The Dominion A4 is Hayes' top-end 4-piston brake for enduro, downhill and eMTB riding – built for heavy, repeated braking on long descents without fading.

Highlights

  • Four Ø17mm pistons in a cold-forged caliper
  • DOT 5.1 fluid, Kevlar hose, two-stroke dual-port bleed system
  • Tool-free reach adjustment and flip-flop lever orientation (left or right lever)
  • Comes pre-bled, with Sintered T100 and Semi-Metallic T106 pad sets included
  • Sold as one complete lever-and-caliper brake, fitted front or rear

Compatibility & fit

Post mount only – the caliper bolts to a post mount bracket matched to your rotor size (sold separately; see our post mount and IS mount bracket listings). Rotor also sold separately – the Hayes D-Series rotor is designed to pair with this brake. DOT 5.1 fluid only; never mix with mineral oil or DOT 4. Supplied with a full-length Kevlar hose that's trimmed and re-bled to fit front or rear during fitting – a job for the Tune workshop.

Options

ColourWhat differs
Black/Bronzebronze caliper and lever hardware
Stealth Black/Greystealth black and grey hardware
Hayes Bicycle Group's two-year warranty covers defects in materials and workmanship, and Hayes' limited lifetime leakproof warranty covers fluid leaks from the master cylinder and caliper after the first two years. Normal wear and tear, crash damage and labour aren't included. For warranty support, return the product to Tune Cycles and we'll manage the claim with Hayes' Australian distributor. This is in addition to your rights under the Australian Consumer Law, so keep your proof of purchase.
  • 4-piston caliper, DOT 5.1 fluid, Kevlar hose
  • Tool-free reach adjustment, flip-flop lever orientation
  • Pre-bled, two pad sets included (Sintered T100 + Semi-Metallic T106)
  • Post mount only – bracket and rotor sold separately
  • One lever + caliper, fits front or rear
BrandHayes
Pistons4 × Ø17mm
FluidDOT 5.1
MountPost Mount (bracket sold separately)
HoseKevlar
Coloursee Options table
SKU DTW-HBG-95-36115-K00-PAR
Brand Hayes