The wheels are IFMAR standardized using the wheel hex offset. The tires function countersunk center area that allows the wheel nut to sit deeper in the wheel. The tires are perfect for high-competition race. They feature interior reinforcement ribs to offer security and resist deformation, yet they truly are created from a flexible material to produce durability and withstand impacts. Along side it of the wheel is aerodynamic for optimum performance. The wheels had been built to provide maximum traction. The wheels feature a 12mm internal hex. Group of 10 (5 set)