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We’d only just packed away all the tires from our big comparison test when an invitation from Specialized landed in our inbox – asking if we’d be up for visiting the S-Works Tire Factory in Lage. Wait, what? Didn’t the tires in our test come from Vietnam? A quick check of the Specialized models confirms our suspicion: “VIETNAM” is clearly stamped into the black rubber on the sidewall. So how does a Specialized tire production facility in the middle of North Rhine-Westphalia fit into the picture?
At first glance, the answer seems fairly straightforward: whether it’s the DH World Cup or the Tour de France, all of Specialized’s pro teams get their tires straight from Lage. But did Specialized really set up an entire tire production facility just to meet the demands of their sponsored riders? Not quite. As we found out during our visit, this site is far more than just a custom workshop for the pros – but read on to find out for yourself.
The Specialized S-Works Tire Factory in Lage
Tucked away in an unassuming building in an industrial estate in the small town of Lage lies the S-Works Tire Factory. If you’re expecting a flashy facility with a massive Specialized or S-Works logo out front, you’re in for a surprise. The brand from Morgan Hill has taken a far more discreet approach, operating under the name Specialized International GmbH in a modest commercial complex. One thing is immediately obvious: what happens behind these walls is not meant for public view.
Specialized have been operating out of this building for around ten years, although initially on a much smaller scale. Back then, the site was still a long way from becoming a tire production facility. However, from day one, it housed a test lab for finished tires – laying the groundwork for vital research and development. Officially, Google still lists the location as a “design office”, but that label no longer does it justice. About three years ago, the facility began its transformation into a fully fledged R&D hub, one that not only tests completed tires but also conducts extensive research and development on materials.
But that wasn’t the end of the story: about six months ago, the extensive machinery setup was finally completed. Since then, the Lage site has had everything it needs to manufacture tires – marking the birth of the S-Works Tire Factory. With an annual production capacity of just 5,000 to 10,000 tires, the factory in Lage isn’t intended as an additional production site. Instead, it serves as a platform to further refine and innovate the manufacturing process itself. Custom-made tires for the pro teams are more of a welcome side effect.
Every day, a small international team in Lage is hard at work on the “black gold”. Many of the experts originally come from the automotive tire industry – from companies like Continental or Bridgestone, for example.
Why build a factory in Germany?
Tire development is a process of trial and error, where only continuous, incremental adjustments pave the way to success. A dedicated and controlled production facility is essential for this. The problem: major manufacturers have their own production sites, which they can use for experimental purposes.As a relatively small tire manufacturer, Specialized doesn’t have this option. Testing new materials or processes spontaneously in a large-scale factory in Vietnam is difficult.
With the S-Works Tire Factory in Lage, Specialized took control of the process: fast, flexible and equipped with state-of-the-art technology, developers here can experiment freely, independent of mass production. This enables rapid prototyping – Specialized’s tire engineers can immediately incorporate newly received materials into their rubber compounds and directly test and evaluate their effects using actual tires. At the same time, the S-Works Tire Factory makes it possible to create the custom builds mentioned earlier for pro teams – something that would be unimaginable in large-scale production.
Here, the developers have the freedom to create tires with highly specific characteristics: while production tires always have to factor in durability, special race builds can be optimised purely for maximum performance – wear and tear becomes a secondary concern. It’s perfectly acceptable if such a tire is worn out after a single race. So, when Loïc Bruni needs tires tailored to a specific track and set of weather conditions, his rubber is naturally crafted right here in Lage.
To create the perfect tire, what you need above all is extensive chemical expertise and intensive material research. Behind it lies a huge industry – and unsurprisingly, its most important trade shows take place in Germany. So, the choice of location was driven not only by the country’s high standards, but primarily by the close connection to the raw materials and supplier industry. Newly developed materials can make their way into the S-Works Tire Factory as samples without major detours, where they are quickly integrated and evaluated – a crucial step in the quest for the perfect rubber compound.
