DRUM BRAKE ARCING 
and INSTALLATION

 

The difference between winning and losing races or survival on the street can easily come down to something as simple as brakes. Many drum brakes are mushy with poor stopping power.

Race Tech has been performing Brake Drum Turning and Brake Shoe Arcing for over 35 years. Available for:

Vintage Motocross, Cross County, Flat Track, Road Race, Cafe Racer, Bobber, Street Tracker, Custom Builds and Vintage Street

Ours is a unique two stage process; We first cut the drum so it is concentric and flat. Then we cut the shoes mounted on the backing plate to match the new drum diameter. The result is optimum contact.

 

The difference is often quite amazing!

Brake Arc Review Motorcycle Classics Magazine 

Here's what we need:

  1. Complete wheel (without the tire is best – shipping is a lot cheaper).
  2. Wheel should be trued with spokes properly adjusted (spokes can easily pull a drum egg shaped). All spoke and rim work must be competed prior to Brake Arcing!
  3. Complete clean and lubed backing plate with shoes. Wheel and brake backing plate should be clean inside and out. Clean up at RT costs extra.
  4. Good brake shoes (nothing oily or worn out). New OEM shoes are generally the best.
  5. Axle - A straight axle is critical! A bent axle will cock the backing plate causing poor performance. Bent axles are pretty common. You must send your axle in as we check it for straightness. Also it is used in the Arcing process.
  6. Please do not send us any extra hardware such as axle nuts, spacers, etc.

Brake Arcing Service: $250 per Brake Drum/Shoe Set

Arc Extra Shoes to match drum: $75/set

Clean-Up fee for dirty drums or backing plates (if required) $50

Typical turn-around is about 10 days but give us a call to make sure: 951-279-6655 option 5

  ►Brake Arc Service Request Form


 

INSTALLATION

  • Center the backing plate. Mount the front wheel on the forks. Before you tighten the axle, spin the wheel and grab the front brake lever. While keeping the lever held firmly tighten the axle.
  • There are two major types of front axle systems; Full Width Spacers or Axle Pinching Type. Full Width Spacers are common on less expensive or older models. The Axle Pinching Type typically tightens into the left hand leg while the right side allows the fork tubes to be parallel.
  • For the Axle Pinching Type check that the axle can freely move in the pinch. Take the bike off the stand and pump the forks with the axle pinch loose. This aligns the fork legs. Tighten the axle pinch clamp.

 

NOTES:

  • If you've followed this procedure and the front brake lever action feels positive before you tighten the axle but feels mushy afterwords you either have a bent axle or the surface of the fork leg or backing plate is not square to the axle.
     
  • If you have dual or quad leading shoes do not adjust the tie-rod between the brake cams after the shoes have been arced.

  • Early Magura levers were cool but they didn't have very good leverage. Honda or Yamaha levers had much better stopping power.

Good luck and good stopping,
Paul Thede

►YZ465 Brake Arcing

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►Brake Arcing Testimonial

►Brake Arc Review in Motorcycle Classics Magazine

Brake Arc or Vintage Questions? Email Matthew Wiley

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