Yeah, a buddy of mine biked Mt. Evans last year after it closed to motor vehicles after Labor Day. A ranger told him it was still open to bikes, etc., but that you're on your own.
Biking Mt. Evans was both a fantastic and nerve-wracking experience. The camaraderie among cyclists is great, lots to see, and the incredulity of the tourists is funny. But the road and traffic really suck: "football"-size potholes you have to be vigilant for, lots of jarring cracks, no shoulders, no guardrails, and often steep dropoffs. The descent on the east sides of Mt. Warren and Rogers Peak had all that, plus often huge SUVs like Escalades trying to drive by one another on the narrow road.