What is the B rating?
Mountaineering boots come in three ratings: B1, B2 and B3 – these mainly refer to how suitable the boot is for different activities and how ‘stiff’ the boot is, and therefore which crampons will work.
B1: All-round four season walking boots
These are designed for long days and a small amount of winter hill walking, they will have a stiffened midsole and often feature reinforced uppers or rubber rands and are compatible with C1 crampon only.
B2: Boots for long days in snowy conditions
The midsole and the upper will be stiffened on these boots whilst maintaining a small amount of flex. This allows comfortable walking even if not using crampons. As a general rule, the reinforced upper will add more warmth to the boot than you may find in a B1. These boots can be paired with C1 or C2 crampons.
B3: Technical mountaineering boots
With the stiffest all-round construction, B3 rated boots are designed with technical mountaineering and mixed/ice climbing in mind. There are a wide range of designs from lightweight, technical, climbing boots to double layer, plastic, high-altitude versions and can be paired with the full range of crampons, i.e. C1, C2, C3.
B0: Not suitable for Crampons
Normal hiking boots are occasionally referred to as B0 as they are not suitable for use with crampons. Even with flexible linking bars, crampons will not be able to flex as much as these boots and consequences can be brutal.
How do crampons & boots work together?
As boots are rated B1, B2 or B3, crampons have a rating system of C1, C2 or C3 which also refers to flexibility. As a rule, your boot rating should match or exceed the rating of your crampon. So:
B1 boot – Should only be used with C1 crampons.
B2 boot – Can be paired with C1 or C2 crampons.
B3 boot – Can be used with C1, C2 or C3 crampons.