Silvretta 404 Classic Backcountry Skiing Alpine Touring Binding

Produced in a variety of colors including this scary pink, Silvretta 404 dominated the alpine touring binding market from around 1993 to 1998 and is still in use worldwide. It is readily available on the used market and makes an excellent approach binding for use with mountaineering boots (to prevent injury with such use we recommend not latching your heels down as softer climbing boots will not reliably actuate the safety release.)
Silvretta 404 ski touring binding was available in several lengths, adjustment for size range within those lengths was done by rotating a lever on the front of the unit where the boot heel rests. This disengaged two small catches that fit in the notches you can see in the photos above and below. On-the-fly length adjustment like this was a rare feature at the time, and a sought after feature for expedition use that involved sharing gear.

Silvretta 404 safety release is the good and the ugly. Vertical is good, accomplished by an alpine like mechanism built into the heel clamp (which sadly is not step-in, though it’s easy to click out of.) Lateral release is ugly, accomplished by the heel unit sliding sideways on a track and wheel system (visible in photo above) with little elasticity and a tendency to bind. More, this was an “explodomat” binding that required reassembly if you had a side release. Such was relatively easy on a work bench, but difficult while backcountry skiing with higher DIN settings and inclement weather.
Interestingly, all modern models of Silvretta bindings use some sort of lateral release mechanism that’s built into the heel unit, though the Pure series does not require reassembly after release. View video of lateral release action.

Touring lift is elegant for backcountry skiing — it’s a simple wire bail you flip up as shown in photo above. The bail is prone to detachment and loss during heavy use, but is easily replaced, and the binding works fine without it.
As for the 404 toe, the ski touring boot is held by a simple wire to bail as in photos above and below (fits some mountaineering boots as well, use for “approach” skis for climbs). This bail moves up and down to adjust for different sole thicknesses, but all lateral (side) release is in the heel, as noted elsewhere herein. The small slotted screw visible in the black plastic of the toe area adjusts tension of the return spring, which is the pink spring to the front of the screw. Return springs are intended to give some resistance to the up and down hinging of the binding, so the user has some control of the ski. Such springs have since been found to be unnecessary but are still favored by some backcountry skiers, and bindings such as the Fritschi models still have them, thought they’re easy to remove and are thus frequently taken out.

If you can find a pair, 404 still works well for stiff crampon-compatible mountaineering boots, and is popular as a climber’s approach binding. Please note that safety release is compromised in such use.

Detail of toe bail that makes possible the use of crampon compatible mountaineering boots instead of ski boots.

Switching from tour to ski mode is done with this simple latch, shown in ski mode. This is operable with a ski pole, and allows an excellent foot-flat-on-ski mode for long low-angled treks while backcountry skiing. View video of touring latch in action.
Make comments about Silvretta 404 ski touring binding.
Silvretta 404 Mounting Instructions
Weight: 36.3oz, 1027 g (one binding, with screws)
These bindings were donated to the WildSnow collection by Jim Gilchrist, thanks

Silvretta 404 thumbnail.