Mountain bikes, gravel bikes, are slow Given the huge difference between the 2 I'm not sure what you mean? Also because these days 'mountain bike' is an umbrel

Mountain bikes, gravel bikes, are slow Given the huge difference between the 2 I'm not sure what you mean? Also because these days 'mountain bike' is an umbrella term, whereas gravel bike is still rather specific. E.g. that last link shows already a rather specific segment of maountain bikes: dual suspension, quite a lot of travel on the front suspension, totally suited for going down the hill fast as well.