“We use natural rubber in racing tyres because it has a higher stretch ratio, so it’s more resistant to tearing,” says Dunlop race tyre engineer Stefan Nasello. “Silica has benefits in road tyres but in racing we need the strongest material because teams have a habit of pushing things over the limit.”
Nasello works at Dunlop’s main racing tyre production facility, which is located at the tyre firm’s factory in Hanau, Germany, a site that recently celebrated its 125th year of work. These days the factory specialises in high-performance tyre production, making boots for only the fastest of supercars, such as the Porsche 911 GT3 RS, and for Dunlop’s racing activities, which has included supplying the whole BTCC grid with its tyres since 2003.
“We also supply tyres to teams in the LMP2 and GTE classes of the World Endurance Championship, as well as teams in the VLN endurance series in Germany,” says Nasello. “In these cases there’s tight competition against other tyre brands, so we’re always working flat out.”
That’s what makes the tyre production process employed by the 37 operators at the Hanau racing tyre facility so crucial. One tiny mistake in the manufacturing process, one millimetre’s worth of misaligned material, and the results might not reveal themselves until a racing car suffers a mid-race blowout two weeks later. That’s not something Dunlop, or any racing tyre manufacturer for that matter, wants to endure.
“Racing tyres are actually made of fewer parts but they have to deal with much, much higher loads, so our operators are highly trained,” explains Nasello as he shows us around the factory “It’s a very detailed job, yet we produce around 150 tyres per day, all by hand.”
There are 18 parts in each racing tyre compared with 22 for a road tyre, because each component is focused on one job: to provide grip. Road tyres, on the other hand, have to work in a much wider variety of conditions, while acting as a component of the car’s suspension and, increasingly in recent times, offering low rolling resistance.
Yet it’s the work of a racing tyre maker – not a road tyre-making machine – that is most impressive. Watching one in action is a bit like observing a bespoke tailor demonstrate their craft. They stand in front of their workstation and slice and fold rubber with the same conviction as a Savile Row sewist. Each can roll sheets of this material, which has been supplied to Dunlop from contracted rubber tree farmers located in Thailand, Malaysia and Indonesia, at such pace that it takes just 15 minutes to create a racing tyre’s internal carcass. This rubber carcass is not visible once fitted to a wheel, but is key to its performance because it ensures the tyre can sustain substantial loads, such as surviving a 20-minute race around an abrasive circuit such as Thruxton at an average lap speed of 115mph.