Sandal Anatomy: What Are Earth Runners Made Of?

Simple by design doesn't mean simple in construction. Earth Runners combine time-tested huarache principles with modern materials and thoughtful engineering to create sandals that are lightweight, secure, responsive, and built for adventure. Discover the purpose behind each component and see how every detail works together to support natural movement and all-day comfort.

Our Laces

The lace system is one of the most important features of any minimalist sandal. It determines how securely the sandal stays on your foot, how comfortably it moves with you, and how it performs over time. Earth Runners offers several lace options, each designed with a specific balance of comfort, durability, and adventure-ready performance in mind.

Lifestyle Laces: Comfort

We now offer two different types of Lifestyle Lace featuring different constructions:

1. Classic Lifestyle Laces = double-ply construction + double stainless steel stitch
   
   Featuring the same two-component design of our Performance Laces, yet the abrasion-resistant nylon trim reinforcement is much thinner which makes the lace more pliant. Lifestyle Laces feature a 5/8" or 1/2" wide nylon and lined with a thin strip of Mil-Spec nylon on the top side. Softer and reinforced, Classic Lifestyle-Laced Sandals are the best choice for daily comfort with those of medium to large feet.
   
   
2. Ergonomic Lifestyle Laces = double tubular webbing + single stainless steel stitch
   
   Our most pliant and comfortable laces yet! Featuring a single component double tubular webbing with a weave design geometry that easily burrito folds at the toe post allowing it to ergonomically conform comfortably to the contours of your toes. The 9/16" wide nylon lace features a conductive stainless steel stitch down the center. Softer and most pliable, Ergonomic Lifestyle-Laced Sandals are the best choice for max comfort for people with smaller feet.
   

Performance Laces: Security

In a quest to create the ultimate water performance lace we worked with a specialty mill manufacturer to create laces with the greatest longevity, function, and comfort on both land and water. Performance Laces feature a 1/2" soft hydrophobic polyester webbing that is wrapped in a highly abrasion resistant Mil-Spec nylon, resulting a in 9/16" wide lace. The outer sheath wraps all the way around the core webbing while leaving a gap down the top center third allowing the toe post to fold tightly between the toes for maximum comfort and performance. 

How to Choose the Right Lace System

Performance Laces offer more security and longevity while Lifestyle Laces offer more comfort.

For small feet, Lifestyle laces will be the most comfortable. Ergonomic being softest, and Classic providing a bit more structure and security. For large feet, we suggest Classic Lifestyle laces for comfort, or Performance laces for security.

The additional tensile strength of our performance laces become more and more noticeable on bigger sandals, with longer laces, as there is a greater load to secure with a larger user.

Grounded Conductive Laces™

Our earthing sandals are designed to keep you grounded to bare Earth via our Grounded Conductive Laces™. Nature is the ideal place for this, as natural surfaces connect you to the native circadian rhythm and Schumann Resonance of the Earth.

Earth Runners worn on bare Earth allow the copper lace plug situated on the outsole to make effective connection with the ground, facilitating electron transfer between your body and the Earth through the stainless steel lined lace circuit. This effectively grounds the body via the intimate connection of lace and foot–similar to that of being barefoot. You can view a video on our YouTube here of a voltmeter test showing the conductivity of our sandals.

Adventure-Ready Ergonomic Lacing System:

The historical use of our lacing system–using a single lace to bind the feet to a sandal–has been in existence for thousands of years; the most well-known example being the huarache running sandal of Northern Mexico. The persistence of this tried and true design speaks volumes to its efficiency and effectiveness.

Through 6 years of rigorous research and development for creating the ultimate adventure-friendly running sandal for both land and water, we have found the ancient huarache design to be the most simple, comfortable, secure and free. The ergonomic routing of our laces harnesses the least dynamic areas of the foot to avoid friction and maximize freedom. Our triangular hugging anchor points on the sides of the sandal maximize the security of the heel. This helps to minimize lateral and longitudinal heel motion, which is critical to keep you adventure-ready and stable across varied terrain!

No™ Toe Box

Toe and metatarsal freedom assists with proper distribution of body weight and optimal ankle and knee stability, as well as allowing the toes to more aptly sense and react to the environment via less proprioceptive interference. Earth Runners feature a single thong strap over the least dynamic portion of the forefoot with a wide sandal platform and no toe box for full toe mobility. No™ Toe Box allows the toes to extend to the sky unencumbered with every stride and splay naturally upon landing.

