There aren't many bike brands making their own tyres, let alone racing them on the World Cup mountain bike circuit or in the Tour de France.
Specialized is one such brand – regularly going toe-to-toe with companies that make tyres and nothing else.
What’s more, Specialized riders frequently win using the brand's own tyres.
So, how does Specialized compete with the tyre giants?
The S-Works Tyre Factory, in the small town of Lage, Germany, is the key to answering this question.
It’s Specialized’s tyre innovation centre, delivering small batches of special tyres for special riders – sometimes inside 48 hours.
Behind closed doors
Drive into the quiet industrial estate and you’d be hard pressed to pick out the building that houses the Specialized S-Works Tyre Factory.
There are no flashy signs or tell-tale giveaways – it’s so unassuming, it’s almost covert.
This is Specialized’s first tyre innovation centre. While it’s been here for 10 years, it’s only more recently that the brand has had the ability to produce tyres from start to finish in-house.
While there are only seven people working at the facility, they’re able to produce 5,000 to 10,000 tyres per year.
That may sound like a lot, but a specialist manufacturer such as Maxxis can pump out around 10 times that number… per day.
The idea of setting up such a facility with the ability to turn around small batches of prototype tyres quickly is to create the best-performing tyres possible for the fastest racers in the world, whether they’re on tarmac or dirt.
Let’s not forget that Specialized started out as a tyre business in 1974.
The nuggets of information learned here are then shared with suppliers so production tyres can be improved, including refinements to the production process, rubber compounds and the overall structure of tyres.
The minimalist feel of the office is mirrored downstairs in the high-ceiling production facility.
It’s quiet, impeccably clean, cool and spacious. Did I mention it's clean? While I was expecting noise, fumes, heat and a lot of sweaty workers toiling over clanging machines, it's the complete opposite – clinical and ordered.
Making tyres for the pros
Working in this way, with a focus on one-offs or small batches of prototypes, makes a lot of sense when it comes to giving the racers what they want or need.
As product manager Oliver Kiesel points out, why worry about making Remco Evenepoel a time trial tyre that’ll last 3,000km when 300km will do?
Developing a brand-new tyre is costly and takes time. Some things, Kiesel says, “you have to do, even if there’s no commercial success from it, if it’s super required for racing”.
Take a mud tyre for downhill racing, for example. The chance of Specialized flogging container after container of these is minimal, but if the likes of Loïc Bruni, Finn Iles and Jordan Williams don’t have them, they’re going to be slip-sliding down the hillside and risking a good result in the process.
“Costs are important,” says Kiesel, but they’re “a secondary thing [to performance]”.
A new tyre for the best racers in the world could, after all, influence the next batch of mass-produced treads that come on Specialized’s many off-the-shelf bikes.
Creating a new tyre starts with feedback from the team's riders.
Evenepoel and Bruni will deliver detailed information on how they’ve got on with the current tyres, or what they like about competitors. The engineers then need to decipher this and decide how it translates into what’s needed.
If the team at the S-Works Factory decide there’s a need to create a new tyre, they’ll get busy working on it.
This takes time, though. Designing a tread pattern can take anywhere between four and 12 months. You’re then looking at eight to 12 weeks to cut the steel tooling for the moulds.
Rubber-compound formulation can be quick if it’s just a case of tweaking the process slightly, but if a new ingredient is required, sourcing and testing need to be taken into account, adding to the timeline.
Then, of course, there’s the structure of the tyre. Again, refining this takes testing and time.
The Cannibal tyre – designed for Bruni – was tested with three different heights of Specialized's Apex sidewall protection.
In the end, Bruni opted for one that sat somewhere between the middle and tallest offerings.
Oliver says a prototype can be made in as little as “a couple of days”, which seems incredibly valuable in a world of marginal gains.
Mixologist
When it comes to making the tyres, nearly everything is taken care of within the S-Works Tyre Factory, but it all starts with the compound mixture.
If this isn't right, it almost doesn’t matter what else goes into the tyre or how well it's made.
Neşe Kaynak is the R&D material chemist in charge of mixing up the ingredients that create the rubber compounds.
Finding the right blends of natural and synthetic rubbers, along with everything else that goes into creating the tyre – including oils and fillers, anti-ageing and curing agents – is a never-ending task, but one Neşe seems to relish.
Mixing is done in relatively small five-litre batches, in machines working at high temperatures within a tight operating window, to ensure they’re able to create the correct reaction.
This produces around 10 mountain bike tyres, or 20 to 30 road tyres.
Compare that to a mass-production mixer, which will work with 200kg of material, and you can see the difference in scale.
The big lump of sticky black goo is cooled, rolled flat then extruded into a workable strip of rubber ready to be turned into the tread of the tyre.
But, as you’d expect here, it’s done as precisely as possible, using a custom machine that has been scaled down for the job.
