July 31, 2026
With the arrival of high temperatures, urban tarmac can easily reach temperatures in excess of 50 °C or 60 °C. For the footwear industry and for the end user, this scenario poses a key challenge: how does the sole respond to extreme heat?
The thermal behaviour of footwear affects not only foot comfort but also the structural durability of the shoe, grip on the pavement and resistance to abrasion.
In this article, we analyse how five of the most widely used materials in sole manufacturing (recycled rubber, EVA foam, polyurethane, leather and TR) react, and when it is advisable to choose each one depending on the intended use.
Key factors: What do we look for in a sole in summer?
To assess a sole’s heat resistance, we need to consider three main technical variables:
1. Softening and deformation point: The material’s ability to retain its shape and density without losing its mechanical properties at high temperatures.
2. Thermal insulation: The barrier provided by the sole to prevent heat accumulated on the ground from being transferred into the shoe.
3. Grip and traction: Maintaining grip on dry, hot or polished surfaces.
Comparison table of summer sole materials
Below, we summarise the characteristics of each material to provide an overview of their performance during the summer months:
Comparison table of summer sole materials.
Below, we summarise the characteristics of each material to provide an overview of their performance during the summer months:
In-depth analysis: When is each material best suited?
Each material has a specific purpose and a context in which it performs at its best. Understanding these differences enables brands and designers to make the best decisions for their summer collections.
1. Recycled rubber: Maximum strength and grip in the sun
Rubber sourced from recycled tyres has a unique structural advantage: it was originally designed to withstand the friction and extreme temperatures of the road.
·When it’s the best choice: It’s ideal for heavy-duty footwear, urban styles, boots, outdoor footwear or sustainable fashion designs seeking maximum durability.
·Summer benefits: It doesn’t soften or lose density on hot tarmac. It offers exceptional technical grip and acts as a durable thermal shield, whilst also providing distinctive environmental benefits.
2. EVA foam: Ultimate lightness and thermal comfort
EVA (Ethylene Vinyl Acetate) is internationally recognised for its ultra-lightweight density and shock-absorbing properties.
·When it’s the best choice: It’s the go-to material for casual summer footwear, beach shoes, flip-flops and lightweight trainers.
·Summer benefits: Its foamy structure, filled with micro-air bubbles, makes it a highly effective natural thermal insulator. It is the ideal choice when minimal weight is the priority.
3. Polyurethane (PU): A balance between comfort and durability
Polyurethane combines great flexibility with a remarkable ability to absorb impact without adding excessive weight.
·When it’s the best choice: It excels in comfort sandals, ergonomic footwear for long walks, and professional or work footwear in summer.
·Summer strengths: It maintains consistent flexibility and offers a cushioned feel underfoot all day long, whilst being remarkably resistant to wear and tear from everyday use.
4. Natural leather: Breathability and timeless elegance
Leather is the traditional material par excellence. Its organic origin gives it unique thermoregulatory properties.
·When it’s the best choice: Essential for dress shoes, loafers and high-end formal shoes for summer.
·Summer benefits: It allows the foot to breathe naturally and does not trap moisture inside. Furthermore, it withstands heat perfectly without altering its molecular structure or melting.
5. TR (Thermoplastic Rubber): Versatility and design flexibility
TR allows for precise moulding with a wide variety of finishes, making it a staple in ready-to-wear footwear and casual fashion.
·When it’s the best choice: Excellent for casual urban fashion collections, youth footwear and seasonal trends.
·Summer strengths: It offers a well-balanced combination of flexibility, clean aesthetics and ease of manufacture, making it ideal for moderate summer temperatures.
Conclusion: Choosing the right sole for the purpose of the footwear
There is no ‘one-size-fits-all’ sole for summer; rather, there is a suitable sole for every need:
If you’re looking for lightness and cushioning for the beach or for relaxing, EVA foam is the natural choice.
If you prioritise elegance, refinement and breathability, leather remains the king of style.
If you need ergonomic support for walking for hours on end, polyurethane provides the necessary support.
If you’re looking for flexibility and a variety of designs, TR delivers with agility.
And if your priority is extreme durability, unbeatable grip on scorching tarmac and environmental commitment, Tiresoul’s recycled rubber is the solution offering the highest technical performance and a sustainable track record.
Are you a footwear designer or manufacturer?
Discover how our recycled rubber treads bring durability, traction and character to your summer collections.
