Ski Boot Sole & Ski Binding Compatibility Guide

The interface between ski boots and bindings is the single greatest factor in the safety of your ski setup. The job of any pair of ski binding is to keep your boot securely attached to your ski until just before the point where it could injure your knee or leg. To accomplish this companies have come up with a variety of different ski boot sole standards, and binding designs that work together to provide consistent and safe release. These different standards exist because of the different intended uses for boots, from inbounds riding to alpine touring. 

Not all ski boot are compatible with all ski bindings. Using a setup with non-compatible bindings means that your skis cannot be guaranteed to release properly, creating the potential for dangerous pre-releases and serious injury. That is why it is important to make sure your ski boots and bindings are compatible and safe. So we’ll be breaking down all the different boot standards on the market, what they mean, and what they’re compatible with.

It’s important to remember that ski boot sole and binding standards are broad universal statements, but in real world use, the specifics of your own equipment can vary. Wear and tear on boots and bindings can cause them to fall out of adjustment, and perform outside the standards the manufacturer intended. Because of this, it’s important to get your boots and bindings adjusted and regularly release tested by a qualified ski shop before you use them. 
 

Ski Boot Sole & Binding Compatibility Chart
Ski Boot Sole Norms
Ski Binding Norms
Boot & Binding Terms Glossary

 

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Ski Boot & Binding Compatibility Chart

	Alpine Bindings	GripWalk Bindings	MNC Bindings	WTR Bindings	Sole.ID	Tech/Pin Bindings
ISO 5355 - Alpine DIN Soles	✓	✓	✓	✓	✓
ISO 9523 - Touring Soles			✓*
GripWalk		✓	✓	✓	✓	✓¹
Walk To Ride (WTR)			✓	✓	✓**	✓¹
Non-Compliant Touring						✓

1. Must have tech touring inserts

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Ski Boot Sole Standards and Trade Names

There are five main ski boot sole types available out there, each with a different designation and dimensions that are designed to work in specific types of bindings. It's important to note the difference between a true ISO standard, like ISO 5355, and a brand-name sole like GripWalk. An ISO boot sole standard ensures proper testing and safety of boots and bindings, while trade names like GripWalk, WTR and MNC are coined by brands for soles they manufacturer that have been certified as compliant with one or more of those ISO standards.

ISO 5355 Alpine (DIN) Soles

The most common boot sole norm for inbounds ski boots is ISO 5355. This sole is often called the “DIN” sole, or the “alpine” sole. It’s designed with hard plastic under the toe and heel to allow for smooth, consistent releases from alpine bindings. It doesn’t walk as well as norms with rubber soles, or rocker, but ISO 5355 soles will work in a huge variety of bindings including traditional alpine bindings, WTR bindings, and GripWalk Bindings. It’s important to note that the standards for ISO 5355 stipulate that the boot cannot have tech fittings. So while some boots on the market have the same shape sole as an ISO 5355 boot, if they have tech fittings they’re not strictly indemnified to work in pure ISO 5355 bindings (but will work in Gripwalk and MNC bindings).

ISO 9523 Alpine Touring Soles

The second main sole standard is ISO 9523. This is a pretty broad standard, developed for touring boots with sticky rubber and rockered soles. These boots can have tech fittings, and will walk much better on hard surfaces. Most touring boots meet the ISO 9523 standard.
Within this broader standard are two subsets: GripWalk and WTR. Both GripWalk and WTR designated boots meet the ISO 9523 standard, so they’ll work in any binding designated to work with ISO 9523 boots. However, not all ISO 9523 boots meet the GripWalk or WTR standards, so they won’t work in those bindings.

GripWalk Soles

GripWalk has evolved rapidly over the past several years and are now featured on a huge variety of boots. Featuring a slightly rockered sole, many inbounds and “crossover” (inbounds/touring) boots are now coming with GripWalk soles because they offer a very consistent release pattern, but offer a lot more traction and a more natural stride. GripWalk soles are compatible with MNC, ISO 9523, WTR, and GripWalk certified bindings. They are not certified for standard alpine, ISO 5355 bindings. Ski boots with GripWalk soles can have tech fittings, but do not always have them.

WTR (Walk to Ride) Soles

Like GripWalk, WTR soles were meant to bridge the gap between the pure alpine ISO 5355 standard, and the touring ISO 9523 standard. They offer a consistent release pattern, and more traction and sole options than pure inbounds boots. However, in recent years, GripWalk has superseded WTR as the main accepted norm on crossover boots. WTR ski boots are compatible with WTR certified bindings, MNC bindings, and ISO 9523 bindings. They are not compatible with standard alpine ISO 5355 bindings or GripWalk labeled bindings. WTR boots can have tech fittings, but do not always.

Non-Compliant Touring Boots

Many fast and light touring boots fall outside of those four main standards. In the interest of touring efficiency they have shorter, more rockered soles, smaller toe and heel lugs (or no lugs at all), and other non-standard shapes. These boots do not meet the ISO 9523 touring standard, instead their tech fittings fit the universal tech binding standard. These non-standard boots should only be used in low tech (pin) bindings. They will not work with any of the bindings mentioned above, and if they are made to fit into these bindings they will be inconsistent and dangerous.
 

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