Originally Posted by Redbullet

... As a non racer, I would say that my recent move from 23 to 28mm tires (same brand / type) and 1 kg heavier bike can be felt as having a negative impact on performance, although the new bike claims some further aero gains such as: optimized fork, aero “D” shape for seat post and tube, carbon aerodynamic handlebar, 1 cm longer reach and (roughly) 1 cm lower handlebars. However, the new bike feels less agile, a little harder to accelerate and marginally slower on steady rides on flat roads. I didn’t try climbing yet, but I doubt it would feel better.