Nice write up. That’s pretty much the criteria I use in Colorado.

To be clear, I agree smoothness is subjective, but so is tracktype. Even surface is subjective at times.

I don’t understand why folks think smoothness is subjective but tracktype is not?

HI John, I think you’re on the right track. I’m from Colorado, US, so my geography & road/trail conditions are quite a bit different from yours. So take my opinions with a grain of salt. I’ve been a mtber for a long time, also done some road touring here, Europe, & south east asia.

I disagree with Richard about smoothness, I think you should use it. I think smoothness is a really important tag for roads and bike paths, not so sure about mtb trails. Over here tracktype is pretty worthless. It is mainly about firmness. Most of the trails or roads here are rocky and very firm, but could vary from easy to extreme. Smoothness captures that better. Over there tracktype is probably more relevant.

Most of us over here use trailforks.com, mtbproject.com, or a local map to get an idea of what to expect. I’ve given up on OSM for this. The trail ratings used by those apps, and local maps are a green/blue/black rating similar to what is used on ski areas. Sure it’s subjective, but there is no other way to do it. It works pretty well. I think the green/blue/black rating system is used over there quite a bit too.

mtb:scale is so poorly written that I’ve quit using it. Max gradient for mtb:scale=1 is 40%?? 40% is virtually unrideable downhill or uphill. Others here use mtb:scale & mtb:scale:imba interchangeably. mtb:scale:imba is better, but unfortunately the :imba tag was incorrectly defined to be for bike parks (by OSM, not by IMBA). Someone tried to change it a while back & a couple of us supported that, but were met with illogical resistance.