So it's negative 40 outside and your beloved 130 flex boot is more like a block of cement or north of say 200 flex! What do you do? This is just a quick note on managing frozen ski boots, especially for ski racers.
Some would recommend that you remove one of the screws at the back of the boot (for race boots).
Just so you understand my math about that screw: a 130 boot at -40 is like a 200 flex or more - removing a screw reduces the flex by 10, so you get a 190 flex. You can see why I’m laughing at that idea.
There are other things more important about managing a frozen boot.
One is not tightening the top buckles very tight and rely more on the strap. That will make the boot significantly easier to manage when frozen, especially in GS.
The point is that the flex is given mostly by the front of the cuff and the back of the cuff. Loosening the cuff will allow you to use just the back of it, until forward enough to rely on the front of the cuff. That may allow just enough extra range of movement to be able to then effectively use the boot.