This course favors a cross bike with knobby tires, but you can bring whatever you want. I’d be very surprised if someone on a mtb wins this thing, but there are parts of the course where you’ll wish you were riding full-suspension.
Beyond that, bring what you need to survive 100+ miles of intense riding. I recommend you leave food at the drop station….and eat a giant bowl of wheaties on race-morning.
And don’t forget to carry some cash, there will be ONE place along the course where you can buy some food.