How Climbing Shoes are Made

The process of making a climbing shoe takes many steps, all of which are performed by hand. We cover the building of a shoe from the original shape idea to the sole.

There are 2 main methods to make climbing shoes: slip-last and board-last construction. Slip-lasted shoes are by far the most common today, with only a handful of manufacturers still producing board-lasted shoes.

The rule-of-thumb: Board-last construction creates a relatively stiff, supportive shoe and is reserved for flat, comfort-oriented kicks. Slip-last construction on the other hand can be used to create any style of shoe from a noodle-soft slipper to a high top stiff enough to rival a board-lasted shoe.

Although a flat and stiff shoe can be either board or slip-lasted, a soft or aggressively downturned shoe is the exclusive realm of slip-last construction.

The Last

Every climbing shoe is built around a hard plastic last (typically high-density polyethylene) that dictates the shape and overall fit of the shoe. The last is a mold that determines the heel width, instep height, forefoot width, toe box depth and shape, overall volume, and the degree of downturn and asymmetry.

Last shapes can vary greatly. The last for a flat, comfort-oriented shoe mimics the natural shape of the human foot. Conversely, an aggressively downturned, highly asymmetric last, can look more like an eagle talon than a foot. And each size of shoe has its own left and right last. The last shape is one of the most critical parts of the shoe design.

Lasts are also the most secretive part of a climbing company. This can be very frustrating for climbers because it makes it harder to know what the last shape is that best fits your foot. Some companies do share an overview of the last shape or give letter abbreviations to certain lasts so you can which shoe models are similar.

Some companies use the same last for male and female shoes, which means the difference between the models will be minimal. Other companies have different shaped lasts for male and female models, and those shoes often fit larger and smaller volume feet better. SCARPA has one of the largest number of different lasts of any climbing shoe company we know about.

Slip-last Construction

With a slip-lasted shoe, the footbed is sewn onto the pre-assembled upper (that includes the closure system and tongue) to form a sock-like shape. This sock is then slipped onto the hard plastic last (hence the name slip-last), which stretches the upper into the correct shape. Slip-lasted shoes then get a specifically shaped midsole to increase stiffness exactly where desired. The rubber rand and sole are then glued onto the upper/footbed assembly.

Once the upper is stretched onto the last, the next step is gluing the midsole. This is where support is focused into specific areas by adding various materials to key locations across the shoe. All of the tech that goes into ‘what a shoe can do’ really starts to take hold here, as the maker can provide support or allow flex right where they want it. For example, a stiff, flat shoe made for edging or jamming might have midsole support all the way across the forefoot, where a shoe made for overhanging delicate toeing may use smaller sections of different materials to create areas of different stiffness to dial flexibility and sensitivity.

The materials used can vary from patches of synthetic fabric, thin foams or rubbers, or even molded polycarbonate plastic or bits of carbon. Many of the highest tech performance shoes mix several materials and shapes for maximum control.

Next, randing and additional rubber parts are glued on including toe patches and molded heel cups. Much of the zone specific tensioning of shoes happens at this step, where skilled cobblers pull and twist the shoe to dial resistance and flex in certain areas, depending on the type of climbing a shoe is designed for.

An all-day shoe will have very little tension in the randing, for example, just enough to keep the shoe against the foot without fatiguing your muscles. This makes the shoe comfortable for all day wear, but less tuned for things like toeing and hooking.

Conversely, a highly aggressive or downturned shoe will have several areas of metered tension provided by this gluing and stretching to provide support or flexibility in various areas. This allows cobblers to maximize power for toes and heels while maintaining the exact amount of flex and twist in the arch. How your shoe feels on your foot while you climb has a TON to do with this step.

Finally the sole is glued down. This step allows for the final tensioning and is where the cobbler commits the final shape of the shoe. A highly tensioned shoe might be a bit of a banana until it is attached to the sole piece, where it is settled and held into its final shape.

Many cobblers now include a high pressure press and curing phase at this point, to make sure everything stays put and the glue has ample time to cure. This can be as long as several days depending on the glue and amount of gluing steps.

Finally, a skilled cobbler takes the shoe to a grinding wheel, where the final profiling of the edges is done, and any areas where rubber materials mate up is smoothed and finished. This provides a chance for final assessment of the intended look and shape of the edge before the shoe is packed up and shipped out.

To see the process in action, check out this video that shows the process of building Mad Rock’s Flash 2.o slip-lasted shoes

Board-last Construction

Board-last construction is the traditional method of making approach shoes, mountaineering boots, and most shoes in general PLUS it’s still used in the construction of some climbing shoes. It is not as common today due to the lack of versatility it offers.

In board-lasted shoes, the footbed is glued to the full-length midsole (the board). This midsole is then temporarily attached to the bottom of the last (the plastic mold) to keep it firmly in place.

Next, the pre-assembled upper is slipped over the top of the last. The upper is then tightly wrapped over and around the edges of the midsole and glued in place to make the midsole an integrated part of the shoe.

At this point, the shoe is in a similar state to a slip-lasted shoe: The upper is connected to a footbed, enclosing a last. The biggest difference here is the stiff midsole of the board-lasted shoe is what secures the footbed, while the slip-lasted shoe has no midsole (yet) and the footbed is sewn directly into the upper. The rand rubber and sole are then glued onto the upper/midsole assembly.

Below you can see how you can quickly tell between a board-lasted shoe and a slip-lasted shoe.

A few examples of board-lasted shoe models:

Although few climbing shoes are made using board-last construction these days, many other climbing-related shoes use this method, including approach shoes and mountaineering boots.

This video from Scarpa clearly shows the difference between slip-last and board-last construction with approach shoes, and it’s the same process for climbing shoes. We’ve queued the video to 1:06 where they detail the construction types. The video goes on to explain direct-attach construction (beginning at 3:03) which is not used for making climbing shoes.

Summary

Regardless of lasting method, aggressiveness, or comfort, climbing shoes are almost entirely made by hand (and is partly why climbing shoes are expensive). Yes, there are some steps that utilize machinery but the critical parts of the process, specifically the tensioning of rand rubber, is completely done by hand, one at a time. At the upper end of the climbing shoe performance spectrum, this requires extreme skill.

Slip-last construction has enabled the use of a wide variety of midsole designs and materials, from soft to stiff, minimal to full-length, and everything in-between. There are very few limitations as slip-lasted shoes can be shaped to any design.

Today board-lasted construction is seen more in approach shoes, mountaineering boots, and only a few high-top climbing shoes.

Ultimately, these construction types only refer to the process by which the shoe is made and are not a foolproof way to determine a shoe’s performance characteristics. It’s more just interesting to note the nuances of construction versus make a buying decision for one vs the other.