By renouncing the standard cramped and unnaturally-shaped toe box, Earth Runners sandals allow for maximum comfort and movement efficiency.

• Foot-freedom, no toe box to conform to.
• Free toes: toes can extend, lay and splay naturally.
• More powerful toe-off with every stride.
• Supports your body's natural shock absorption system.
• Feet are able to stabilize pronation (inward tilt) naturally.
• No Toe Box allowing the foot to breathe and sense temperature.

Zero Drop:

Zero-drop soles are the same thickness from the toes to the heel–the natural position of our feet. Many running shoes have elevated heels which promote heel striking and increase stress on your bones and joints. Soles that are zero-drop maximize proprioception and encourage proper gait, which minimizes landing impact. Zero drop shoes don't alter the angle of the foot in relation to the body and ground, (the same as being barefoot) therefore not adversely affecting the geometry and length of the Achilles tendon--the thickest tendon in the human body.

Responsive Minimalist Soles: 

Responsive soles avoid the clumsy effect overly cushy soles have on bio-mechanics by offering a responsive interface between the body and ground with minimal yet effective protection. Stable responsive soles provide accurate biofeedback from the terrain underfoot, resulting in a more precise and accurate gait cycle. We aim to avoid proprioceptive confusion caused by feet pushing through thick cushioned soles in search of a stable and predictable platform to react to (the ground). This effort to achieve feedback from the terrain through unresponsive soles results in a loss of energy and bio-mechanical fluidity. We opt to offer minimalist sandals with responsive soles to help promote proprioceptive skills, proper biomechanics, and healthy running form in pursuit of the ultimate barefoot experience.

Earth Grip Footbed

In extreme endurance events sandals are sure to get drenched in sweat and are likely to become submerged in water. When the Earth Grip Footbed gets wet, the composition is able to pull moisture away from the foot and into the cotton canvas membrane, helping to preserve traction. By preventing moisture accumulation and pooling under the foot, the (mild bare earth equivalent) textured cotton canvas maintains traction in both wet and dry conditions. Two thumbs up for the sweat-wicking and amphibious traction on this footbed!

Our Earth Grip footbed is dyed in small batches using GOTS certified organic dye in Los Angeles, California. The fabric itself is not certified organic. The farmers in India who grow our cotton use traditional practices that have been in place for over 100 years - before modern fertilizers were introduced. We laminate the Earth Grip footbed to the Vibram® outsole using solvent-free adhesive.

Sandal Care & Maintenance

Sandal smells can be best maintained with a regular cleaning in the shower to avoid accumulation of sediment, bacteria, and odor. We recommend taking your sandals into the shower once a week for a scrub and rinse, see sandal cleaning tools here. 

Our hose sandal cleaning nozzle attachment offers a deeper clean, which we recommend using once a month to achieve a full cleansing of the footbed material. To keep odor under control: Brush 1x/week & Nozzle 1x/month.

Baking soda is a known odor-eliminator. Sprinkle your sandals with a nice coating of baking soda, gently rub into the footbed, and let sit overnight.

If combatting a more persistent odor, sun dry (for no longer than 30 minutes) after cleaning, and then spray them with a strong antibacterial essential oil & water blend (lavender or tea tree).

We recommend staying one step ahead of the smell with regular footbed cleaning to prevent the inevitable build-up of dirt & sweat.

Locking Buckle:

The lace routing on our huarache running sandal-inspired design is unique and is made possible by our proprietary locking buckle. We custom designed this hardware with our friends at Twin Performance Engineering to surpass the high performance demands put on our Earthing Adventure Sandals. With their in-house 3D printer we were able to prototype over ten iterations of the buckle until we had the perfect design that proved itself during rigorous testing out in the wild. This low-profile buckle is designed to be (1) extremely durable and (2) hold high lace tension with zero slip or un-buckling while in action. Our buckles are injection molded in Santa Cruz, California with 25% recycled plastic.

Our Soles

Every Earth Runners sole is selected to balance natural movement, grip, durability, and comfort. Rather than using a one-size-fits-all approach, we pair each sandal with the compound that best matches its intended use. Softer compounds provide a more cushioned ride, while firmer compounds generally offer greater resistance to abrasion. No matter which sole you choose, the terrain you spend the most time on will have the greatest impact on how quickly your sandals wear.

Natural surfaces aren't just better for grounding—they're also easier on your sandals. The same trails, forests, and earth that provide the richest sensory experience also tend to be the least abrasive, helping extend the life of your soles.

