Field and Trek boot advice

This is the text off their website (Mark W emailed the link to this some weeks ago but thought it might be useful to see here also). Scares me just reading it!

Boot Grading & Crampon Compatability
Torsional Rigidity: What keeps you upright on steep ground?
Boots flex, to verying degrees, as you walk. But did the midsole also flexes or twists along its length. This is called torsional rigidity.

To explain this: hold your boot at toe and heal and try to twist it. A standard walking boot (B1) will twist to a reasonable amount where as a mountaineering boot (B3) will twist very little or not at all.

Now imagine that you want to traverse a steep ground or cross an angled frozen snow slope. In a B1 boot you have a far greater chance of going over on your ankle when standing with your body weight on the inner/outer edges of your boots. Using a B3 boot which won't flex as much means will give a far greater feeling of security.

A B2 boot will have a measure of torsional rigidity; and in general terms, it is the ideal type of boot for most conditions encountered when walking in the British hills. This will include winter conditions where you may have to deal with gentle snow slopes.

The potential for a fatal injury when wearing crampons is magnified if you do not match the Boot Grade with the Crampon Grade: do not be mislead by what some Gear Review guru’s have to say in the walking magazines, our technical guide is based around what the manufacturers recommend. A B3 boot can be used with a C1, C2 and C3 crampon, a B2 boot is compatible with C1 and C2 crampons only and a B1 boot can only be used with C1 crampon.

Boot Grading: As the manufacturers explain it
B:0 (Walking Boots)
These boots are unsuitable for use with crampons.

B1: (Hillwalking Boots)
Suitable for the easiest winter conditions. Flexible walking crampons with a strap attachment (Crampon Grade C1) can be used for limited periods or in emergencies, for example when crossing a patch of snow or ice, rather than for a full day's walk using crampons.

B2: (Mountaineering Boots)
All boots within this range are compatible with articulated crampons with straps or a combination of strapped front and clip-on heel (Crampon Grade C2) for winter mountain walking or glacier traverses.

B3: (Climbing & Mountaineering Boots)
These boots have fully stiffened soles and are compatible with articulated or fully rigid crampons with strap or clip-on systems (Crampon Grade C3).

Crampon Grading
C1:(Compatible with B1, B2 & B3 boots)
With a 8 or 10 point style, this general winter walking crampon has the toe and heel sections connected by a flexible bar. Because of the flexibility along its length it will accommodate moderately stiff hillwalking boots that flex as you walk. Flexible crampons may be used on stiffer boots but should not be used on any boot than flexes to a greater extent than the crampon can accommodate.

C2:(Compatible with B2 & B3 boots)
Designed for mountaineering and mid-grade snow and ice climbing, these usually are a 10 or 12 point crampon with the heel and toe sections joined by either an adjustable (but rigid) bar or by a simple hinge. It is extremely important that the shape (both in plan and profile) of articulated crampons accurately matches the sole of your boots.

C3:(Compatible with B3 boots only)
Specifically for technical and difficult steep ice with 12 points and sometimes featuring a mono-point at the front, C3 crampons are fully rigid along their entire length. As such they must only be used with a boot whose sole is completely rigid, as the crampon cannot flex to accommodate distortion in the sole. The plan and profile of the crampon must match that of your boot.

Boots in the B3 category are ideal for C3 crampons and will also take C2 and C1 types. At the other end of the spectrum a B1 boot should only be used with a C1 crampon. N.B. For the relevant grading of your boots please see the appropriate column in the technical information.

This information is by no means a substitute for experience and correct training in the use of the equipment discussed. Furthermore, please realise that your crampons will require 'fitting' to your boots before use to make sure they match correctly and securely.