Performance Midsoles

30 Dec.,2024

 

Performance Midsoles

Selection, Performance, Care, and What to Look For

Meindl has been building exceptional footwear for over 300 years only using premium materials to make our boots best in class. Whether that is using Gore-Tex® waterproof membranes, Vibram® outsoles, premium insulation, etc. to make sure our boots perform no matter the condition you are in. When purchasing boots these are all technologies you, the customer, have been educated on, and for good reason. Your feet deserve the best and your boots should not be a piece of equipment you have to worry about while at the top of the mountain. When doing your research on what the best boot is for you, how many of you have heard of the midsole and how important this layer of the boot is for your feet as well as the life of the boot? We feel by not educating our customers on the midsole, we are not giving you the proper tools to make the best decision on your next purchase. 

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What is a midsole? This is the layer of material between the inner and outer soles of a shoe. The midsole of your boot/shoe absorbs shock and adds a layer of protection, structure, and support between your feet and the ground. 

When it comes to midsoles there are two main materials used when constructing high performance footwear, like you'll find at Meindl - EVA (ethylene vinyl acetate) and Polyurethane (PU). Each material is used for different reasons and purposes, and it all comes down to the end use for each specific boot. What is the terrain the boots are built for? What are the elements the boots will primarily be used in? Just to name a few. Like any material used there are the extreme benefits that each material provides, but there can be potential downsides as well. 

Materials

EVA (ethylene vinyl acetate) is the most common material used in footwear midsoles. You will find EVA in all styles of footwear from alpine boots to walking shoes. EVA is a lightweight foam material made up of thousands of compressed bubbles. Each bubble is filled with gas that makes it lightweight as well as provides excellent cushioning and shock absorption for your feet. What makes EVA so popular in the footwear industry? EVA is extremely compressible and can be easily manipulated during the manufacturing process. Whether you need a high-density EVA for an alpine boot a low-density EVA for a walker you can use the same material. 

Pros of EVA

When it comes to using EVA there are some advantages and specific reasons why this material is used in performance footwear. EVA is more lightweight compared to PU as well as provides improved flexibility. This is what makes EVA perfect for light hiking and running shoes where you don't want that extra weight. In addition, EVA will absorb more shock from step impact relieving the stress on your joints as you are out on your hike. 

Cons of EVA

As we stated earlier there can be disadvantages to every material used; with EVA the biggest downfall is a relatively short life span. EVA holds a memory, meaning after every step the material will compress and rebound. After thousands of steps, the ability for the EVA to rebound is reduced, resulting in your footwear not having the same cushion and support you have been accustomed to. As that material compresses over time there will not be noticeable defects to the midsole, but your footwear is going to become less supportive and less comfortable, to where they can feel "flat" on your feet. As the EVA loses its cushioning and support it is time to either replace your footwear or if boot allows, have the soles recrafted. Like all materials this is a natural process and the reason many recommend replacing shoes footwear using EVA more often, to ensure you have the proper support needed. 

PU (polyurethane) is a synthetic plastic material commonly used by the best boot makers for midsoles in high performance trekking boots. Polyurethane is a much denser material compared to EVA or other materials used in hunting and hiking boots today. PU is most found in high performing boots (alpine boots), however is becoming more and more popular in mid-range boots as well. The majority of Meindl USA boots today use polyurethane due to the performance as well as how long these boots will last. 

Pros of PU

Opposite of EVA the biggest advantage that PU offers is it does not hold a memory - meaning your midsoles will always rebound back to the same shape and provide the same cushion from day one through the lifespan of that boot. Also, with PU midsoles you are going to have a lot longer life on your midsoles and can get more years and miles with the same comfortable fit compared to an EVA midsole. The density and rigidness of PU provides more lateral support as well as removes almost all possibility of stone bruising in your feet. Simply put, polyurethane is the perfect material for technical boot midsoles. It is flexible, resilient, cushioning, and long lasting. When constructing a high-performance hunting/hiking boot the best midsole you can use for performance is PU. 

Cons of PU'

Just like EVA, PU over time can break down, the only difference is when this happens it is clearly visible to the point where the soles may come off, much more visible than EVA. This is a process called hydrolysis, a gradual deterioration and disintegration that can lead to the midsole detaching from the outsole or crumbling from the inside out. This is a process that occurs over years. With PU (and many other compound materials), moisture will find its way through the smallest of pores and chemical reaction, or breakdown, begins and microscopic cracks occur. Ultra-violet rays of the sun, extreme heat and other factors also encourage hydrolysis, hardening the PU to a point tiny cracks develop. To be clear this is part of the natural process, not a defect in material or manufacturing. When you think of an old set of tires that sit for years, you wouldn't expect those tires to be the same as the first day you got them. Same goes for your PU midsoles. 

