1. Front foot angle.
Lucky me, I can ride at the same old angles I always have on this board.
When setting the angle of the front binding, the goal is to achieve optimal mechanical advantage without incurring boot or binding contact with the snow when the board is at extremely high edge angles. The other important consideration is the angle at which your body functions best. Sometimes I feel like the 57/60 I rode on my old PJ 6.2 and Stat 5 felt better than the 60/63 that I have ridden since about 1994.
This is what it looks like from the top. The funny looking thing is the lower shell of a retired boot. (Sharp eyes will notice that I have the right shell in the left binding.)
Though it appears the boot sole is hanging over in a rather dangerous manner, the stack height of the base disc provides plenty of clearance. On a carpeted surface, tilt the board to 90 degrees and bend it until most of the edge hits the carpet. If you have clearance now, you will have clearance on the snow. You are not likely to reach this steep an angle during everyday use, but, if you fall on a steep, icy pitch, at least you can self-arrest without an ice axe.
One advantage to riding in stiffer boots is that you can ride at steeper angles. Steeper angles allow for a better utilization of the systems inherent to the body, which facilitate balancing in an upright posture. (Of course, if you go too steep, i.e toe and heel inboard of the edges, you lose leverage and potentially overstress the binding bails).
When we walk, we propel ourselves from heel to toe, and sometimes from toe to heel. This foot movement is referred to as plantar flexion (pushing down with the ball of the foot) or dorsi-flexion (lifting the toes towards the kneecap). On this axis there is a fair amount of power and considerably less dexterity. We remain upright as we walk by making subtle medial/lateral movements of the ankle joint. These are referred to as inversion and eversion. Inversion and eversion can take place simultaneously with dorsi/plantar flexion, most effectively within a certain range. Inversion and eversion, while not that powerful, are fairly well tuned and accurate movements. Given the fact that an alpine snowboard is a little like a racing motorcycle, fine tuned handling is an advantage. The rigidity of the plastic boot shell supports the balancing function of the foot at ‘high’ stance angles, as long as it is stiff enough, is a good contour match, and is used with an adequate binding. Giving the fact that we have been tuning our abilities to effectively invert and evert our feet ever since we first learned to walk, it seems logical to maximize the potential of this finely tuned trait when we ride.
That having been said, riding in a stiff boot that has not been properly fitted and/or customized, on bindings that have not been set up properly, is a recipe for pain and disaster. Though I don’t recommend that everyone use ski boots, the following photos show boots that have been tuned and work quite nicely. The primary advantage to using ski boots is the improved lateral rigidity, solid sole contact area, and the fact that they are actually foot-shaped. This is an important consideration if, for instance, you have narrow ankles and a broad fore-foot.
On stance angles in general. (Leverage v. finesse)
As mentioned earlier, steeper angles allow for greater dexterity, but less leverage. Similarly, lower angles allow for less dexterity, more of a ‘learned’ style of riding, and greater leverage over the board. One might think that more leverage is a good thing, but that is not necessarily so. If the mere act of relaxing your legs sends tipping input to the board, then the board is doing something when you are doing essentially nothing. Difficult toe side turn initiation is often directly related to either an excessively low stance angle, or too much splay angle between the feet. In this case, steeper angles or less splay would mean that knee flexion would travel more tip to tail, which would allow the rider to relax their stance without incurring dissonance underfoot. If you find then, that most toe-side turns are initiated with the upper body, or if the rear leg tends to straighten and/or lock under similar circumstances, you could have a binding angle/boot incompatibility. To check this, loosen the cuff of the rear boot and try to make a few slow, gradual turns on gentle terrain. If the situation improves, then you need to reduce the leverage provided by the rear boot.
Simply put: Stiffer boot, steeper angle. Softer boot, lower angle. Wider board, softer boot. Narrow board, stiffer boot. Got it?