Choosing a reliable rear brake assembly is essential for safe and consistent stopping power on pit bikes. This guide reviews five aftermarket rear brake master cylinders and caliper kits designed for 50cc through 150cc Chinese pit bikes and popular brands. Each option focuses on compatibility, ease of installation, and braking performance. Use the buying considerations below to compare mounting options, wheel shaft sizes, and pad compatibility to find the best fit for your ride.
| Product | Wheel Shaft Size | Includes | Approximate Fitment |
|---|---|---|---|
| FVRITO 12mm Rear Disc Hydraulic Brake Master Cylinder Caliper Assembly | 12mm | Brake fluid compatible, caliper, pad set | 50cc–150cc Pit Dirt Bikes |
| HIAORS Rear Brake Assembly Master Hydraulic Cylinder Caliper | 15mm | Caliper, replaced disc brake pad | SSR 125cc/110cc/50cc–70cc Dirt Bikes |
| Aynaxcol 15mm Rear Brake Assembly for SDG SSR | 15mm | Rear disc brake assembly, pad installed | SDG SSR 107/110/125 |
| Rear Brake Assembly Master Hydraulic Cylinder Caliper Kit | Applicable to 110cc class | Master cylinder, caliper, kit components | 110cc–125cc Pit Bike range |
| 12mm Rear Disc Hydraulic Brake Master Cylinder Kit | 12mm | Caliper assembly with pad, brake fluid | 12mm wheel shaft bikes |
FVRITO 12mm Rear Disc Hydraulic Brake Assembly
The FVRITO rear brake kit is designed for a wide range of Chinese pit bikes, including SSR, Taotao, Coolster, Roketa and Atomik models. It features a 12mm wheel shaft compatibility and a mounting hole spacing around 42–50mm. The kit includes a master cylinder, caliper, and pad set, with a ready-to-install configuration that aims to reduce custom fitting effort. A 500mm brake oil line is provided to accommodate common frame layouts. Suitable for riders upgrading from drum brakes or seeking improved stopping control on small-displacement bikes.
Key considerations include verifying wheel shaft size, ensuring the 12mm designation matches your rear axle, and confirming mounting hole spacing fits your bike’s rear caliper bracket. The kit’s broad compatibility list makes it appealing for mixed-brand builds, but users should double-check the exact model and year of their dirt bike. Brake feel and lever feel will depend on the brake fluid type used and the pad material chosen.
HIAORS Rear Brake Assembly Master Cylinder Caliper
The HIAORS kit targets SSR and other 125cc–110cc dirt bikes, representing a practical option for riders seeking a direct replacement for worn calipers and master cylinders. It includes a complete brake assembly with a replaced disc brake pad. The 15mm wheel axle specification is highlighted, which is common on many hot-rodded pit bikes. Installation tends to be straightforward, with standard bolt patterns and alignment requirements.
From a performance standpoint, this kit favors reliability and ease of maintenance. It provides a single-package solution, reducing the need to source individual components. Potential considerations include confirming that the 15mm axle is compatible with your bike’s rear hub and that the caliper’s mounting points align with your brake mount. Pad wear will influence stopping power, so inspect pad material and thickness upon installation.
Aynaxcol 15mm Rear Brake Assembly for SDG SSR
Designed for 15mm rear wheel shafts, this Aynaxcol kit is tailored to SDG and SSR platforms, including 107 and 110/125 models. The package includes a rear disc brake assembly with a brake pad already installed, plus an additional pad in some listings. The mounting hole center spacing is specified to match standard 63mm setups, aiding precise fitment on compatible frames. It’s positioned as a ready-to-install option for riders who want a clean, factory-feel upgrade without extensive modification.
When evaluating this option, consider wheel shaft size precision, pad type, and the condition of the existing brake line routing. Compatibility with your bike’s brake line length and reservoir position matters for avoiding kinks or interference with exhausts or suspension components. Pad material grade can affect initial bite and fade resistance during extended braking sessions.
Rear Brake Assembly Master Hydraulic Cylinder Kit
This kit emphasizes wide compatibility across common 110cc–125cc dirt bikes, including SSR, KLX, BBR, CRF, TTR and SDG model families. It features an adjustable bolt spacing to fine-tune fitment, which helps align the assembly with varied frame designs. The package includes all necessary components for straightforward installation, reducing the need for custom fabrication. It is ideal for riders seeking a technically precise upgrade that adapts to several bike geometries.
Prospective buyers should verify the available clearance around the brake line, reservoir, and exhaust routing in their pit bike. Adjustability is a key advantage, but improper spacing can cause misalignment or uneven pad wear. Consider pairing with compatible pads and using the correct brake fluid type to maximize performance and longevity of the caliper seals.
12mm Rear Disc Hydraulic Brake Master Cylinder Kit
This 12mm kit is clearly labeled for bikes with a 12mm rear wheel shaft, clearly excluding 15mm configurations. It provides a complete rear brake master cylinder and caliper assembly with installed brake pad, plus a free extra pad. The included 500mm brake line length accommodates many common frames, making it a versatile upgrade for mixed-brand builds that use 12mm axles. It’s a practical choice for riders who want a plug-and-play solution with minimal parts shopping required.
When considering this option, confirm your wheel shaft size and ensure your caliper mounting points match the bike’s frame. The extra pad is a helpful contingency for future maintenance. Regular inspection of line routing and reservoir position helps maintain consistent brake feel and avoid fluid leaks or air ingress during use.
Buying Guide: Key Purchase Considerations
Choosing the right rear brake assembly involves balancing fit, performance, and maintenance. Consider the following factors to compare options effectively:
- Wheel shaft size: Ensure the kit matches your bike’s rear axle diameter (12mm vs 15mm). Mismatches prevent installation and can compromise safety.
- Mounting hole spacing: Verify center-to-center spacing to align with the caliper bracket on your frame. Incorrect spacing can cause misalignment and uneven pad wear.
- Pad compatibility and replacement: Confirm whether the kit includes pads or requires separate purchases. Pad material affects bite, fade resistance, and durability.
- Line length and routing: Check brake hose length (common lengths like 500mm or Braun) and routing space near frames, exhausts, and suspension components to avoid interference.
- Fluid compatibility: Use the correct brake fluid type for seal longevity and optimal braking performance. Bleed procedures may vary by kit.
- Installation effort: Some kits are “plug-and-play,” while others may need bracket adapters or minor fabrication. Read product notes carefully.
- Brand and model compatibility: Kits often list broad compatibility, but cross-check with your specific bike model, year, and locale to ensure part interchangeability.
- Maintenance support: Availability of replacement pads and seals should influence long-term value, especially for riders who ride aggressively or frequently ride in wet conditions.
Overall, the best choice depends on your bike’s wheel shaft size, the frame’s caliper mounting geometry, and how you value ease of installation versus fine-tuning capability. For riders seeking a straightforward upgrade, kits with included pads and longer hoses can reduce setup time. For enthusiasts who want precise alignment and adjustable fit, units offering bolt-spacing customization and detailed mounting specs are advantageous.