How to Extend the Life of Your Midsoles?

With both EVA and PU midsoles it is a natural aging process that results in the midsoles breaking down. As we stated with EVA, the midsoles hold a memory, meaning every step you take results in those midsoles compressing. Other than not wearing your boots/shoes (which is not an option) there is nothing to slow down the process of EVA compressing and becoming less supportive and comfortable. 

Regarding PU midsoles, the best steps you can take to slow down and help prevent hydrolysis from taking place is by WEARING your boots. When wearing your boots, the midsole is getting a workout, flexing in the fresh air as you walk. With the air being worked in and out of the pores it is preventing any moisture from building up inside those midsoles, and therefore, helping prevent hydrolysis from occurring. When you are not wearing your boots, there are a couple critical steps to keep your PU midsoles from breaking down:

  • Store your boots in a dry, cool, ventilated space. Not near a heat source; not in a humid environment. And while in camp, keep them away from the campfire (or any heat source at home). Do not use a hair dryer, heated boot dryer or any heat source to hasten drying. 
  • Keep your boots clean. Clean them regularly, especially after hard use in wet, muddy environments. And for Pete's sake, clean off any mud, manure, or other muck you may have encountered. You don't want to track that in the house anyway. Click here to learn more on how to clean and condition your boots. 

Tips to check for Hydrolysis

With so many variables it is impossible to predict when hydrolysis will advance enough to cause soles to detach. We have well-worn boots we have used for more than a decade that show no outward signs of hydrolysis decomposition. 

  • If you've had your boots for several years, you should inspect them (or have them inspected by an expert). A tell-tale sign that is easy to overlook is fine granular black specks on the floor or shelf where you store your boots. Like we said, easy to overlook because most hydrolysis occurs inside the midsole. Visible specks are a sign of advanced hydrolysis on the outer edges. 
  • If your boots have not been used for years, we recommend you wear them on a test hike or for a few days of everyday wear before venturing far off the beaten path to determine if the soles are solidly attached or if any signs of hydrolysis damage become apparent. 
  • Or you can perform a flexibility test by using a blunt pointed object, like a ballpoint pen with the ink tip retracted, key or similar object, into the midsole. DON'T use anything sharp, no knives, pointed pencils, etc. Push the blunt pointed object into the midsole, which may be easiest found on the heel wedge. The polyurethane should give under moderate pressure and rebound once pressure is lifted. If it has hardened, flexibility on the push in and on the rebound will be limited or nonexistent. 

Once the process starts and your midsole begins to break down, there is nothing you can do to stop it. The good news is, Meindl Boots can be recrafted, and your well-broken-in boots can be given a new life. If you have any questions visit our FAQ page to help answer any additional questions. As always you can give us a call at 1-833-563- or us at . 

 


Rubber vs. EVA Soles for Sandals

Choosing the right sole for your sandals can significantly impact comfort, durability, and overall enjoyment. This guide delves into the specifics of rubber versus EVA (ethylene-vinyl acetate) soles. It provides a thorough analysis to assist you in making an informed decision for your next pair of sandals.

 

The Basics: TL;DR ---

  • Outsoles. The sole of a sandal is the bottom layer that comes in direct contact with the ground, crucial for traction, durability, and protecting the foot.

  • Durability. Rubber soles surpass EVA in resistance to wear and tear, making them more durable and longer-lasting.

  • Cushioning. EVA soles provide superior cushioning and comfort, but sacrifice stability and support in the process.

  • Weight & Flexibility. EVA outsoles are lighter and more flexible than rubber, but rubber balances weight and flexibility with durability.

  • Traction. Rubber outsoles provide better grip and slip resistance on various surfaces, making them a better choice for outdoor and wet conditions.

  • Sustainability. Rubber tends to have less of an environmental impact compared to EVA.

  • Cost. While EVA soles may be cheaper initially, rubber soles offer better long-term value. Their durability makes rubber soles more cost-effective in the long-run.

 

What You Need To Know---

Choosing between rubber and EVA soles for sandals hinges on understanding each material's unique benefits. Rubber soles excel in durability and traction making them perfect for those who value long-lasting wear and outdoor versatility. EVA soles are more suited for light leisure activities.

Rubber soles emerge as the more sustainable and economical choice over time. Understanding the key differences between rubber and EVA will help you find the pair of sandals that meets both your comfort and durability needs.

 Shop Sandals with Rubber Soles

For more information, please visit green eva boots.