What actually makes a good rubber compound? The challenges faced at the Specialized S-Works Tire Factory
The perfect tire: maximum traction, balanced damping, top-tier puncture protection – all that with low rolling resistance and minimal weight. Sounds too good to be true, right? Unfortunately, a dream tire like that doesn’t exist. Tire development is – and always will be – a balancing act, where extremely demanding trade-offs must be managed with ever-improving compromises. And the task is no small feat: after all, it’s about finding the best possible balance between grip, damping, puncture resistance, weight, rolling resistance and durability. Which characteristic takes centre stage largely depends on the tire’s intended use. But even DH World Cup athletes benefit when a tire rolls faster. The search for ever-improving compromises is more relevant than ever.
Grip, damping characteristics, rolling resistance and durability are largely determined by the polymer – in other words, what’s commonly referred to as the rubber compound of the tread. And that’s exactly what the team in Lage are deeply focused on. But it’s not simply a case of tweaking rubber hardness to make a tire faster or grippier. Finding the ideal compromise is far more complex. Specialized themselves describe the challenge like this: a good compound needs to be soft enough to conform to the terrain, yet firm enough to deliver reliable grip. At the same time, it must offer a certain level of damping to control elastic rebound – ensuring that the tire maintains consistent contact with the ground.
Grip and rolling resistance are two properties that inherently work against each other. While a compound designed for grip needs to absorb a lot of energy, achieving low rolling resistance requires minimising energy loss as much as possible.
Test it! How the Specialized S-Works Tire Factory puts new rubber compounds to the test
How do you find a compound that strikes the perfect balance between rolling performance and grip? And how can these two factors be assessed even before the production process begins? One answer is the rheometer. It’s a tool used to study the deformation properties of viscoelastic materials. For tires, two situations are particularly important: slow, low-frequency deformations that occur while rolling – which are key to rolling resistance – and fast, high-frequency vibrations or deformations, like those caused by friction over uneven terrain. The latter determines how much grip a compound can deliver.
Because it’s extremely challenging to mechanically replicate realistic loads across a wide frequency range in lab tests, the rheometer employs a clever workaround: it uses temperature control to simulate different mechanical frequency ranges. For all the nerds out there who want more details: this is based on a physical principle called the „time-temperature superposition principle“. Temperature is used as a stand-in for different frequency ranges, providing insight into how a compound behaves under high or low frequency stress. This makes it possible to quickly evaluate a compound’s properties – in terms of both rolling resistance and grip.
In addition to grip and rolling resistance, damping characteristics play a crucial role in how a tire feels on the trail. To assess this characteristic not just subjectively on the trail but also objectively with concrete data, we were introduced to another testing device.This machine, which looks a bit like a sewing machine, is used to measure what’s known as “rebound resilience.” It operates by releasing a hammer, mounted on a pendulum, onto a sample of the rubber compound being tested. The hammer then bounces back, depending on how elastic the material is. The test measures the ratio between the impact energy and the rebound energy, expressed as a percentage. This is determined by the height of the pendulum’s rebound: the higher the hammer swings back after impact, the more elastic the material is – and the more rebound energy it retains.
One key takeaway for us: a tire made with a rubber compound that has a lower Shore A hardness doesn’t automatically offer better damping characteristics! Since damping – or more specifically, the rebound behaviour of the compound – plays a major role in generating grip, a softer rubber compound doesn’t necessarily provide more grip than a harder one either! Specialized demonstrated this with two rubber compound blocks, featuring Shore A hardness ratings of 50 and 54. Despite their similar hardness levels, the rebound resilience test showed very different results. While the compound with a hardness of 50 recorded a rebound resilience of 60%, the other compound with a hardness of 54 converted only 13% of the impact energy into rebound energy!
Softer rubber compound ≠ better damping!
The tensile test is another important method used to assess the durability and structural stability of a rubber compound. After all, a tire is constantly being deformed, stretched, and compressed out on the trail. The tread and side knobs, in particular, must be flexible enough to adapt to the terrain, yet robust and stable under heavy loads to deliver precise handling and long-term durability. No one wants to deal with torn-off knobs!
It’s not just the rubber compound during development that gets tested – the finished tires also have to undergo intensive testing procedures here in Lage. At the S-Works Tire Factory, both endurance testing and rolling resistance measurements are carried out.
