route=mtb is for routes that can only be used by mountain bikes and are of a “challenging” nature.
route=bicycle is for all other bicycle routes, including those for touring and commuting. You should use surface= tags on each individual way to describe what the surfaces are. That way, route-planning websites can best choose which paths and roads to follow.
A router will often give an improved weighting to ways that are part of a bike route. It would not be a great idea to do that for ways that are part of an MTB route if you’re not actually riding an MTB.
Pedja, did you ever encountered MTB’s as being a cyclist if so you would know. A cyclist rides and a MTB works to get around:) Besides the types of cycles are different a MTB is shorter then a fi Randonneur.
I had the same question - I mapped some time ago a few relations for local “Mountainbike” routes e.g. 15 km were on asphalt, and only 1 km on gravel (flat, easy to ride). On the web site of the local community it is called “Mountainbike Tour”, in fact it’s good enough for any bike, except racing bikes I would say.
Originally, I marked it with route=mtb, but now I see that certain cycle websites and routers are not considering it as bicycle route at all. They should prioritize it if somebody is searching for the best bike route from A to B.
I think I will reclassify to route=bicycle, as it can be visible to all cyclists out there. In the detail segments they anyway can see that there is a gravel part.
I assume “mtb” makes sense only for routes that have passages which are really only suitable for mountainbikes (single trails, paths throught forests etc.).