Since the trend started here in 2002 thanks to Jacques Rilliet, many (most?) riders have modified their hard boots. At some point, there is the crucial question: how soft?
Of course, it depends partially on personal taste, but the height and weight of the rider should be considered first: we can't compare a rider of 190cm and 90kg with a girl of 165cm and 50kg. The same spring system (with same colors of springs and same setup) could be too soft for the guy and too stiff for the girl.
During the events, I have watched some riders who have probably too soft springs. For extremecarving, soft is good, but too soft is no good
I remember that in the nineties, I had some really soft Raichle boots (already modified thanks to Jacques), what was very helpful: good for progressing in moguls (where you have to "push-pull", as we named this) and for getting fluid style. So "too soft" is not necessarily bad. It works great on some terrains... as stiff hard boots work great on flat blue slopes too. To the beginners, I would recommend soft springs to learn riding "with the legs" and not only carving by balancing the body. Then, when the rider knows how to "push-pull", he can increase the stiffness.
Recently I tested some UPZ RC-8 boots with too soft springs and too soft plastic. From "outside", people could see no difference in my style. But from "inside", I could feel the lack of support on the tibias (in the frontside turns). Then I felt a bit less efficient and less strong in my turns. I also experienced some resonances (oscillations of boots) in function of the terrain: this is no good.
Beside the springs, the stiffness of the tongues and the plastic shell have to be considered. The way the entire boot is flexing is important. Ideally, the own plastic of the shell should not bend itself (like freestyle boots) because it doesn't allow a rigorous ankle rotation control.
So, what should be the criterias for choosing the proper springs and setup?
- 1) The boots flexion should be controlled by the spring system and the tongue only, not the plastic of the shell. It's important to get a good progression when bending the boots, like the linear resistance of a spring.
2) If you are big and heavy, use stronger springs.
3) If you are rather a beginner, use soft springs at start.
4) For riding fast on flat surfaces, you can choose harder springs. For extremecarving with a style inspired from surfing (as explained in this Website), don't choose too stiff springs.
5) If you extremecarve black slopes, and like mugles too, softness is better for fluidity.
6) Make tests! Your feeling is the main criteria.