A good recipe doesn’t necessarily make a good tire! The manufacturing process inside the Specialized S-Works Tire Factory in detail
People often underestimate just how much craftsmanship goes into making a tire. Even though the S-Works Tire Factory is filled with countless machines, not a single tire rolls off the line without the touch of a human hand. That’s something we were able to witness first-hand in Lage – and even try out for ourselves. Under expert guidance, we had the unique opportunity to build our own tire. And that’s no small task, since the final quality of a tire depends heavily on the manufacturing process.
The production of the tread unit requires a variety of raw materials. A significant portion consists of natural rubber, which inherently offers excellent damping, elasticity, and tear resistance. By blending in synthetic rubber, durability and rolling resistance are further optimised. Around 50% of the compound is made up of rubber.
In addition to natural and synthetic rubber, a tread compound contains a whole range of other ingredients, each playing an important role. Fillers and oils not only improve the compound’s pliability, but also enhance the strength of the polymer itself. Processing aids and anti-aging agents make the material easier to work with and protect the finished product from environmental damage such as UV radiations and ozone – helping to prevent the tire from becoming brittle or cracking prematurely. Finally, curing agents play a key role, too: they crosslink the polymer chains during heating, transforming the sticky raw compound into an elastic, resilient structure.
When exposed to heat, the components are blended into a single compound. The result is a thick, sticky mass at around 150 °C, which is then rolled out and cut to size to match the exact dimensions needed for the tread.
The casing – the tire’s structural underlayer – is made from a pre-processed material that arrives in Lage as a finished unit. It consists of a fabric coated with rubber. This is the only step in the entire production process that takes place externally. Cutting the casing material, however, is done directly on site – and it marks the first opportunity during manufacturing to intentionally influence the performance of the finished tire.
Typically, the casing material is cut so that its threads run at a 45-55° angle relative to the tire’s longitudinal axis – or the centreline of the tread (these are known as bias-ply or diagonal tires). This means that the threads run diagonally to the rolling direction. During the folding process, they cross over each other in multiple layers, which gives the casing its high structural integrity. However, by altering the cutting angle, it’s also possible to produce casing layers with different thread angles – such as 30° or even 70-80°. These angle adjustments allow engineers to fine-tune tire characteristics, for example to improve rolling resistance or enhance ground conformity on rough terrain.
Now the actual construction of the tire begins. First, the cut casing layers are placed step by step onto a rotating building drum and bonded together. Next come the two bead cores made of aramid fibres – these ensure the tire sits securely on the rim later on. In addition, so-called apex inserts made from rubber are added. These enhance the tire’s overall stability and improve puncture protection.
In the next step, the sidewalls are machine-folded inward on both sides. Then the tread is positioned in the centre and pressed on. Fun fact: 50 to 60% of a tire’s total weight comes from the tread alone. This also explains why a tire with a dual-ply casing isn’t twice as heavy as one with a single-ply construction – both use the same tread block, with only the understructure, or carcass, being different.
To prevent air pockets from forming, the tire is rolled with a spiked roller. Once the hot patches have been applied, what’s known as a “green tire” is created. This refers to the finished raw tire that already contains all the functional components – but doesn’t yet have its tread pattern or elastic properties. One final, crucial step is still missing: vulcanisation.
Under pressure and heat, the rubber is cured during vulcanisation, the tread pattern is embossed according to the mould, and the tire gains its final elastic properties. The vulcanisation process itself takes place inside a specific mould that is custom-made for each tire model (tread pattern).
According to Specialized employees, vulcanisation plays a crucial role in the tire’s overall performance – changes in this process have a significant impact on the final product. There are three key variables that can be adjusted during vulcanisation to influence the result:
- Temperature
- Pressure
- Duration
Once again, it’s all about trial and error. It takes countless test runs to determine the perfect “cooking time” for each individual tire.
Conclusions: Specialized S-Works Tire Factory
Nothing is impossible: The S-Works Tire Factory in Lage gives Specialized the freedom to drive an agile, independent development process – completely detached from mass production. Here, new materials and insights can be translated directly into physical prototypes. The focus isn’t just on finding the perfect rubber compound, but also on optimising the manufacturing process itself, which plays an equally crucial role. In the long run, it’s not just factory riders who benefit from this setup, but customers around the world too. We’re excited to see what innovations will roll out next from Specialized’s German-based development centre.
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Words: Lars Engmann Photos: Lars Engmann, Nils Längner
