What does it mean if a shoe has a “soft rubber” or “hard rubber” on the outsole? Newer climbers may not have a rubber preference yet, but whether you are buying your first pair of shoes or are a veteran climber trying to find the perfect shoe after your favorite pair was discontinued, it is important to understand the different kinds and thicknesses of rubbers used on climbing shoes. We hear so often about “soft rubber” and “hard rubber” shoes from vendors and climbers alike, but what do these phrases mean, exactly? Do they even exist? Let’s clear up some misconceptions about climbing shoe rubber and talk about why it’s important to pay attention to climbing rubber.
Most of the time, when we talk about “soft” and “hard” rubbers, we are really talking about the firmness of the rubber type paired with the thickness of the rubber. The firmness of the rubber is going to depend on what type of rubber the manufacturer used while the thickness of the rubber is a choice made according to what kind of performance they want the shoe to have. Let’s see how these relate to the type of rubber and the thickness of the climbing rubber.
Types of Rubber
Different climbing shoe companies are going to use different kinds of rubber to make their shoes, but every climbing shoe on the market is going to utilize what we call “sticky rubber.” Sticky rubber certainly lives up to its name. It not only provides enough friction to keep our feet on small holds, but the rubber is durable enough to withstand months of climbing before being worn out. Remember, the “hard” or “soft” feel of climbing rubber comes, in part, from the firmness of the rubber used. While we could provide an exhaustive list of different companies and their climbing rubber choices, just remember that they all perform a little bit differently. To truly feel the differences, you’ll have to climb in different shoes with different types of rubber. So keep an eye out for shoe demos at your local gym or crag. In the meantime, here are a couple of things to keep in mind about rubber types.
Shoes with firmer rubber are going to have a good edging ability and will provide you with a bit more support to climb for longer periods of time. Firm rubber also tends to be a more durable rubber, allowing for less wear across longer and more frequent climbing sessions.
Rubber with More Give
Shoes with less firm rubber, or with rubber that has more give, are going to provide some more sensitivity to the climber. These shoes will be able to grab onto small features in the rock where firm rubbers may not. Also, rubber with more give will likely have less durability but allow for more aggressive climbing.
Climbing shoe rubber can be anywhere from 3mm to 6mm thick and you would be amazed at the difference just 1mm of rubber can make on a shoe. 3-4mm of rubber is generally considered to be thinner while 4-6mm is considered to be thicker.
When we think of “soft rubber” climbing shoes, we are most often thinking of climbing shoes with thin rubber. Thinner rubber allows for much more sensitivity and is the go-to choice for many advanced boulderers as it allows them to feel small footholds and pull with their toes, creating more friction and keeping them on the wall. On the downside, thin rubber can be pretty quick to wear out, especially for climbers that are still honing their footwork skills. Toe-dragging across the wall will take days of life off of your thin rubber shoes, so they are generally not recommended for beginners. Competitive climbers and slab climbers alike also prefer thin rubber as these shoes generally have more flex allowing for effective smearing.
When we think of “hard rubber” climbing shoes, we are usually referring to shoes with thicker rubber. These shoes are going to feel stiffer, providing extra foot support for longer climbing days. While often more comfortable and more durable, thick rubber shoes will not have the sensitivity or high-performance capabilities of thin rubber shoes. Most beginner shoes will be made with thicker rubber. We suggest starting with thicker rubber and working your way to thinner rubber as your footwork improves.
Hopefully, we have cleared up what climbers mean when they say “hard rubber” versus “soft rubber” and give you the tools to find a shoe with a climbing rubber that works for you. At the end of the day, you need to find a shoe that fits properly and works for the kind of climbing you want to do. Remember to think about shoes in terms of rubber type as they vary from brand to brand, but also in terms of the rubber thickness. These two attributes will contribute to the feel of the shoe as “harder” or “softer” as well as the sensitivity and durability of the shoe. Let us know what your go-to climbing shoe is in the comments below!