Today, I am answering a question that seems to be asked daily, which tire and tire size are you running on your gravel bike? MTB tires on gravel bike is the hottest trend right now. From the Schwalbe Thunder Burt, The Continental Race king 2.2, The Vittoria Mezcal and more… They are the buzz cause they offer more comfort, better puncture protection and they often offer less rolling resistance than most actual gravel bike tires. So, will the Race king 2.2 fit on the Trek Checkpoint Gen3. Let’s find out.