Originally Posted by
livedarklions
Thanks! I would think that means they're using a constant for ground resistance, which is obviously absurd once you go off-road.
They do account for/make assumptions about rolling resistance with regard to bike type - indicating an MTB will get you a higher power estimate than indicating a cross bike, which will be higher than a road bike, etc. They also do have surface type info available on their route creator, though it's not comprehensive, so they could, in theory, add that as a factor in the future. That might be a lot of work to do for what'll still be a crappy estimate, though.