Grab on to the lightest JOES Steering Wheel ever. You won't loose your grip on their shot peened, no slip surface. It is drilled to reduce weight and is available with a black anodized finish or bare aluminum. Flat wheels have a slight dish, they are designed for the center to sit flush when lying flat. The slight dish improves the durability of the wheel to prevent bending. Tube diameter is 1 1/8".