2026 F1 Tyres and Wheels: 18-Inch Rims and Magnesium Alloy

The wheels and tyres of a Formula 1 car are the only contact points between the machine and the track surface. Every force that accelerates, brakes, or turns the car must pass through four tyre contact patches, each roughly the size of a sheet of paper, and the properties of the tyre at those contact patches determine how much of the car’s aerodynamic and mechanical potential can be converted into actual performance. In 2026, the 18-inch wheel and tyre specification introduced in 2022 continues, and the regulations governing wheel construction and tyre dimensions remain consistent with the previous era’s framework, with the performance characteristics of the compounds adjusted by Pirelli to suit the different load conditions the lower-downforce 2026 car generates. For the full picture of the 2026 car’s design changes, see our guide to 2026 F1 car design.

The 18-Inch Wheel Specification

Formula 1 switched from 13-inch to 18-inch wheel rims in 2022, ending a decades-long tradition of using the small-diameter wheel that had become one of the sport’s most distinctive visual signatures. The change was driven by a combination of commercial relevance, since road cars have long used much larger diameter wheels, and technical merit, since the larger rim diameter allows the tyre sidewall to be much lower in profile, which changes the tyre’s structural behavior and its response to lateral loads in ways that affect car performance and handling.

Low-Profile Sidewalls

With an 18-inch rim diameter, the tyre’s sidewall height is considerably lower than the 13-inch era’s tall, flexible sidewalls. A low-profile sidewall is stiffer laterally and deflects less under cornering loads, which means the tyre’s contact patch position is more directly controlled by the car’s suspension geometry rather than by the sidewall’s elastic deformation. This greater rigidity makes the tyre’s aerodynamic behavior more predictable but also reduces the compliance that the tall 13-inch sidewall provided, which had served as an additional suspension element absorbing small road surface irregularities that the mechanical suspension did not fully isolate.

The transition to 18-inch wheels required teams to adapt their suspension designs to handle the loss of tyre sidewall compliance and to manage the different tyre load response that the stiffer sidewall produces. In 2022, several teams initially struggled with specific vibration modes excited by the stiffer tyre construction at particular circuit speeds, which produced a phenomenon where the car would bounce or porpoise at certain frequencies that the previous tyre construction had naturally damped. Managing these vibrations through damper tuning and suspension setup was one of the early engineering challenges of the 18-inch era, and the 2026 regulations maintain the 18-inch specification as the established baseline for which teams have now developed mature understanding. How suspension interacts with the tyre’s stiffness characteristics is covered in our article on 2026 F1 suspension changes.

Brake Disc Diameter Constraints

The 18-inch wheel diameter provides more physical space within the wheel for the brake disc and caliper assembly. The 2026 regulations specify maximum and minimum permitted brake disc diameters for the front and rear axles: front discs between 325 and 345 millimeters, and rear discs between 260 and 280 millimeters. These ranges allow teams some choice in their brake disc specification, selecting a disc diameter within the permitted range that best suits their braking system’s thermal management requirements and their target braking performance level for the specific circuit.

Larger disc diameters within the permitted range provide more thermal mass and more swept area for the brake pads to contact, which improves the disc’s ability to absorb and store heat energy during a braking event and reduces the thermal load per unit area on the disc surface. Teams running higher-downforce aerodynamic configurations, which produce higher-speed corner approaches and therefore more kinetic energy to dissipate in each braking event, may prefer the larger end of the permitted disc diameter range. Teams optimizing for minimum unsprung weight might choose the smaller end of the range where the braking performance is adequate for the circuit’s demands.

Magnesium Alloy Wheel Construction

The wheel rim itself, the structural component that the tyre mounts onto and that transmits the braking, cornering, and driving forces from the tyre to the suspension, is manufactured from magnesium alloy in 2026. Magnesium alloy is specified because it offers a significantly better strength-to-weight ratio than aluminum alloys for the structural loading conditions that an F1 wheel experiences, allowing wheel rims that meet the stringent load requirements of racing to be produced at lower mass than equivalent aluminum designs would permit. This weight saving contributes to the overall 768kg minimum weight target discussed in our article on F1 minimum weight 2026.

