Steering geometry (ISO recommendations)

The International Organization for Standardization has a few recommendations for bicycle steering geometry and it lists them in Annex A of ISO document 4210-2. In the first section of Annex A it is recommended that the head angle of a bike should fall somewhere between 65 degrees and 75 degrees. In the second section a diagram is shown which locates a point at the intersection of the steering axis and a vertical line drawn through the front axle. The ISO recommends that this point should be located above the ground by a distance no less than 15% of the wheel radius and no more than 60% of the wheel radius.

In the Components >> General tab of the Dimensions dialog box we have a dimension listed as ISO 4210-2: Annex A, b) . By displaying this dimension we will see the point of intersection described above. We will also see points representing 15% and 60% of the wheel radius. As you can see, because the point of intersection labeled 0.54R falls between the points labeled 0.15R and 0.6R, we know that our design satisfies this ISO standard.