While the latest hot trend in road bikes is the Gravel Road bike, that category wouldn’t even exist if not for the previous movement toward more comfortable yet high-performing road bikes called Endurance Road. The Specialized Roubaix, first launched in 2008, is widely credited for starting the Endurance Road category, which is defined by slacker head tube angles than their Road Race cousins, along with longer head tubes and chainstays/wheelbases. These characteristics are generally found on all Endurance Road bikes—there are other characteristics too, such as narrower, and/or shaped seatstays, skinnier seatposts, etc., but they can vary according to brand.
The results are a more upright position, which adds comfort especially to the neck and shoulders, and a smoother, more “compliant” ride, since the slacker angles and longer tubes allow more flex in the frame. Of course this comes with a compromise in terms of responsiveness and efficiency—that flex in the frames means less of the power input translates directly into motion. For all but the most serious riders and racers, however, this is more than made up for by the bike’s comfort and smooth ride.