Old Britts
Commando Front Disc Upgrade Information

You can make a stock Commando front disc stop almost as good as a new bike with a few modifications.

  • Blanchard grind the rotor. Blanchard grinding is the process of truing up the braking surfaces. First the mating surface between the rotor and the hub is ground flat, and then the two sides of the rotor are ground parallel to the mating surface. The rotor now runs true without any wobble inside the caliper. For more information on upgrading the front rotor see NORTON, Rotor, Disc Brake.
  • Lightening the rotor. This takes off around lb. and provides better stopping in the wet and under heavy breaking. On modern cars that offer an upgraded rotor that have slots in them, the slots are to relieve the gas buildup between the brake pads and the rotor. The slots also help dissipate water. We substitute holes for the slots which work like the slots, but provide more of a vintage look.
  • Rebuild the caliper and upgrade the brake pads to a modern compound. For more information on rebuilding the caliper see Commando Caliper Rebuild Instructions.
  • Upgrade the master cylinder to a 13mm piston. The original master cylinder was detuned by the factory because they thought a too powerful front brake would cause trouble. The reverse is true where a wimpy front brake is likely to cause trouble. For more information on this upgrade see Upgrade Commando Master Cylinder to 13mm Bore.
  • Upgrade the brake lines to braided stainless steel. The stock rubber lines expand slightly with the upgraded master cylinder, so to take full advantage of the increased pressure, a braided steel brake line is required.

If you do all the above you will have a one or two finger brake.

The estimated costs for the above modifications, depending on the options you select, are:

  • Upgrade rotor (part # 06-1885/CGL) is $110.00.
  • Rebuild caliper (part # 06-1927/CRO) is $241.46.
  • Upgrade master cylinder (PART # 06-1939/CUE) is $160.00.
  • Braided steel line for US bars, 25" (06-3507/A) is $57.00.

the above prices are current as of 07/22/06.

Return to Old Britts home page ….. Technical Articles

This page was written and designed by F. H. Eaton & Associates if you have any questions or comments please contact us at info@fheaton.com