Originally Posted by SethAZ

Why stop there? On my old bike I had 23mm at first, loved the upgrade to 25mm, and could run 28s depending on the brand, but with GP4K I could only fit 25mm up front and 28mm rear. With my new bike I'm rocking 32mm and loving it so much I'm contemplating shelling out for their 35mm model, just to see if it keeps getting better or 32mm was the peak goodness. I had personally applicable Strava data on routes I rode a lot with the 25mm and 28mm tires and then with the 32mm tires, and not only didn't see any drop in performance, but if anything, saw a slight gain. Since my frame and fork support these sizes, I won't ever go back.