It’s not steep, it’s just a fast B road traffic speeds along, and can be dodgy going downhill in the Grassington direction, being dead straight with good lines of sight, so bikes go easy over 40 mph if the usual westerly isn’t blowing too hard. Trouble is that there’s a bend at the bottom of the fast bit for the actual bridge where I’ve heard of two cyclists being killed after going over the edge. There’s a mesh barrier there now as a result.
Just googled (goulish as it is most locals will know a couple of associated tales) and it looks like quite a few folks have come to grief there on bikes https://www.google.com/search?q=cyclist+dibble%27s+bridge&rlz=1C1GCEA_en&oq=cyclist+dibble%27s+bridge&aqs=chrome..69i57.7824j0j7&sourceid=chrome&ie=UTF-8
partly reflects just how many bikes there are on that road I guess