Eunorau 4-Piston Hydraulic Brake Set 203mm

Eunorau 4-Piston Hydraulic Brake Set — Stopping Power Upgrade for Your eBike

A complete front + rear hydraulic brake replacement set with 4-piston calipers and 203mm rotors. Four pistons per caliper deliver substantially more clamping force than the two-piston units that come standard on most factory eBike builds. The 203mm rotor diameter is the next step up from the more common 180mm — bigger rotors run cooler on long descents and resist heat fade. Together, the upgrade is meaningful: shorter stopping distances, better feel in the wet, less rider fatigue on hilly rides, and consistent performance under heavier payload.

The set also includes integrated motor cut-off sensors at both levers. The instant you pull the brake, the motor cuts power — no more throttle-while-braking surprises, no more pedal-assist pushing into a stop. On a heavy 4″ fat-tire eBike at 40+ km/h, that motor cut-off is the difference between a controlled stop and a fight with the bike.

This is a full set — two calipers, two levers, two 203mm rotors, two pre-bled hydraulic lines (1050mm front and 1980mm rear), and the mounting adapters needed for installation. Pads are Shimano D02S/D03S compatible, which means service pads are available anywhere globally.

🇨🇦 Ships from Canada · Free shipping · 1-month Zeus warranty + Eunorau manufacturer coverage · 1-866-938-7580 — real humans answer

Compatibility — Read This Before Ordering

This brake set is designed for specific Eunorau frame and mount configurations. Confirm your model before buying. The wrong adapter or hose length cannot be exchanged for the right one after install.

Fits these Zeus catalogue Eunorau bikes:

• Eunorau Hunter X7 / FAT-HD 2.0
• Eunorau Fat AWD 3.0
• Eunorau Flash 1000W
• Eunorau Specter-S 1000W

Also fits these Eunorau platforms (listed by Eunorau internal model code — check the sticker on your seat tube or original packaging):

• D6
• DEFENDER · DEFENDER-S
• E-FAT-MN · E-FAT-STEP
• FAT-HS
• META275
• SPECTER-ST
• UHVO

Does NOT fit:

• Eunorau E-TORQUE series
• Eunorau JUMBO series
• Eunorau Cargo series
• Eunorau Trike series
• Eunorau Urus 2.0
• Eunorau R1 & R1 Plus
• Eunorau S1 Dirt Bike
• Eunorau eKids 24

Not sure if it fits your bike? Contact Zeus eBikes with your bike model and serial number, or call 1-866-938-7580. We will confirm fitment before you order — brake parts are not returnable once the hose seals are broken.

Why Riders Upgrade to This Set

• Stronger stopping power. Four pistons per caliper apply force more evenly across the pad than two-piston calipers, biting harder and modulating better. On a heavy fat-tire eBike with 280+ lbs of rider and cargo, that translates directly to shorter, more controlled stops.
• 203mm rotors run cooler. Bigger rotors have more thermal mass and more surface area to dump heat. On long downhills — mountain trail descents, river-valley drops, urban hills with the throttle off — smaller rotors get hot and lose bite. 203mm rotors stay consistent.
• Motor cut-off sensors at both levers. A safety feature that should be standard on every eBike. Pulling the brake instantly cuts motor power — no more throttle stuck, no more PAS pushing through the stop. The sensors are integrated into the levers, not zip-tied on as an afterthought.
• Pre-bled hydraulic lines. The system ships ready to install. No initial bleed required for most installs. (A bleed is still recommended after roughly 12 months as routine maintenance.)
• Globally serviceable pads. Shimano D02S/D03S pads are stocked at virtually every bike shop on earth. You will never be stuck waiting for replacements.

What’s in the Box

• 2 × 4-piston hydraulic calipers (front + rear)
• 2 × brake levers with integrated motor cut-off sensor
• 2 × 203mm disc rotors
• 2 × pre-bled hydraulic hoses — 1050mm (front) and 1980mm (rear)
• Mounting adapters for caliper-to-frame and caliper-to-fork attachment
• Installation hardware (bolts, washers)

Pads installed in the calipers are Shimano D02S/D03S compatible. Replacement pads are not included.

Installation

This is a bike-shop-level install if you have never replaced hydraulic brakes before. The lines ship pre-bled, which removes the most fiddly step, but the install still involves:

1. Removing the old calipers, levers, rotors, hoses, and motor cut-off sensors
2. Routing the new hydraulic lines through the frame (internal routing on some Eunorau models)
3. Mounting the new calipers with the correct adapter for your fork and frame
4. Installing the new rotors with the supplied bolts torqued to spec
5. Wiring the new motor cut-off sensors into the bike’s controller harness
6. Bedding-in the new pads with 20–30 progressive stops before any real riding

If you are mechanically confident with hydraulic brakes, plan for 60–90 minutes. If you are not, take it to your local bike shop — budget the labour. A botched brake install is not the place to learn.

Specifications

Shipping & Warranty

• Delivery: Ships within 3–7 business days from confirmation of order
• Shipping cost: Free Canada-wide shipping
• Tracking: Tracking email is sent automatically once the order leaves the warehouse
• Zeus Warranty: 1-month Zeus limited warranty (Canadian-handled) on the complete set
• Manufacturer Warranty: Eunorau accessory coverage applies on calipers, levers, and hydraulic components per Eunorau’s published terms
• Wear-and-tear exclusions: Brake pads, rotors with rider-induced contamination (oil, grease), and components damaged by improper bleed or install are not covered
• Returns: Brake hydraulic seals cannot be re-sealed once broken. Returns are accepted only on unopened, unused sets in original packaging

Zeus eBikes Canada — Free Canada-wide shipping on every accessory. Canadian-based team handling every warranty claim, fitment question, and pre-purchase consultation. Reach us at 1-866-938-7580 or zeusebikes.ca/contact.

Related from Zeus:

• Eunorau Hunter X7 / FAT-HD 2.0 →
• Eunorau Fat AWD 3.0 →
• Eunorau Flash 1000W →
• Eunorau Specter-S 1000W →
• Browse all eBike accessories →