Photo: Bentley
Bentley's Mulliner division has revealed the largest carbon fiber wheel in production, the 22-inch Mulliner carbon wheel. It is designed for the Bentayga, and it took five years of engineering to enable it to pass German TUV testing, making it the first of its kind to receive this approval.
Mulliner worked with leading composite manufacturer Bucci Composites to develop this type of wheel and its manufacturing process. The new 22-inch rims from Bentley are made with Resin Transfer Molding (RTM) technology.
The innovative technology promises repeatable quality and involves cutting carbon fiber cloth into predetermined shapes. Specialists then stack the weave segments in a specific manner, heat them with a special machine, and then drape them into the mold. Once that step is completed, the three-dimensional preforms get arranged into an even larger mold, where they get injected with resin and hardener, and are then placed for curing at temperature.
Once that step is completed, the resulting wheel is machined to the desired finish and then polished. Mulliner already offers carbon fiber parts for various Bentley models, and the division has pledged to expand its line of products from this field. Over time, carbon fiber wheels will be more affordable, just like aluminum wheels became years after they first arrived on expensive cars.
On top of looking cool, each wheel brings a 6 kg (13.2 lbs.) reduction of unsprung mass per wheel when compared to aluminum. Reducing unsprung mass even on a heavy car like the Bentayga brings benefits to the vehicle's braking abilities, steering agility and overall stability. Even the contact patch of the tire is more consistent than that of a regular aluminum wheel, which provides greater confidence while driving.
The benefits do not stop here, as Mulliner explains that the new carbon fiber wheel can provide reduced tire wear due to the stiffness of the carbon fiber wheel. Its stiffness is equivalent to a 1-degree in camber per 1 G of force, according to British specialists. In comparison to an aluminum wheel, even one made through forging, it can lose up to a degree of camber due to flex during high-speed maneuvers.
The German TUV testing for this new wheel involved the most rigorous testing procedure for non-metallic wheels according to the new standards of the Technischer Überwachungsverei (Technical Inspection Association). Those tests include radial impact, lateral impact testing, and biaxial stress testing.
All the tests above simulate potholes, cobblestones, tire overpressure and even excessive torque. The impact test has demonstrated one of the key benefits of the carbon fiber wheel, in the form of its ability to allow a slow tire deflation in case of a severe impact. While aluminum wheels would just crack or shatter, leading to a sudden tire pressure loss, the carbon fiber wheel can absorb the impact and staying true to its shape, allowing for a safe and controlled stop.
Naturally, Bentley's Mulliner division took the new type of rim to the Nürburgring Nordschleife to put it through its paces.
The innovative technology promises repeatable quality and involves cutting carbon fiber cloth into predetermined shapes. Specialists then stack the weave segments in a specific manner, heat them with a special machine, and then drape them into the mold. Once that step is completed, the three-dimensional preforms get arranged into an even larger mold, where they get injected with resin and hardener, and are then placed for curing at temperature.
Once that step is completed, the resulting wheel is machined to the desired finish and then polished. Mulliner already offers carbon fiber parts for various Bentley models, and the division has pledged to expand its line of products from this field. Over time, carbon fiber wheels will be more affordable, just like aluminum wheels became years after they first arrived on expensive cars.
On top of looking cool, each wheel brings a 6 kg (13.2 lbs.) reduction of unsprung mass per wheel when compared to aluminum. Reducing unsprung mass even on a heavy car like the Bentayga brings benefits to the vehicle's braking abilities, steering agility and overall stability. Even the contact patch of the tire is more consistent than that of a regular aluminum wheel, which provides greater confidence while driving.
The benefits do not stop here, as Mulliner explains that the new carbon fiber wheel can provide reduced tire wear due to the stiffness of the carbon fiber wheel. Its stiffness is equivalent to a 1-degree in camber per 1 G of force, according to British specialists. In comparison to an aluminum wheel, even one made through forging, it can lose up to a degree of camber due to flex during high-speed maneuvers.
The German TUV testing for this new wheel involved the most rigorous testing procedure for non-metallic wheels according to the new standards of the Technischer Überwachungsverei (Technical Inspection Association). Those tests include radial impact, lateral impact testing, and biaxial stress testing.
All the tests above simulate potholes, cobblestones, tire overpressure and even excessive torque. The impact test has demonstrated one of the key benefits of the carbon fiber wheel, in the form of its ability to allow a slow tire deflation in case of a severe impact. While aluminum wheels would just crack or shatter, leading to a sudden tire pressure loss, the carbon fiber wheel can absorb the impact and staying true to its shape, allowing for a safe and controlled stop.
Naturally, Bentley's Mulliner division took the new type of rim to the Nürburgring Nordschleife to put it through its paces.
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