Table of Contents

         

        Understanding Sandal Anatomy

        Before we dive deeper into the specifics of sole materials, it's essential to understand the different parts of a sandal. Each component plays a crucial role in the overall functionality, comfort, and durability of the footwear. Here's a quick breakdown of the main parts of a sandal:
        • Straps. These are the parts that hold the sandal on your foot. They are often polyester, nylon, or leather.

        • Midsole (or "Footbed"). This is the layer that your foot rests on. It's designed for comfort and support. Midsoles are made from various materials, including PU, EVA, rubber, or cork.

        • Top Cover Material. The midsole is sometimes topped with an additional material layer that prevents slipping and enhances comfort. This top cover can be leather, a synthetic fabric, or microfiber.

        • Outsole (or "Sole"): The very bottom layer of the sandal, the outsole comes in direct contact with the ground. It's responsible for traction, durability, and protecting the foot from rough surfaces. EVA and rubber are two of the most common types of soles.  The sole material significantly impacts the sandal's performance in different environments.

        Before we dive deeper into the specifics of sole materials, it's essential to understand the different parts of a sandal. Each component plays a crucial role in the overall functionality, comfort, and durability of the footwear. Here's a quick breakdown of the main parts of a sandal:

        Understanding these components helps clarify discussions about sandal materials. This is especially important when comparing the benefits and drawbacks of rubber vs. EVA soles. Knowing that the "sole" refers specifically to the outsole allows for a more informed consideration of sole material type.

        Understanding these components helps clarify discussions about sandal materials. This is especially important when comparing the benefits and drawbacks of rubber vs. EVA soles. Knowing that the "sole" refers specifically to the outsole allows for a more informed consideration of sole material type.

         

        Understanding Shoe Sole Materials

        Rubber Soles

        Rubber is a durable and flexible material that is widely used in the soles of shoes and sandals designed for outdoor activities. Recognizable by its heavier feel and distinct smell, rubber soles are often found in hiking sandals and other footwear requiring superior traction and water resistance. You can identify rubber soles by their firm density that will compress very little when pressed.

        EVA (Ethylene-Vinyl Acetate) Soles

        EVA soles are made from a lightweight, foam-like polymer that offers excellent cushioning. Common in running shoes and casual sandals, EVA is known for its soft, plush feel underfoot. To identify EVA soles, look for a smoother, matte finish that compresses easily under pressure.

         

        Comparative Analysis: Rubber vs. EVA Soles

        When deciding between rubber and EVA as a shoe sole material, it's important to compare all the factors to determine which material best suits your needs. From everyday wear to specialized activities, the choice of sole material can impact the sandal's performance, comfort, and lifespan. Let's delve into a detailed comparison, starting with the chart below that highlights key factors and following up with an indepth analysis.

         

        Rubber Soles EVA Soles Durability & Longevity
        Highly durable and abrasion resistant Less durable, compresses and wears down faster. Cushioning & Comfort
        Offers support, less immediate cushioning. More cushioning but at the expense of reliable support. Weight & Flexibility Heavier, offers stability with moderate flexibility. Lightweight, highly flexible. Traction & Slip Resistance Excellent grip on various surfaces, slip-resistant. Adequate traction, less effective on slippery surfaces. Environmental Impact & Sustainability More eco-friendly when natural or recycled rubber is used.  Durability improves sustainability. Less eco-friendly, petroleum-based and does not biodegrade. Recycled EVA is more eco-friendly. Cost Generally more expensive, offers better long-term value. More affordable upfront, but will require more frequent replacement.

        Durability and Longevity

        • Rubber Soles. Rubber stands out for its exceptional durability, making it the go-to choice for footwear designed to endure harsh conditions and heavy use. Rubber's robust composition resists abrasion and wear, allowing it to maintain its shape and functionality over time.

          This makes rubber-soled sandals a wise investment for active, outdoor activities and for people seeking long-lasting options for daily wear. Its robust durability ensures that the sandals remain supportive even with prolonged use.
        • EVA Soles. While EVA offers comfort and flexibility, it doesn't match rubber in terms of longevity. EVA tends to compress and wear down quickly, especially under constant weight or in abrasive conditions.

          This compression can lead to a loss of cushioning and support over time, affecting the overall comfort and effectiveness of the sandals. For light activities or casual use, sandals with EVA soles may work for the short-term, but they will require more frequent replacement than sandals with rubber soles.
        For individuals prioritizing durability and a longer lifespan in their sandals, rubber soles are the superior choice. EVA soles, while comfortable and lightweight, will not provide the same level of long-term durability.  Eva soles are better suited for short-term, casual use.

