Climbing Shoe Technology Explained

What’s in a Sole? Laces or VCR? Why is Asymmetry Important?

Do I Need a Downturn and Pre-Tensioning?

What do downturn and slingshot mean, is soft or hard rubber better, and what does the midsole actually do? When you’re looking for new climbing shoes, discuss your gear at the crag, or chat to others in a gym, you’ll find yourself confronted with all sorts of specialist climbing shoe jargon. This is because even though climbing shoes might seem to be simple products with a little rubber, some leather, and a pair of laces, hours of research and development work actually go into every single model. The right technological solutions and designs for the specific use have to be optimally coordinated to offer you the perfect weapon for your next successful climb.

A climbing shoe is made up of the following elements:

To understand your climbing shoes’ many features and the technologies that bring them to life, it is useful to take a look at the structure of a climbing shoe and see the names of the individual parts.

The great art of developers and designers lies in precisely combining and coordinating the various different materials and structures. In an ideal world, a climbing shoe should be able to do everything. As not everything is possible or useful though, we focus on creating the perfect balance between specific properties. In other words, we optimize every shoe for its specific purpose.

The right rubber compound for climbing shoe soles

Rubber compounds and their formulations are one of the best kept secrets in the climbing shoe industry. They are developed through weeks and months of research and fine tuning. After all, the rubber has a major impact on climbing shoes’ properties and ultimately on your performance on the wall.

Together with the midsole, the sole determines how soft and sensitive or hard and supportive a shoe is. As with many things, there is no all-round perfect solution. This is because a compound can be ideal or utterly useless depending on the requirements of the specific route or problem that you’re facing.

In addition to extremely soft and hard versions, there are also rubber compounds that offer a good balance with different focuses. An all-rounder is not too soft, not too hard, and has good friction properties. Harder, more durable compounds that don’t wear as quickly and therefore retain their shape for longer are beneficial for continuous use in gyms, for example for rental use or long training sessions.

The Red Chili collection features the following rubber compounds, which are tailored to the requirements of the various climbing and bouldering uses: 

  • Vibram XS Grip 

    Vibram XS Grip 

    With the XS Grip rubber compound, Vibram offers an outsole that has been specially tailored to the requirements of ambitious climbers and boulderers. It generates impressive levels of friction while also allowing great sensitivity when stepping.

  • Red Chili RX-1 ALLROUND 

    Red Chili RX-1 ALLROUND 

    The name says it all with the RX-1 ALLROUND sole. This offers a particularly good balance of friction, sensitivity, and edge stability.

  • Red Chili RX-2 TECHGRIP  

    Red Chili RX-2 TECHGRIP  

    The RX-2 TECHGRIP is the perfect choice for anyone looking for greater edge stability. This offers just the right rigidity and provides ideal support when standing on small ledges.

  • Red Chili RX-3 ENDURANCE  


    Red Chili RX-3 ENDURANCE

    When durability is required, the RX-3 ENDURANCE comes into play. The rubber compound is characterized by outstanding durability and high abrasion resistance. Coupled with the light gray color of the rubber, which leaves far fewer visible marks on climbing walls, this rubber is primarily ideal for rental shoes and shoes subjected to above-average levels of strain.

What's in a midsole? 

Between the outsole and the footbed is another important element that works closely with the former and affects the performance of a climbing shoe: the midsole.

The combination of the midsole and the outsole with an appropriate rubber compound determines a climbing or bouldering shoe’s rigidity, supportiveness, edge stability, and sensitivity. It can also help to generate more tension in the shoe.

The Red Chili collection features the following midsoles:

  • Red Chili RC-SENSE

    Red Chili RC-SENSE

    The Red Chili RC-SENSE is a recessed forefoot midsole that only provides support along its edges. What makes it truly ingenious is that this solution offers greater edge stability to even very soft shoes while still retaining maximum sensitivity in the midsole area. We currently use this midsole in our ultra-soft SENSOR model. 

  • Red Chili RC-PRECISION 

    Red Chili RC-PRECISION 

    This minimalistic midsole can be found at the edge of the big toe, where it provides localized support. The RC-PRECISION is used to provide a little more support in our performance-oriented PUZZLE model for children and adolescents, which is generally very soft. 

