The original C5 brakes are its weak point. The front caliper acts on a nylon rim that softens when hot, and the rear drum (on the right-hand wheel only) tends to grab. Owners have fitted disc brakes, front and rear, to improve stopping power and to avoid overheating the front rim.

https://www.thingiverse.com/thing:6699160

• A disc conversion changes the parts the 1983 rules and the handbook expect (“use only the specified brakes”). That's a consideration for road use; see The law.
• The front wheel is nylon. Any disc mounting must transfer braking torque without stressing the hub.

• Chas and Pep developed a front disc brake kit (c5owners forum, 2013), which kamztrad used on a 36 V C5.
• A rear disc brake conversion has also been tested on the c5owners forum.

Front brake · Front brake blocks · Brake back plate · Rear brake shoe set · Front wheel

• c5owners.com forum (closed to new posts, still readable):
  • Front disc brake
  • Front wheel disc brake mod
  • Back wheel disc brake
  • Rear disc brake testing
  • 36 volt C5: kamztrad, 2013
• The Unofficial Sinclair C5 Service Manual, “Known Problems” (front rim softening, rear brake locking)