Cantilever brake bosses (locating)

Whether you're designing a bike for V-brakes (otherwise known as direct pull brakes) or for traditional center-pull cantilever brakes, you'll want to choose the Cantilever option in the rim brake section of the Brake dialog box. In BikeCAD we can distinguish a center-pull brake from a direct pull brake by entering a smaller value for the AL dimension.

Cantilever brake bosses are included anytime a cantilever brake is selected.

You'll need to adjust the location of the cantilever brake bosses when new wheel sizes are chosen. The placement of the cantilever boss is controlled by either the X or the D dimension. Dimension X is the distance from the cantilever boss to the rear axle measured perpendicular to the cantilever boss. Dimension D is the direct distance from the tip of the cantilever boss to the rear axle. These dimensions can be shown by selecting the Cantilever bosses subtab in the Braze-on tab of the Dimensions dialog box.

Another reason you may need to adjust the position of the cantilever boss is if you are using a brake other than a traditional cantilever or V-brake. For example, U-brakes or brakes like the Paul centerpull brake with braze-on option will require bosses to be mounted above the brake pads, not below the pads as they normally are. If you wish to model one of these brakes, enter a negative value for PY. BX and BW will then control the size of the brake arm. A larger value for BW will likely be required to reach the brake pad.