  • Red Chili RC-FLEX 

    Red Chili RC-FLEX 

    We have used CAD software to optimize the RC-FLEX midsole to meet our athletes’ needs. We primarily work in the central area here with vertical cuts in the midsole. This enables us to achieve great sensitivity, which is important when stepping on volumes and for smearing. At the same time, the midsole offers maximum support around the edges so wearers can cleanly stand on small ledges. The result is a midsole that is suitable for all kinds of high-end climbing, from precise edging through extensive smearing to parkour bouldering.


  • Red Chili RC-TENSION 

    Red Chili RC-TENSION 

    The RC-TENSION was specially developed for our VOLTAGE range. It offers optimum support when standing on small footholds and on overhanging routes. As it allows slightly less flexibility than the RC-FLEX, it relieves strain from the forefoot more holistically. It is ideal for precise climbing and longer, ambitious routes where the feet need more support.  

  • Red Chili RC-SUPPORT 

    Red Chili RC-SUPPORT

    The RC-SUPPORT is a midsole that runs the full length of the shoe. It is the most supportive midsole in the Red Chili collection and is primarily used in the models in the COMFORT and PERFORMANCE ranges. Its properties are particularly popular with all those who love a firm-fitting shoe regardless of the footholds they are climbing.

How the tension systems work

Welcome to the next level of specific climbing shoe technology: tension systems. Climbing shoes need tension to transfer power to the toes. It also provides stability and a firm fit, important for clean, powerful footwork. Tension is achieved through the interplay of different forms of workmanship, which are carefully coordinated to achieve the best performance for the desired use.

1. The asymmetry of climbing shoes 

If you look at a climbing shoe from above, you’ll see just how much the tip is offset from the straight line that runs between the middle of the heel and the midfoot. The greater the variation, the more asymmetrical the shoe. Pronounced asymmetry increases the tension on the inside and the power transmission to the big toes. It provides precision and stability, but also compromises on comfort. Asymmetry is primarily used for shoes in the HIGH-END and PERFORMANCE ranges to generate additional tension and a firmer fit. At the same time, asymmetry can promote extremely precise stepping on small ledges and offer the necessary tension to a particularly soft shoe with a minimal midsole. A neutral model is recommended for crack climbing as an asymmetrical shape allows less contact with the rock surface and makes it harder to jam the foot in cracks.

The Red Chili collection features the following styles:

2. What is the downturn in a climbing shoe? 

The downturn describes the extent to which the forefoot area is tilted downward. The greater the downturn, the more power is transferred to the toes, facilitating heel hooks and making it easier to stand on small footholds in overhanging terrain. On very steep terrain in particular, the curved shape makes it possible to hook or hold distant footholds with less energy and effort than with a very flat shoe. A soft shoe with a downturn is not particularly suitable for small footholds on verticals; in such cases, a flatter model with a somewhat harder sole is a better choice.

3. What is pre-tensioning in a climbing shoe? 

Pre-tensioning is achieved by the localized use of clamping rubber. This can run along the side, under the foot, diagonally, or round the heel toward the front. When using a slingshot, for example, the clamping rubber runs round the heel and toward the front. If the slingshot ends under the midfoot, it primarily provides a securely fitting heel. On the other hand, if the slingshot continues all the way to the forefoot, the entire foot is primarily pressed forwards into the toe box to encourage power transfer to the toes.

Red Chili makes the following differentiations:

What materials are found in climbing shoes?

Your climbing shoes are not only made up of rubber and the midsole, but also several textile elements: the upper, the tongue, the lining, and the footbed.

The upper: suede leather, microfiber, or a mix of the two

Suede leather offers the major advantage of being adaptable and having an accordingly pleasant feel. Climbing shoes with a high proportion of leather are therefore a good choice for anyone whose feet do not get along so well with climbing shoes or have possible malpositions, such as hallux valgus since they can stretch and give way in the problem areas. As a result, leather climbing shoes may expand over time, which you should consider when choosing the right shoe size.

A further benefit is that leather is more abrasion resistant than microfiber.  

