European Hub & Brake repairs -tips

Knott or Al-Ko – HOW DO I MEASURE THE BOLT PATTERN ON EUROPEAN BRAKE DRUMS?

Bolt Circle Bolt pattern involves two different dimensions. Bolt circle indicates how many bolt holes a drum has and the diameter of a bolt circle. A bolt circle may for example be 4 × 100. Such a bolt circle indicates a drum with four bolts and the number of millimeters which is the circle’s diameter (100 in this example). Drum with four bolts A drum with four bolts you can measure bolt circle from the edge of the bolt hole to bolt hole inner edge straight across the hub bore or center hole to center hole straight across the hub bore. Drum with five bolts A drum with five bolts you measure from the center of one hole straight across the hub bore to an imaginary line midway between the two holes on the opposite side.

Variant, Brian James, Ifor Williams, Brenderup or Nugent – they all use a four or a five stud pattern.