I was hiking a few days ago, and came across a highway=path with mbt:scale=5.
The path itself had like 5–10 obstacles which would let you have to dismount.
Like even if we talk about seriously insane skills, for the love of god, 2-3 of these cant be ridden.
And left and right of you is a hill (60-80% elevation directly next to you) and a river.
I’m pretty sure this is already a finicky topic, but, how does one want to address this?
You can ride this path with your bike in the same sense as you are able to ride a bike in some random forest without any mapped paths. But, there isn’t any sign stopping you.
I would tag this as a footway. But since I’m unsure about this topic, and the path was manually reverted from bike=no to mbt:scale=5, I’m unsure.
I would say that physical difficulty/physical-impossibility should never result in bicycle=no – that tag should be reserved for legal restrictions.
Depending on users’ goals, even paths with “completely unrideable” sections may be useful to some cyclists. For example, someone doing a long tour through an area may be willing to dismount and push/carry their bike over or around unrideable obstacles in order to connect other rideable paths. I’ve done this many times myself where I was able to explore many miles of trails interrupted by a few carries.
Alternatively, could you map each of the obstacles individually as a barrier=? On barriers, it’s fairly common to see bicycle=no meaning “physically impossible for a bike” though even that is controversial.
Please do not mess with mtb:scale=* unless you have a decent understanding of mountainbiking (and trials tricks at the upper end of the scale). mtb:scale=5 already tells even experienced mountainbikers that this route is probably too difficult for them.
I have hiked along paths in Italy that we found impossible to pass by foot (without any gear), but local mountainbikers had no problem whatsoever, they just jumped off the rocks I could not climb. I couldn’t have passed those in the other direction either. They also told us that the small rock-paths were much easier by bike then on foot.
(We tried to warn them about these impossible passages, they just laughed!)