This may futher damage my credibility here, but I actually jam a Mobster 2.7 through a '03 SuperT arch. Any rocks that get caught in the treads are instantly removed by the arch, which means I ended up putting a front fender on to block rocks flying in random directions from the front of the bike. Stay out of the mud with this kind of clearance, I might add.
It gets worse. I squeeze a Gazzalodi Jr through there in the winter, and I have even less room in the back... I had to re-true the rear rim AFTER I mount the inflated mobster 2.7 and rim on the bike.