagine the XC trail that climbs up on asphalt or gravel road and descent on M3 steep single trail. Using the current scale a total score would be the same with no respect in which direction is the course run. For many it would not be a problem to ride the course with uphill on the road and downhill on steep single-track but if when reversed, it actually becomes unrideable. However, in both situations the score result is same. That is extreme situation only to show that the problem is that the Scale doesn't distinguish if the sections are uphill or downhill. For example M3 downhill is OK but M3 uphill would be unrideable. Another issue with lengths, 40km is maximum scored length, so either it is 42 or 72 km the score is the same. Similar with elevation gains.

My conclusion is that it is impossible to score the difficulty of the trail by scoring each single component of the characteristic of the trail. The equation would be more sophisticated then just algebraic sum of 4 criterias. The experimental version of the Scale failed the real test.

We should remove References to the Muni Difficulty Scale from the Rulebook and amend the articles with proper wording.

In my opinion the experience is more important than judging difficulty by the scale.

In respect to venues, the race directors should rely on their experience and opinions of experienced riders and taking consideration of the current level of the sport.

Comment 20 Feb 10:39

I agree. While it might be possible to develop a more workable set of metrics, it would need real-world testing before being implemented. It's a good thing we don't mind traveling 2-3 hours from a main venue (large conventions) to the Muni courses to figure this stuff out... :-)

The trails at Unicon 21 were also a good example of the need for flexibility in the courses in relation to weather, where some routes had to be changed due to one or more big storms that created some problem erosion. We had similar problems with NAUCC in South Dakota in 2008, where the summer weather seems to come with a chance of thunderstorms every night. While the Muni venue was right in the city, the courses had to be modified on multiple days due to weather from the previous night.

Comment 23 Feb 05:04

Initially, the idea was to help organizers not familiar with muni as a discipline to provide suitable tracks for competition. Not only for Unicon or dedicated muni events, but also for national or continental events. While this has not really been an issue for dedicated muni events, it has also improved for Unicon I would say, where organizers have the means to shuttle participants to a suitable location far away. I'm more concerned about smaller multi-discipline events, e.g. NAUCC, CFM, etc. where the muni events are often not up to the highest standard (of course, also due to the limited resources of the organizers, which is understandable).

I agree that the metrics from the Muni Difficulty Scale might not be needed in the rulebook anymore as in general the awereness has increased of what are suitable muni courses for competition. As long as the resources on the muni difficulty scale are still hosted by IUF somewhere, the organizers can compare their proposed tracks with those from previous events out of their own interest/curiosity. When making this change, we would need to find some appropriate alternative wordings in the rulebook to replace the current implementation in the rulebook. I like the idea to rely on experienced riders for advice.

Comment 23 Feb 07:52

While this is a complex topic, I tend see it more as Ben has suggested, as a general guideline for those who have little knowledge and experience and not the primary too for selecting tracks. For something like Unicon, the tracks should for the most part be selected by experienced riders using their subjective judgement. However, even here, the Muni Difficulty Scale could be useful after the course has been established to communicate to riders what to expect in the races.

As to Maksym's comment about uphill/downhill, I think that the M rating is only applicable to downhill sections (I am much more familiar with the Mountainbike Singletrack Scale which explicitly states that it only applies to downhill sections and a separate scale is used to rate uphill sections).

In general, I think retaining the information and the reference to the IUF Difficulty Rating for Muni Trails in the rulebook as a general guideline is preferable to completely removing it: It can also be useful to Newbies who can maybe get a feeling for what to expect in general (Personally, the detailed descriptions for length and difficulty were helpful to me as preparation for my first muni event).

Perhaps we should consider modifying it so the Muni Difficulty Scale and the course ratings are very general guidelines for the course and track selection (but state the course selection relies more on experts than fulfilling the scale), and change the primary intention of the ratings to be to informative so riders can prepare in advance and potentially objectively compare courses. Or even change it so the course rating is only after the course has been chosen.

