FKM RUBBER STRAPS VS SILICONE STRAPS

For those that have done even the slightest of research for alternative strap options for your luxury watch, you will no doubt come across rubber straps. Other than the colour, at first it seems like that is the only difference between brands. However, there are two main types of rubber watch straps you can buy, and one of them tends to be the much better choice. To help you better understand the difference between the two, today, we are going to go into what makes an FKM or Silicone strap the way they are.

Four ZEALANDE rubber straps in navy blue, white, red and black with brushed steel buckles.

We will start by taking a look at the FKM rubber strap as that is what ZEALANDE exclusively uses for their rubber straps. KM rubber watch straps have become a favourite among us watch enthusiasts who want the perfect balance of durability, comfort, and refined aesthetics. FKM, which stands for fluoroelastomer, is a high-performance synthetic rubber engineered to withstand extreme environments. Unlike traditional silicone or natural rubber straps, FKM straps are designed to resist chemicals, UV radiation, temperature fluctuations, and everyday wear, making them ideal for divers, athletes, and anyone who wants a long-lasting premium band.

FKM rubber is created through a specialized chemical process that results in an exceptionally dense and stable elastomer. Production begins with a base fluoroelastomer polymer, which is blended with curing agents, pigments, and stabilizers. This mixture is then thoroughly milled to ensure uniform distribution of all components, giving the final product consistent strength and flexibility. Once the blend is prepared, it is placed into precision molds that shape the strap’s form, texture, and integrated features. The molded straps are cured through high heat and pressure, known as vulcanization, which crosslinks the polymer chains, locking in the strap’s elasticity, structural integrity, and chemical resistance. This process ensures that all of ZEALANDE’s straps are sure to hold up over time no matter who much you wear them.

After curing, the straps undergo several finishing steps that elevate both function and appearance. Rough edges are trimmed, surfaces are polished or matte-finished, and any perforations or grooves for ventilation are refined. Some FKM straps, like the Rolex Oysterflex bracelet, may also be reinforced with stainless-steel or titanium hardware, molded keepers, and quick-release spring bars for easy installation. Additional treatments, such as surface texturing or embossed patterns, improve grip and comfort while giving each strap a distinctive style.

The result of this meticulous manufacturing process is a strap that feels smooth and supple on the wrist while offering exceptional longevity. FKM rubber retains its flexibility over time, resists deformation, and remains comfortable even in hot, humid, or aquatic environments. Its colourfast nature ensures that vibrant or deep colours stay rich without fading. For watch lovers who appreciate reliability paired with modern style, FKM rubber straps are really the only way to go. But now let's have a look at the alternative option.

Rubber Strap for OMEGA® Seamaster Diver 300M Co-Axial 42mm Blue Ceramic "Tokyo"

Silicone rubber watch straps are known for their soft, flexible feel, vibrant colour options and cheaper price point making them a popular choice for many people. Made from a synthetic polymer known as polysiloxane, silicone rubber offers excellent flexibility, water resistance, and biocompatibility, qualities that make it comfortable on the skin and suitable for prolonged use. Its ability to maintain pliability across a wide temperature range also makes it ideal for sports watches, fitness trackers, and casual timepieces

The manufacturing process of a silicone rubber strap begins with the formulation of the silicone compound itself. Liquid or solid silicone is blended with curing agents, pigments, and reinforcing fillers to achieve the desired colour, durability, and elasticity. This mixture is thoroughly kneaded through a process called “compounding”, ensuring the ingredients are evenly dispersed and producing a material that will cure uniformly. Once prepared, the silicone compound is shaped using compression molding, injection molding, or liquid silicone injection, methods that force the material into detailed molds designed to form the strap’s contours, textures, and integrated features.

Bright blue silicone watch strap with a polished steel buckle on a wooden surface.

During molding, the silicone is exposed to heat and pressure, initiating vulcanization like with FKM straps, the chemical process that crosslinks the polymer chains. This step transforms the material from a soft, uncured mass into a resilient, flexible strap that holds its shape. After curing, the strap is removed from the mold and undergoes finishing processes such as trimming excess material, smoothing surfaces, and punching holes for buckles or ventilation. Some silicone straps are given a matte or satin finish to enhance comfort, while others incorporate molded patterns to improve breathability and grip.

Hardware components, such as stainless-steel buckles or quick-release spring bars, are installed in the final assembly stage to ensure proper function and compatibility with a wide range of watches. Many manufacturers also treat silicone straps with surface coatings or dust-repellent finishes to reduce the tacky feel that silicone can sometimes exhibit. The finished silicone rubber strap is lightweight, hypoallergenic, and exceptionally comfortable, making it ideal for daily activities, workouts, and outdoor adventures. Its vibrant colours, smooth surface, and easy-to-clean nature make silicone an attractive choice for wearers who prioritize comfort and versatility.

Now we have seen what makes FKM and silicone straps their unique selves, let's start by having a look at the differences between the two.

