DRUM BRAKE ARCING
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 is now offering Brake Drum Turning and Brake Shoe Arcing. We used to do this “back in the day” and we were “strongly urged” to start offering the service again by AHRMA Racers
Vintage Moto Cross, Cross County, Flat Track and Road Race
Cafe Racer, Bobber, Street Tracker, Custom Builds and Street Bikes
Ours is a unique 2 stage process; We 1st cut the drum so it's concentric (round), lining is flat wih good firesh surface. 2nd we cut the shoes to match the new drum diameter for optimum shoe/drum contact. This results in optimum drum to shoe contact.
The difference is quite often amazing!
Here's what we need:
- Complete clean wheel (with or without tire – shipping without it is a lot cheaper).
- Wheel should be trued with spokes properly adjusted. (spokes can easily pull a drum egg shaped). It is critical to have all spoke & rim work competed prior to Brake Arc!
- Wheel should be clean inside and out. Clean up at RT is extra cost
- Axle (must be straight) It is essential the axle is straight or it will cock the backing plate causing poor performance. We check it for straightness and we use it in the Arcing process as well.
- Complete clean and lubed Backing Plate.
- Good brake shoes (nothing oily or worn out). New OEM or Aftermarket Shoes are recommended, there has been great improvement in friction material over the years.
Brake Arc Service: $200 per Brake Drum/Shoe Set
Extra Shoes (spares) Arc to match Drum: $75/set
Clean-Up fee accessed to dirty or greasy drums or backing plates!
Typical turn-around is about a week but give us a call to make sure.
►Brake Arc Service Request Form
INSTALLATION PROCEDURE - (all drum brakes)
- 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. This centers the backing plate.
- There are two major types of front axle systems; Full Width Spacers or Axle Pinching Type. Full Width Spacers are commonly 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 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.
- 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 a very good leverage. Honda or Yamaha levers had much better stopping power.
Good luck and good stopping,
►YZ465 Brake Arcing
►Floating Brakes Tech Tip
Brake Arc or Vintage Questions? Email Matthew Wiley