Rigid fork design guides

Technical guides for builders: measurements, standards and how to go from design to workshop. Every figure has its source.

• Fork disc brake mount dimensions: IS, post mount and flat mount

  Fork disc brake mount dimensions for IS, post mount and flat mount: hole spacing, A and B from the axle, threads, torque and max angles, with sources.

• Fork trail calculator: trail, offset and axle-to-crown

  Fork trail calculator: get trail and wheel radius from head angle, offset, rim and tyre, plus a converter between length L and axle-to-crown, with sources.

• Unicrown fork design: dimensions, blade bend and build measurements

  Unicrown fork design step by step: front and side view dimensions, the three-section blade bend and the measurements you need to build it, in tables.

• Fork axle-to-crown length: what it is and how to measure it

  Axle to crown length of a rigid fork: how to measure it, L versus direct AC with the formula, how BikeCAD gives it, and why it changes the frame geometry.

• Fork tyre clearance: crown, blades, fender and rotor

  Fork tyre clearance and fork fender clearance: what to measure under the crown, between the blades and at the rotor, with ISO tyre sizes, tables and sources.

• V-brake boss position on a fork: cantilever boss height for 700C

  V-brake and cantilever boss position on a fork per Shimano: 700C boss height measured along the blade, distance A, boss spacing and boss sizes.

• Crowned fork with a caliper brake: measuring the crown and positioning the brake hole

  Crowned fork caliper brake guide: how to measure the crown, how the offset results from crown rake, and the caliper brake hole position table, with sources.

• Segmented fork design: arm dimensions, blade angles and compound miters

  Segmented fork design without a crown: the inputs that define the arms (Hb, S, δ, θ), how arm length is calculated, and the outputs: blade angles, miters, cuts.

• BikeCAD and the rigid fork: what each dimension in the dialog measures

  What each letter in BikeCAD's rigid fork dialog measures: shoulder width, crown, L or AC length, offset and blade sections, in one table.

• Unicrown vs crowned vs segmented fork: the types of rigid fork compared

  Unicrown vs crowned fork, plus segmented: the parts each type of rigid fork uses, what you measure, what you fabricate and what to check before you choose.

• Suspension-corrected rigid fork: how to work out the axle-to-crown

  Suspension-corrected rigid fork for a frame designed around suspension: axle-to-crown minus sag, which offset to use, a worked example and a 29er warning.