        For individuals prioritizing durability and a longer lifespan in their sandals, rubber soles are the superior choice. EVA soles, while comfortable and lightweight, will not provide the same level of long-term durability. Eva soles are better suited for short-term, casual use.

        Comfort and Cushioning

        When it comes to the comfort and cushioning provided by sandals, the material of the midsole will play the most pivotal role in defining the wearer's experience.  The outsole is generally a thin layer on the bottom of the midsole so it tends to have less of an affect on a sandal's cushioning, regardless of the material.

        In some cases however, the midsole and the outsole are one single piece.  This is often true for cheaper EVA sandals. In this case the material choice will significantly impact comfort and cushioning.
        • Rubber Soles. Rubber soles provide a firm walking surface. This firmness translates into excellent support and stability. Rubber will not provide the same level of immediate, soft cushioning as EVA. Tread Labs Albion combines a rubber sole with a lightweight PU (polyurethane) midsole.  This gives the sandal the cushioned feel of EVA but with the durability of PU and rubber.
        • EVA Soles. EVA stands out for its exceptional cushioning. The material's foam-like quality creates a soft, plush feel underfoot, making it ideal for maximizing comfort in casual and light activity sandals.  EVA is better suited as a midsole material than an outsole material.

        For those requiring a balance of support, stability, and moderate cushioning, rubber-soled sandals will be the best choice.  


        Weight and Flexibility

        The weight and flexibility of a sandal are largely determined by the material of the midsole, but a thick outsole can still affect a sandal's weight and flex.
        • Rubber Soles. Rubber soles are inherently heavier. This weight can provide a sense of durability and sturdiness. However, excessively thick rubber soles may add extra weight that leads to fatigue faster. Rubber offers reasonable flexibility but it is generally more rigid than EVA. This rigidity supports stability and can help protect your feet from sharp rocks.
        • EVA Soles. EVA is known for its lightweight properties. Sandals with EVA soles are light on the feet, reducing fatigue and making them suitable for leisure activities where minimizing foot strain is desired. EVA's flexibility may make sandals feel comfortable right out of the box, but this same composition makes EVA soles less durable and more prone to cracking and wear.
        If you prioritize a lightweight sandal that offers high flexibility for infrequent light activities, EVA soles may be a good choice. On the other hand, for those requiring a more robust, stable foundation for everyday use, rubber soles provide a better balance of weight, flexibility, and durability.  

        The weight and flexibility of a sandal are largely determined by the material of the midsole, but a thick outsole can still affect a sandal's weight and flex.If you prioritize a lightweight sandal that offers high flexibility for infrequent light activities, EVA soles may be a good choice. On the other hand, for those requiring a more robust, stable foundation for everyday use, rubber soles provide a better balance of weight, flexibility, and durability.


        Traction and Slip Resistance

        The ability of sandals to grip surfaces and prevent slips is crucial, especially in wet or uneven conditions. This is where the sole material plays the most pivotal role.
        • Rubber Soles. Rubber is renowned for its superior traction on a wide variety of surfaces. Rubber soles are ideal for activities near water, such as beach outings, river trekking, or in urban environments prone to rain. Rubber-soled sandals are the go-to option for outdoor activities where reliable footing is critical.

        • EVA Soles. EVA soles provide adequate traction for dry, light activity. They do not offer the same level of grip as rubber, especially on wet or very uneven surfaces. The smoother texture of EVA can compromise its ability to securely grip certain surfaces. EVA soles are more prone to slipping in wet conditions.
        Rubber soles are the superior choice for those needing dependable traction across various activities, especially in wet or uneven conditions. EVA soles are best suited for casual wear and activities in controlled environments.

        The ability of sandals to grip surfaces and prevent slips is crucial, especially in wet or uneven conditions. This is where the sole material plays the most pivotal role.Rubber soles are the superior choice for those needing dependable traction across various activities, especially in wet or uneven conditions. EVA soles are best suited for casual wear and activities in controlled environments.


        Environmental Impact and Sustainability

        • Rubber Soles. Natural rubber, derived from the latex of rubber trees, is one of the most eco-friendly options. Petroleum-based, synthetic rubber has a higher carbon footprint, but this can be offset by incorporating recycled content into the rubber soles.  The durability of rubber soles means less frequent replacements, significantly reducing waste over time and improving sustainability.
        • EVA Soles. EVA is a synthetic material that is not biodegradable, raising concerns about its long-term environmental impact. The production of EVA involves petroleum and chemical processes that contribute to pollution. The shorter lifespan of EVA soles, leading to more frequent replacements, contributes to more waste.