Durability by Terrain

While all Earth Runners are built to withstand years of adventure, the terrain you spend the most time on has a significant impact on how quickly your soles wear. Rough, abrasive surfaces naturally wear footwear faster than softer, more forgiving ground.

Frequent use on pavement and coarse rock will shorten the lifespan of any minimalist sandal due to the constant friction between the sole and the ground. Softer natural surfaces like soil, pine needles, and grass are much gentler on the rubber and typically result in significantly longer sole life.

Different sole compounds also offer different balances of cushioning, weight, grip, and longevity.

Vibram® Gumlite Compound

An expanded rubber compound weighing approximately 40% less than solid rubber, Vibram® Gumlite is engineered for an excellent balance of lightweight comfort and long-lasting durability. It provides dependable traction across varied terrain and maintains reliable grip even in cooler temperatures.

Best for: Daily wear, hiking, mixed terrain, and users looking for a balance of cushioning and longevity.

Used on: Circadian Sandals

Walkbase GumEVA Compound

 

Walkbase GumEVA is an expanded rubber compound that is approximately 30% lighter than solid rubber and contains 40% natural rubber with no petroleum. It offers excellent durability with confident traction, including on wet surfaces, while maintaining a comfortable ride.

Best for: Everyday adventures, wet environments, and all-around versatility.

Used on: Primal Sandals

Vibram® Morflex Compound

 

Morflex is an ultra-light microcellular blend of EVA and natural rubber that weighs roughly half as much as solid rubber. Its softer composition delivers the most cushioned and forgiving ride in the Earth Runners lineup while maintaining reliable traction across a wide variety of terrain.

Because comfort and cushioning come from a slightly softer compound, Morflex will generally abrade faster than firmer rubbers when used extensively on highly abrasive surfaces such as asphalt or coarse rock. Many customers happily trade a small amount of longevity for its exceptional underfoot comfort.

Best for: Road walking, travel, casual everyday wear, and those prioritizing lightweight comfort.
Used on: Atlas and Alpha sandals

FAQ

What is the difference between Performance Laces and Lifestyle Laces

• Performance laces: Security > Comfort - Webbing wrapped 300° in mil spec grosgrain reinforcement.
• Lifestyle laces: Comfort > Security - Webbing wrapped 120° in mil spec grosgrain reinforcement.

What makes Grounded Conductive Laces™ different from regular laces?
Our stainless steel (SS) & copper plug grounds our laces via the 100% SS thread on the bottom.

What is a zero-drop sole and why is it important?
The entire foot (heel and toe box) is in the same plane with zero difference in height from the heel to the forefoot.

What is the Earth Grip footbed and how does it work?
Our Earth Grip footbed is a thick weight canvas that wicks moisture from the foot and offers traction in water by preventing the foot from hydroplaning when wet.

What sole compounds does Earth Runners use (Vibram, Walkbase, etc.)?

Vibram:

• Morflex: Expanded rubber that weights 50% less than solid rubber
• Gumlite: Expanded rubber that weights 40% less than solid rubber
• Megagrip: solid butyl rubber for ultimate traction all wet/dry terrain

Walkbase

• GumEVA: Expanded rubber that weights 30% less than solid rubber

How does the locking buckle system work on Earth Runners sandals?
The locking cam buckle results in zero slip from the lace fastener. Once you find you preferred lace tension setting you can than than slip you sandals on and off with no further adjustment needed.

How do Earth Runners achieve grounding/earthing through their sandals? 
Our stainless steel ground plug and 100% SS threaded lace circuit grounds the foot and body when on natural ground surfaces.

What materials are best for minimalist sandal laces and why?

Synthetic:

• Nylon: High abrasion, medium water stability - loosens
• Polyester: Medium abrasion, high water stability

Natural:

• Cotton/Hemp: Low abrasion, medium water stability - tightens
• Leather: Medium/low abrasion, low water stability - loosens

How durable are the different sole compounds on Earth Runners sandals?
The durability of the sole is largely correlated with its density and weight.

Weight / Durability / Grip:

• Rubber (Solid): High
• Expanded Rubber (60-70% solid) : Medium
• EVA (40-50% Solid): Low

How does sandal anatomy affect foot health and natural movement?
Our flat sole and no toe box secure lacing system allows the toes to extend and the forefoot to splay allowing for a natural unencumbered gait cycle with ample proprioceptive feedback. 

Last Updated: July 21, 2026