Salomon S/Pro Supra S Boa 100 Ski Boots 2027

The Boot

The Salomon S/Pro Supra S BOA 100 is an all-mountain ski boot built around a 100mm last, a flex index of 100, and a closure system that combines two aluminum buckles with a BOA® dial on the lower shell. The shell and liner together form what Salomon calls ExoWrap™ construction — the dial cinches a network of guides and lace across the forefoot, pulling the liner against the foot rather than just clamping down from above. It's a fundamentally different feeling from a standard four-buckle setup.

Who it's For

This boot fits intermediate to strong-intermediate skiers who want a dialed fit without fighting a stiff shell all day. If you're skiing blues and groomed blacks comfortably and you're ready for a boot that actually holds your heel, this is the range. The 100mm last works for medium-width feet — not narrow, not wide. Bring your foot in and we'll tell you honestly where you land. A skier pushing into more aggressive terrain or already at an expert level will likely want to look at the 110 or 120 in the same line.

Flex & Fit

Flex 100 is a medium flex. It's not a beginner boot and it's not a race boot. On firm morning snow it gives you enough resistance to actually feel what the ski is doing; by afternoon it won't have you fighting it to get home. The 100mm last at 26.5 is the reference width — each full size steps about 2mm from there, so a larger or smaller foot will see a slightly different fit. Custom Shell HD heat-molding can push the last to around 100–106mm, which gives bootfitters real room to work with for wider forefoot shapes. The riveted cuff alignment pivot is adjustable, so we can tune the lean and alignment at our boot fitting bench rather than shim-and-guess.

If you want to understand how flex numbers translate to skiing, our blog post on ski boot flex ratings breaks down exactly what the numbers mean for different ability levels and skiing styles.

Tech that Matters

ExoWrap™ construction: The shell has strategically thinned walls at the forefoot. The BOA® dial pulls cable and guides across those thin spots, wrapping the foot from the outside in rather than buckling down from above. The result is a more even contact footprint with less pressure buildup across the instep.

BOA® Fit System: One dial on the lower shell. Turn it to tighten, pull it to release completely. Left boot tightens counterclockwise. It's micro-adjustable across the full range, so you can loosen slightly for the lift and tighten again at the top without taking your gloves off for long.

Custom Shell HD: Heat-moldable lower shell. We do this in-shop. It takes about ten minutes and produces a shell that's shaped to your foot rather than asking your foot to adapt to the shell.

S/Pro CF Liner: Thermoformable, pre-shaped at the ankle, elastic toe box. It won't pack out the way a basic foam liner does because the form is heat-set, not just compressed foam.

GripWalk Sole: Rockered rubber toe and heel. Walks more naturally than a flat alpine sole and grips on paved parking lots and lodge stairs.

Why Willi's

We've been fitting boots in Pittsburgh for over 50 years and boot fitting is where we earn our keep — heat-molding, liner fitting, footbed work, cuff alignment. Stop in at any of our three locations or at our shop at Seven Springs and we'll get these dialed in right.