SKI BOOT FLEX
Ski boot flex is not standardized. It is not a myth either. If anything, ‘flex’ is a relative indicator of ‘directness’. There are several aspects of a ski boot that influence this ‘directness’, and therefore ‘flex’.
A few things factor into the directness of a ski boot. Stiffness or the materials is one of the factors. Not just of the hard outer shell of the boot, but also the materials used in the liner have great effect. The stiffness and thickness of the liner and the overall snugness of the fit – they all contribute to a greater directness of the boot.
By ‘snugness’ I mean not just the last width of the boot. Around the ankles, the heel, the lower leg – the tighter the fit, the more directly input by the leg is transferred to the binding and the ski. The strap even is a factor. A different strap or liner can mean the difference in flex between two boots, even if the hard outer shell is the same. An example of this is the Head Raptor 140 RS and the Head Raptor 120 RS. Only the liner and strap are different, but the difference in flex is ‘20’.
Snugger fit, higher flex
Lange and Rossignol are two brands under the same parent company. Their race boots (the ‘world cup’ boots for both racers and for recreational skiers) have identical measurements, materials, liners, construction methods etc. The only difference is the color, literally. The Lange men’s RS 130 boot comes in two widths: 97 mm and 100 mm. The wider one is called ‘wide’. In every other respect, the boots are identical.
Rossignol has the same boots, but puts them on the market as ‘Hero World Cup 140’ (the 97 mm version) and ‘Hero World Cup 130 Medium’ (the 100 mm version). So, one brand poses them as the same 130 flex boot, but in two different widths. The other brand poses the narrower one as a 140 flex and the wider one as a 130 flex boot.
This shows two things. First, flex is – as we already knew – not standardized. Second, the width (or rather, the lack thereof) contributes to a higher flex. At least, according to Rossignol.
Fit over flex
There is not one particular rule of thumb when it comes to determining what flex ski boot you need. It is simply a question of how direct you want them to be. And no, a higher flex boot does not mean automatically that it will be less comfortable. A well-fitted boot does not hurt or cause any numbness or cold feet. Nor does ‘well-fitted’ just mean the ‘correct size’. It means having an actual boot fitter fit you a pair of boots.
And that’s what is most important in choosing a pair of boots: they should fit. They should fit physically, as well as the type of skier that you are (the body you have and the type of skiing you want to do). So, don’t go into a shop ‘knowing’ you need a 120 flex boot. There simply is not such a thing as a 120 flex boot. I hope I have shown you at least that.