In this respect, it would probably be more useful to list the individual category ratings (rather than just a combined score), e.g.

DH: course length, total elevation loss, max M-scale difficulty, average M-scale difficulty

XC: course length, total elevation gain/loss, max M-scale difficulty, average M-scale difficulty, max uphill grade (and possible surface percentages, e.g. 10% paved, 30% dirt road, 60% singletrack)

At I minimum, I think the rulebook should have a reference to the Difficulty Rating for Muni Trails.

For something like the CFM, where muni is very much a side event, it would be very helpful to have M difficulty ratings, so riders know more what to expect. My estimates max M-difficulty of 1.4 and average M-difficulty of 1.1 for the 2023 CFM DH would be helpful as objective ratings: Most muni riders would consider the course very easy even though many of the French (non-muni) riders found the course to be very challenging, and I heard many French riders describe the course as "very difficult".

Has anyone attempted to make M-scale ratings of the tracks of the last few Unicons? I think that would be a useful exercise. (Section 4.4. of the IUF Difficulty Rating for Muni Trails suggests that events ratings should be published at https://muni-scale.info/ but either the URL is wrong or the site is down.)

My subjective ratings Bemidji/Grenoble:

uphill at Bemidji was significantly easier than Grenoble (shorter, less steep and significantly less elevation gain).
DH at Bemidji (average M1, max M3) was roughly equivalent to the Grenoble Qualifier (average M1, max M2.5) and significantly easier than the Grenoble Final (average M2, max M4), but the Bemidji course had much less elevation drop.
XC at Bemidji (average M0.5, max M1.5) was technically much significantly easier than Grenoble (average M1, max M3.3) but the Bemidji course was more strenuous/taxing (The Grenoble XC more technically difficulty than Grenoble DH Qualifier).

Comment 23 Feb 07:59

Actually, the current wording in 4D.1 reflects this pretty well and doesn't really need much of a change:

"Downhill and Cross Country courses must be rated in advance by two people using the
appropriate IUF Muni Diculty Scale (see the IUF publication and online calculator).
Ratings and their underlying data must be published at least seven days prior to the
event." --> only states it must be published well enough in advance.

And 4D.1.2 also only states a minimum:

"The overall course diculty must be rated with the
Unicycle Downhill Scale. A minimum score of 20 points is recommended. Courses with
scores below 15 points should be labeled beginner downhill for clarity."

Perhaps only a clear statement that the difficulty rating is an informative assessment rather than a limiting design guideline for course selection?

Comment 23 Feb 10:04

I agree to Nathan's observation that: "it would probably be more useful to list the individual category ratings (rather than just a combined score)"

MDS doesn't work for both XC and DH Courses. In both cases it assumes that steeper the slope, the more difficult section is. Which is not true in many cases, because in some grades, the gravity helps to roll over obstacles, and in other grades it adds to difficulty.

The only way to properly rate the trail is to ride it and get filling of it. Description of the trail with use of M-Scale for categorizing type of sections and supported with objective feeling from riding it should be sufficient to understand difficulty of the trail, and perhaps is the only solution we can offer at the moment

We could work on new document: "Guidance on rating Muni Trails", and reference this document in the Rulebook, but currently we have not anything suitable.

Regarding calculation part of the MDS for rating UXC and UDH:
This was an experimental thing and although it may appear that it works satisfactory, it is not always the case. Anyway, I don't know of anyone using this scale to grade the trails. The official page is down for a years now. Unicon21 did not present the scale ratings. Please educate me if I am wrong, but for the times being I don't see reason to keep the MDS. I personally thought it was a good and cool project, but the MDS metrics doesn't really work. I am for removing the MDS from Rulebook and I would strongly consider to remove it complately from IUF web or made adnotation: Historical/Experimental/Unsancioned

However, I agree that description of the trail is important, not only for the newbies but also to experienced riders who need to prepare adequately to the race.

We could probably work out set of criterias for description.