FKM and silicone rubber watch straps are pretty much the only rubber strap options for timepieces, each offering distinct advantages that appeal to different types of wearers. While both materials fall under the broader category of synthetic elastomers, they differ in performance, durability, and overall feel. Understanding these differences can help you choose the strap that best suits their lifestyle, environment, and aesthetic preferences.

Silicone rubber straps are known for their soft, smooth texture and exceptional flexibility. They are lightweight, comfortable for everyday wear, and excel in situations where comfort is the primary priority. Silicone remains pliable across a wide temperature range and is hypoallergenic, making it suitable for sensitive skin. However, silicone tends to attract dust and lint, and its durability under harsh chemical exposure or prolonged UV radiation is comparatively lower. Over time, frequent bending or exposure to oils and solvents can cause silicone to degrade faster than more robust elastomers. This means if you want to buy the cheaper silicone strap you will likely need to re-buy the same strap a few months later depending on how much you wear it. This is because they are not as durable and the colour can fade along with the surface changing from its matte original finish to a shiny surface as you wear it.

Black perforated silicone watch strap with a steel tang buckle on a wooden table.

FKM rubber straps, on the other hand, are engineered for high performance in demanding environments. FKM offers superior resistance to chemicals, oils, fuels, UV light, and extreme temperatures. This makes FKM the preferred choice for divers, outdoor enthusiasts, and individuals who need a strap that can withstand tough conditions without losing its integrity. FKM straps are denser and more rigid than silicone, but they soften comfortably with wear while maintaining long-term structural stability. They are also less prone to dust attraction and colour fading, giving them a more premium, durable feel. ZEALANDE understands that you do not want your strap to break or fade colour over time so that’s why they use FKM rubber exclusively.

Rubber Strap for Tudor® BLACK BAY FIFTY-EIGHT Black Rubber Straps ZEALANDE

When comparing longevity, FKM clearly outperforms silicone. Its dense molecular structure and high heat resistance allow it to retain its shape and elasticity even under heavy use. Silicone remains more affordable and highly comfortable, but it is more susceptible to tearing, stretching, and surface wear. In terms of aesthetics, both materials offer a wide range of colours and textures, though FKM generally provides deeper, richer colour saturation and a more refined finish due to its more robust construction.

Ultimately, the choice between FKM and silicone rubber watch straps comes down to use case and personal preference. Those seeking maximum comfort and a lightweight feel may gravitate toward silicone, especially for casual or fitness-focused wear. Meanwhile, users who prioritize durability, resistance to harsh conditions, and a premium tactile experience will likely find FKM to be the superior option. Both materials serve distinct purposes well, and choosing the right one ensures a balance between comfort, performance, and longevity.

However, to prove that ZEALANDE’s choice of using FKM rubber is the best option, we will have a quick look at what other watch brands use as their rubber strap options for their materials.

In the world of luxury watches, Omega is an excellent example of a brand that uses high-quality rubber straps on some of its sport models. While Omega’s own OEM straps vary by model, many Seamaster and Speedmaster variations are offered with durable FKM rubber options that meet the performance demands of diving and daily use. Omega also opts for just using KFM as not only does it feel more premium than silicone, it is far more durable.

Omega Seamaster Diver 300M with black dial on a black rubber strap, worn on the wrist.

Rubber Strap for ROLEX® Submariner Without Date (6 Digits until August 2020) Rubber Straps with tang buckle ZEALANDE

Rolex has its own unique approach to rubber-like straps, the brand’s proprietary Oysterflex “bracelet” is a hybrid FKM rubber strap with a titanium and nickel core that behaves more like a bracelet than a traditional strap. Although Rolex doesn’t describe its Oysterflex as FKM by name, it uses KFM rubber around the titanium plate. However, Rolex only offer their Oysterflex bracelet on their precious metal watches so make sure you check out ZEALANDE’s bracelets if you are looking to change up the look of your Submariner, GMT or Daytona! For Tudor, a sister brand to Rolex, rubber straps are also a key part of the sporty aesthetic of many models such as the Black Bay and Pelagos lines. These straps are made from durable FKM rubber suited for diving and daily wear.

Finally, Patek Philippe, traditionally known for its dressier timepieces, has embraced FKM rubber straps in sportier collections like the Aquanaut and Nautilus. These models often come with. While Patek’s own straps are usually developed to exacting standards for their watches, aftermarket FKM straps are available from specialist makers to suit these luxury sport watches. Like, ZEALANDE that makes a straight end rubber strap that could easily be used on your Aquanaut.

And there you have it, a comparison between FKM and silicone rubber straps and hopefully now you know why here at ZEALANDE only FKM rubber is used. You do not have to look far to other watch brands either to see why they choose FKM as well, its durability is what makes it the best material to use. Not to mention, your luxury watch deserves to have the same quality put into its rubber strap, that is why ZEALANDE can guarantee that your wearing experience with their bracelet will be incredible.