What is the difference between ISO 5355 and GripWalk?

ISO 5355 is the standard for a flat alpine boot sole. GripWalk, now ISO 23223, is a different sole shape, rockered and fitted with rubber lugs, so you can walk more naturally. A GripWalk binding also accepts ISO 5355 soles, but an ISO 5355-only binding is not guaranteed to accept a GripWalk sole. Look for GripWalk on the binding's own compatibility list.

Can a boot be both GripWalk and tech?

Yes. GripWalk describes the sole; tech describes the metal inserts in the toe and heel. They are separate features, and some boots have both. That is why we list a boot's standards as a set rather than a single value.

Does a matching standard guarantee a boot fits a binding?

No. A shared standard means the specs overlap. Fit also depends on the binding's adjustment range, your boot sole length and the manufacturer's current compatibility notes. Confirm with the manufacturer or a binding technician before mounting.

BootsSki

Ski Boot Sole Standards: ISO 5355, GripWalk, Tech and MNC

By Luke Judge · Published October 2, 2026

Key facts

ISO 5355 is the alpine boot sole norm: a flat sole that alpine bindings are built around
ISO 9523 is the touring sole norm: a rockered sole with a rubber tread, made for walking; GripWalk is a rockered, rubber-lugged sole and is now an ISO norm, ISO 23223; the binding must be listed as GripWalk-compatible; Tech compatibility is a boot-side feature (toe and heel inserts) that pin bindings clip into; it is separate from the sole norm; MNC (Multi Norm Certified) bindings are TÜV-certified to accept alpine (ISO 5355), touring (ISO 9523), GripWalk (ISO 23223) and WTR soles; not tech inserts; One boot can carry several of these at once, such as GripWalk plus tech inserts

A ski boot and a ski binding have to agree on one thing before anything else: the shape of the boot sole. The sole standard decides whether a boot can sit in a binding at all. The names are confusing because they describe different things. Some are formal norms, some are brand-led sole designs, and one is a feature of the boot's inserts rather than its sole.

This page is a plain reference for those terms. The product pages for ski boots and ski bindings on SnowSift use the same terms in their spec panels and list the verified products whose published standards overlap.

ISO 5355: the alpine sole

ISO 5355 is the international norm for alpine ski boot soles. The sole is flat and the toe and heel lugs are shaped to sit in an alpine binding's toe piece and heel piece. A boot built to ISO 5355 is the baseline that resort bindings are designed around. On SnowSift this appears as "Alpine (ISO 5355)".

ISO 9523: the touring sole

ISO 9523 is the norm for touring boot soles. The sole is rockered and carries a rubber tread, so the boot can walk, hike and climb. It is built for bindings that accept a touring sole. On SnowSift this appears as "Touring (ISO 9523)".

GripWalk and WTR

GripWalk is a sole with a rockered shape and rubber lugs, so it grips and rolls when you walk. It is now an ISO norm, ISO 23223 (adult "A", child "C"). It is not the same shape as an ISO 5355 sole. A GripWalk binding also accepts ISO 5355 soles, but an ISO 5355-only binding is not guaranteed to accept a GripWalk sole.

WTR (Walk To Ride) is a Salomon/Atomic-led format with no ISO norm of its own, so check the binding maker's list for it.

Tech inserts

Tech (pin) bindings hold the boot with two pins at the toe, which lock into metal inserts in the boot. Boots with those inserts, and often matching heel fittings, are called tech boots. This is a feature of the boot's inserts. It does not replace the sole norm: a tech boot also has some sole shape, such as touring or GripWalk. See backcountry binding standards for how pin bindings compare with frame and MNC bindings.

MNC: Multi Norm Certified

MNC stands for Multi Norm Certified. Salomon, Atomic and Armada use it for bindings TÜV-certified to accept alpine (ISO 5355), touring (ISO 9523), GripWalk (ISO 23223) and WTR soles. It does not cover tech inserts. Check the manufacturer's list for the exact model.

How SnowSift lists compatibility

Each boot and binding page shows the sole standards we have for that product. A boot can have several, for example GripWalk and tech. Below that, the page lists verified products in the catalogue whose standards overlap, ordered by brand and then name. It is a lookup of published specs, not a recommendation and not a fit guarantee. Where a manufacturer does not publish a standard, the field stays empty rather than guessed.

Frequently asked questions

What is the difference between ISO 5355 and GripWalk?: ISO 5355 is the standard for a flat alpine boot sole. GripWalk, now ISO 23223, is a different sole shape, rockered and fitted with rubber lugs, so you can walk more naturally. A GripWalk binding also accepts ISO 5355 soles, but an ISO 5355-only binding is not guaranteed to accept a GripWalk sole. Look for GripWalk on the binding's own compatibility list.
Can a boot be both GripWalk and tech?: Yes. GripWalk describes the sole; tech describes the metal inserts in the toe and heel. They are separate features, and some boots have both. That is why we list a boot's standards as a set rather than a single value.
What does MNC mean on a binding?: MNC stands for Multi Norm Certified. Salomon, Atomic and Armada use it for bindings TÜV-certified to accept alpine (ISO 5355), touring (ISO 9523), GripWalk (ISO 23223) and WTR soles. It does not cover tech inserts. Check the manufacturer's list for the exact model.
Does a matching standard guarantee a boot fits a binding?: No. A shared standard means the specs overlap. Fit also depends on the binding's adjustment range, your boot sole length and the manufacturer's current compatibility notes. Confirm with the manufacturer or a binding technician before mounting.

SnowSift is independent: we cross-check every spec against the manufacturer source and rank retailers by price, never by commission. How we match products & verify specs.