On the climb from 550 to the pass itself, there's one switchback where I'd turn around if I didn't have good ground clearance or traction.
This is a GM streetview of that spot:
https://goo.gl/maps/rCkr8c9ocVxAnother view of that step from above:
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After that set of switchbacks the road over Black Bear Pass to Ingram Basin looks open and relatively straight.
http://www.off-road.com/trails-events/trails/exploring-the-infamous-black-bear-trail-54560.htmlFrom this description it sounds like backtracking from the pass would be going against traffic, which may be too heavy to do it politely.