The event is Arrowhead 135, and it can be -30 or much colder up in northern MN (grew up there)-- changing a freehub isn't that hard and can be done if you're in the middle of nowhere and have no other choice but to walk or DNF... have seen multiple instances of failed freehubs in these events so I'm wondering whether it's a gear prep or environment problem... my experience in other ultras says it tends to be prep more often than anything else... anyone else have their thoughts on this??