Where even the smallest damage to synthetic fabrics such as microfiber can lead to the material separating more and more, with leather only individual fibers are damaged without affecting the surrounding area.

In addition, the suede leather typically used in climbing shoes has a rough surface, which means that the material is comfortable on the skin and adheres well. At the same time, the comparatively low breathability of the material means that you sweat earlier in climbing shoes with a high leather proportion.

Other materials, linings, and footbeds

We also make a conscious effort to use recycled materials, such as in the VENTIC AIR LACE, the textile elements of which are 100% recycled. Special inserts also provide additional functionality, for example in the Red Chili kids’ shoe PULPO, where a neoprene triangle protects the Achilles’ heel from pressure while also providing a secure fit.

As you may have already realized, there are lined and non-lined climbing shoes. With leather shoes, the lining helps make the shoe more dimensionally stable. Lining materials are also used as an extra layer to make the shoe more rigid and comfortable. For example, a footbed made from antibacterial hemp has a pleasant feel and creates a good climate.


Fastening systems: lace-up shoes, VCR shoes, or slippers

There are three different fastening systems: lace-up shoes, VCR shoes, and slippers. There are also hybrid solutions. When choosing the right shoes for you, your personal preferences, the ease of putting the shoes on and taking them off, the desired fit, and, of course, where you want to use your shoes, all play a role. 

  • Lace-up climbing shoes

    The major advantage of laces is their great adjustability. Laces can be tied tightly and adjusted in specific areas, making it possible to precisely adjust the fit and increase the pressure and tension as required. What’s more, tension is distributed more evenly and fewer concentrated pressure points arise. This provides a secure fit and the necessary safety for precise, intricate footwork. The system has a flat form that makes it ideal for crack climbing. The disadvantage is that shoes take longer to put on and take off.


  • Slippers

    Slippers are a fair bit quicker and easier to put on and take off. They often have an aggressive shape and are very tight when first purchased as they cannot be adjusted with a fastening system to guarantee a secure fit. Some slippers have a VCR strap to make them more adjustable.



  • VCR climbing shoes

    VCR climbing shoes are extremely popular. They can not only be opened wide to enable them to be put on and taken off easily but also adjusted. There are various fastening solutions involving one, two, or three parallel straps or two or three opposing VCR straps. More VCR straps enable more localized adjustment.

  • Climbing shoes with hybrid fastening systems

    You’ve probably also seen shoes that use a combination of both laces and VCR. There are various different solutions in this regard. With the Red Chili MYSTIX, the crossed, flat webbing straps can be individually adjusted with a quick tug and secured with a VCR strap. The FUSION also combines the benefits of VCR and laces. Here, we use extremely strong and abrasion-resistant Technora aramid fibers that come from our own production department. The production left-overs from these paragliding lines are the perfect length for being given a useful secondary purpose as climbing shoe laces instead of simply being disposed of as waste.

Further elements of a climbing shoe 


The rand surrounds the foot, providing protection, edge stability, and thus general stability and strength. Depending on the intended purpose, thinner or thicker rubber is used. A thicker layer of harder rubber makes the shoe more stable and durable; a thinner layer of soft rubber increases the sensitivity. In our CHARGER, SESSION, and SESSION AIR shoes, for example, we use a double rand in the toe area, even with an indicator of when the shoes need resoling. A tip on fit: the greater a shoe’s rubber content, the more stable its shape, i.e. the less it will give, so the better it needs to fit.

Toe patch

As you have probably already realized, there are also shoes with different-height rands in different shapes, some of which are supplemented by toe patches. The rubber on the top of the toe box makes it easier to cleanly place and securely hold toe hooks.


Some shoes also have an EVA foam wedge under the heel. This cushions forces when landing and encourages an upright position. It also makes the shoes more comfortable to wear on long routes. The ‘impact zone’ can be found in Red Chili’s SPIRIT and SPIRIT LV models.


Robust loops make it easier to put shoes on and take them off. They can also be used to hang shoes on a climbing harness on multi-pitch climbs. Our rental shoes also come with press studs on the pull-on loops so the left and right shoes can be cleanly attached for storage, saving a lot of time when issuing shoes.