Why Magnesium Over Aluminum

Magnesium is approximately 35 percent less dense than aluminum while maintaining comparable strength in the alloy forms used for structural components. For a wheel rim that must withstand the large bending and torsional loads imposed by high-speed cornering, heavy braking, and kerb impacts, this density advantage translates directly to mass savings that are aerodynamically and dynamically beneficial. Wheel mass is unsprung mass, meaning it is not supported by the car’s springs and dampers and must be accelerated and decelerated by the suspension itself during wheel travel. Lower unsprung mass allows the suspension to respond more quickly to road surface irregularities, improving the consistency of the tyre contact patch and the car’s handling over variable track surfaces.

Magnesium alloy also has good thermal conductivity relative to some alternative materials, which assists in managing the heat generated by the brake disc that radiates and conducts into the wheel rim during extended braking events. Managing the temperature of the wheel rim is important because the tyre’s air pressure is sensitive to the temperature of the air within the tyre, and if the wheel rim transfers excessive heat to the tyre’s inner liner, the tyre pressure rises in a way that changes its contact patch shape and pressure distribution in ways that may not be optimal for handling performance.

Wheel Safety and Retention

The regulations specify the structural test requirements that wheel rims must meet before they can be used in competition. These tests include impact load cases that represent the forces generated when a car runs over a kerb at racing speed, lateral load cases representing the highest cornering forces the wheel will experience, and torsional load cases representing the peak braking and driving torques transmitted through the wheel. A wheel rim that fails any of these tests cannot be used in competition, and teams must recertify their wheel rim designs when they make changes to the rim’s geometry or material specification.

Wheel retention in crashes is addressed through the tethering system that connects each wheel assembly to the car’s structure. These tethers must be strong enough to retain the wheel during impacts where the suspension is damaged, preventing the wheel from separating and becoming a projectile hazard to other drivers, spectators, or marshals. The tether specifications in the 2026 regulations maintain the approach established in the previous era, with defined load requirements for the tethers at each corner of the car that account for the mass of the wheel assembly and the expected severity of impact forces in the most demanding crash scenarios the regulations are designed to protect against.

Pirelli Tyre Compounds for 2026

The tyres themselves are supplied exclusively by Pirelli under their agreement with Formula 1’s commercial rights holder, and Pirelli develops the compound ranges for each season in response to the technical and sporting requirements of the current car generation. For 2026, Pirelli has developed compounds calibrated for the different load conditions the lower-downforce, lighter cars will generate compared with the 2022-to-2025 generation.

Adapting to Lower Aerodynamic Loads

The 30 percent reduction in aerodynamic downforce means the tyres in 2026 experience lower peak lateral loads in cornering compared with the previous generation at equivalent corner speeds. Lower aerodynamic downforce also means that the normal force pressing the tyre against the track surface is lower, which affects the tyre’s grip generation mechanism: tyres generate grip through a combination of mechanical interlock between the tyre tread and the road surface and rubber deformation at the microscopic scale, both of which are sensitive to the vertical load applied to the contact patch. Pirelli’s compounds for 2026 are developed to operate effectively at the load levels the lower-downforce car generates rather than being optimized for the peak loads the high-downforce previous generation imposed.

The lower aerodynamic loads in 2026 also reduce the rate at which the tyres generate heat during cornering. Tyre heat generation is related to the work done by the tyre’s deformation under load, and lower loads mean less deformation and less heat generation per unit of distance traveled. Pirelli accounts for this in their compound selection for 2026, choosing compounds whose operating temperature range suits the thermal conditions the lower-load car generates. A compound that worked well in the high-load thermal conditions of the 2022-to-2025 car generation might not reach its optimal operating temperature as quickly in the lower-load 2026 car, requiring different tyre management approaches and potentially different compound choices at circuits where tyre warming was previously straightforward. The 2026 F1 car dimensions that define the car’s overall size and weight also influence the load conditions Pirelli’s compounds must handle.