This extrusion machine is fitted with more sensors and lasers than a James Bond villain’s lair, helping to keep tolerances tight (we’re talking +/- 0.3mm for the thickness and +/- 0.2mm for the width) for a better-finished product.
This determines the thickness and dimensions of the rubber, ensuring there are adequate amounts in the right places to form the correct tread heights during the curing process.
Black magic
During the prototype phase of tyre construction, the compounds are tested rigorously to ensure they deliver for their intended use.
The lab inside the S-Works Tyre Factory is extremely sophisticated. But delivering accurate information on how a tyre will behave on the road or trail from this room isn’t easy.
To get a handle on the rubber characteristics, Specialized employs a rheometer – a device for studying the properties of viscoelastic materials.
This clever bit of kit uses different temperatures to simulate mechanical frequency ranges. Performance during high-frequency vibrations (think fast deformations of the rubber while the tyre tries to create friction through a turn or under braking) will help illustrate the grip on offer, while low-frequency vibrations give some idea as to how the tyre will perform while rolling.
The damping properties of the compound are also key here, too. Here, the team measures rebound resilience, using a machine that looks a little like a Charpy test rig (used for impact testing), though a little more advanced.
This rig releases a hammer onto the sample disc of rubber, providing a read-out to illustrate how much energy the material can absorb. The lower the hammer returns after impact, the less elastic the rubber compound is.
While I'd always assumed that the softer the rubber compound, the more grip would be on offer, that isn’t always the case. According to Neşe, it’s more about the rebound properties and how it deals with the impact energy.
A lower rebound resilience should mean the material is better at damping vibrations and absorbing impacts.
Then, of course, they need to assess durability and the structural integrity of the rubber compound.
It’s all good and well having the grippiest tyre going, but if you’re selling a tyre that sheds shoulder treads every time you rip around a turn, customers aren’t going to be over the moon.
As ever, striking the right balance with the compound mix is key, and takes a lot of trial and error inside and outside the lab.
Ply me a river
Once they’re happy the rubber compound is exactly what they’re after, the team can start laying up the rest of the tyre.
Here’s where the only bit of material is used that isn’t produced inside the factory.
Specialized orders in pre-produced fabric to create the tyre casings.
On what looks like a massive conveyor belt, engineers are able to lay out and cut the casing fabric (or casing plies), angling the threads deliberately (the angle measured relative to the centre of the tyre), depending on the end use.
Different tyres may require multiple layers of fabric (downhill tyres will typically use a two-ply construction) and different casing or thread angles.
Around 50 degrees is typical for most gravity-style tyres, although upping this to in the region of 70 degrees could provide more grip by increasing how easily the tyre can deform. Doing this compromises other factors, though, so finding a balance is key.
Building blocks
With all the component parts ready, the tyre assembly can begin.
Using a machine imaginatively named the ‘tyre building machine’, the technicians are able to start constructing the tyres.
Each element of the tyre is fitted to different spools within the machine. These then feed the tyre casing, sidewall reinforcement, bead material and rubber compound onto the rotating tyre-building drum, in a specified order. This sequence is pre-programmed into the machine to limit mistakes.
The technician carefully lays each section down onto the drum, building from the inside-out and with laser-guided precision to ensure every component is aligned correctly.
Before the thick strip of extruded rubber (soon to be the tread) is applied, the tyre-building machine folds the sidewalls.
Hot patches denoting the model, casing and compounds can then be applied.
At this stage, the ‘raw’ tyre can be removed from the drum. It’s still lacking shape and definition, though.
Feeling the pressure
Now, the raw tyre is placed inside a machined mould. This mould will vary from tyre to tyre, depending upon the tread pattern.
Heat and pressure are then applied to the tyre. This not only gives the tyre its recognisable shape, it also vulcanises the rubber.
This helps it become more durable, stronger and more elastic, and hopefully ensures the tyre is able to do what’s expected of it on the trail or road.
As with pretty much everything else in the factory, Specialized has put its own mark on the machinery used to cure the tyres, adapting mass-production technology and making it work better for its needs.
Using electric heating rather than steam, Specialized is able to adjust the process more easily, tweaking when necessary in order to optimise performance.
Likewise, altering the pressure and curing time can play a part in the end result.
A Cannibal tyre, for example, will take about eight minutes to cure. That number hasn’t been plucked out of the air. It’s down to experimentation, trial and error.
The team here think they can produce around 20 downhill tyres a day.
Once the tyre is cooled, the team can set about carrying out rolling resistance and destruction tests until they’re happy they’ve created the ultimate tyre for the task at hand.
Only then will the tyre be boxed up and shipped off to the teams, where it’s down to them to do the winning.
While it could be easy for Specialized to simply buy tyres from an established vendor, it’s impressive that it has chosen this far more complex and costly route.
It’s testament to the brand's love of racing and its will to win that this place exists.
And while the focus here may be on creating the fastest tyres possible for the pros, there are knock-on benefits for the consumer, which can only be a good thing.
