I thought 25mm tires were fine on gravel until I rode 40 miles on chunky stuff in Boulder
Ran 25s on my old steel frame for two years because that's what it came with. Last weekend a buddy dragged me out to some chunky gravel roads west of Boulder, and by mile 12 my wrists were done. Switched to 38s the next day and rode the same loop. It was like a totally different road. Anyone else make a tire width jump this big, and did you notice a speed loss on pavement?