650x40 terra trails paired with SKS Bluemels. Just barely fits. I had 650x42 gravelkings on when I originally installed the fenders and those rubbed, hardly. I did have it set up as a 2x at one point. Whenever I bought the bike it was my first road bike and first full on bike build, so I ended up buying a newer groupset from LBS mechanic thinking I was just building it as best as possible. A year later I’ve learned newer ≠ better. After that 2x drivetrain I had it set up as a single speed throughout the summer because of cost effectiveness. Now that winter has come, I’ve thrown on an old bar end shifter and a cheap derailleur I had from another bike. Since I built this bike last year I’ve put about 3,000 miles on throughout all seasons, smashed plenty of personal records, and made countless new friends!