I am almost 68 years old. I have had a cross bike for years. But its wider tires always felt slower on the road. Recently switched to 700x32 GP5000s. Huge difference in speed and comfort at lower air pressure. I have lighter weight friends that went from 23s to 28s with similar results. If your existing frame, wheelset are suitable try going wider. Some good articles out there about tire size, air pressure and perceived vs actual speed.
I recently bought a Look 765 RS for gravel riding. Came stock with relatively heavy wheels and 700x37 tires. Added a set of road wheels and GP5000 700x32 tires. I no longer ride my Look 585 because it can't clear anything larger than 700x25. And because I am more comfortable I ride more often and longer. Resulting in faster average speeds.
Last edited by pennstater; 07-08-20 at 06:20 PM.