        Cost Comparison

        When it comes to the soles, the material used plays a role in the overall cost of the footwear.
        • Rubber Soles. Sandals with rubber soles tend to be on the higher end of the price spectrum. The cost is attributed to rubber's durability, superior traction, and more complex manufacturing process. While the initial investment may be higher, the longevity of rubber soles means better value over time, as the need for replacements is less frequent.
        • EVA Soles. EVA-soled sandals are typically more affordable due to the lower cost of materials and a simpler manufacturing process. This makes them an attractive option for budget-conscious consumers looking for comfortable and lightweight footwear. EVA's faster wear rate will create a need for more frequent replacements, potentially increasing the long-term cost.
        While EVA soles offer an economical upfront cost, rubber soles provide better long-term value. Consumers should weigh the initial cost against expected lifespan and usage patterns to make the most cost-effective choice.

         

         

        FAQs

        What material is best for the sole of shoes?

        The best material for shoe soles depends on the wearer's needs and the shoe's intended use. For durability, traction, and long-term wear, rubber is often considered the superior choice, especially for outdoor or rugged activities. For lightweight comfort and flexibility, EVA stands out as a viable option, particularly for leisure or light activity footwear.

        Which is a better sole material, rubber or EVA?

        Rubber is generally the better sole material for those seeking durability, superior traction, and longevity in their footwear. It excels in outdoor and challenging environments, offering unmatched wear resistance and safety on various terrain. EVA, while offering excellent cushioning and lightness, does not provide the same level of durability and traction as rubber.

        What is the toughest shoe sole material?

        Rubber is renowned for being the toughest shoe sole material, capable of withstanding harsh conditions, extensive wear, and providing reliable traction across diverse landscapes. Its resilience and material integrity make it the go-to material for footwear designed for durability and rugged use.

        What is a long-lasting shoe sole material?

        For a long-lasting shoe sole material, rubber once again stands out. Its natural durability and resistance to abrasion allow it to maintain performance and structural integrity over years of use. Rubber soles are ideal for anyone looking for footwear that remains reliable and supportive over the long haul, minimizing the need for frequent replacements.  

        Rubber vs. EVA Soles for Sandals: Which One Should I Choose?

        When choosing between sandals with rubber soles or sandals with EVA soles, consider your activities and what you value in footwear. Rubber soles stand out for their unmatched durability and superior traction, making them ideal for both daily wear and outdoor adventures. They offer long-lasting support and robust performance, providing excellent value over time despite a higher initial cost.

        For those prioritizing a balance of performance and environmental sustainability, rubber recycled content is one of the best materials for shoe soles. Rubber soles outperform EVA in challenging conditions and longevity. Opting for rubber-soled sandals means investing in reliability, safety, and durability.

        The best material for shoe soles depends on the wearer's needs and the shoe's intended use. For durability, traction, and long-term wear, rubber is often considered the superior choice, especially for outdoor or rugged activities. For lightweight comfort and flexibility, EVA stands out as a viable option, particularly for leisure or light activity footwear.Rubber is generally the better sole material for those seeking durability, superior traction, and longevity in their footwear. It excels in outdoor and challenging environments, offering unmatched wear resistance and safety on various terrain. EVA, while offering excellent cushioning and lightness, does not provide the same level of durability and traction as rubber.Rubber is renowned for being the toughest shoe sole material, capable of withstanding harsh conditions, extensive wear, and providing reliable traction across diverse landscapes. Its resilience and material integrity make it the go-to material for footwear designed for durability and rugged use.For a long-lasting shoe sole material, rubber once again stands out. Its natural durability and resistance to abrasion allow it to maintain performance and structural integrity over years of use. Rubber soles are ideal for anyone looking for footwear that remains reliable and supportive over the long haul, minimizing the need for frequent replacements.

        When it comes to the soles, the material used plays a role in the overall cost of the footwear.While EVA soles offer an economical upfront cost, rubber soles provide better long-term value. Consumers should weigh the initial cost against expected lifespan and usage patterns to make the most cost-effective choice.

        The environmental impact of sandal soles is an important consideration for eco-conscious consumers.

        When it comes to the comfort and cushioning provided by sandals, the material of the midsole will play the most pivotal role in defining the wearer's experience. The outsole is generally a thin layer on the bottom of the midsole so it tends to have less of an affect on a sandal's cushioning, regardless of the material.In some cases however, the midsole and the outsole are one single piece. This is often true for cheaper EVA sandals. In this case the material choice will significantly impact comfort and cushioning.For those requiring a balance of support, stability, and moderate cushioning, rubber-soled sandals will be the best choice.

         Shop Sandals with Rubber Soles

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