I have to pull up on the latch rather than the backplate to keep the cable in. I get in by digging a slot in the front to keep from skidding - then stepping in.
That's what you should do... and make sure you don't have a bunch of snow under your boot...that will force the cable out of the guides when you tighten it. Another way is to use whatever is around. A tree, a trash can, a bench.... to help you hold your balance and lock in.
2017 / 18 -12- Kirkwood days
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