Model: 4 piston

Brake pads: same as hope pads, E4 M4 resin pads

Brake oil: mineral oil

Rotor size: 160/160mm

Accessories: with oil pin and screws

Oil needle and olive tip model: BH90

Oil hose diameter: 5mm

Suitable for: ONIRII 4 piston hydraulic brakes are suitable for XC, climbing, DH, AM and other mountain bikes or action bikes

After installing CD-02, CD-03, six-hole discs only for road bikes and XC mountain bikes
Weight: Single front brake:234g/0.5 lb (wight )   82cm/32 inch (length)
Single rear brake:  250g/0.55lb  (wight )   145cm/57 inch (length

One pair of brakes:  483g/1.06 lb 


*The 4 piston brakes you received are already installed with pads and filled with oil inside.

What changes have we made with the new upgraded 4-piston brakes?
New brake handle:
① Clamping ring 
② Brake stroke adjustment screw, the model is M5(Upgraded new features)
③ Clamping ring screw
④ Oil filling screw
⑤ Oil type 
⑥ CNC brake cylinder 
⑦ Brake bearing rotation point 
⑧ CNC brake handle grip


Brake handle screw model frequently asked by buyers

Caliper Screws

The interior of the brake handle has been updated with an oil bladder structure

This 4-piston brake uses CNC one-piece 4-piston caliper, which maintains good stability and rigid braking power while also minimizing weight. The brake interior uses imported seals, which are more heat and cold resistant and can withstand temperatures as low as -40° and as high as 220°


Old brake handle:



Caliper part:
① CNC one-piece calipers
② Heat dissipating brake pads(Upgraded new features)
③ Pad Bolts
④ Oil hose screw
⑤ Oil Injection Screw
⑥ Piston cover


ONIRII M4 hydraulic brakes feature a CNC integrated brake handle, bearing rotation points for enhanced braking feel, upgraded cylinders to provide sufficient oil volume, and mineral oil for the brake fluid.




Product installation effect