Product Introduction

A bicycle bottom bracket is one of the key rotating components in the bicycle drivetrain system. It is installed inside the bottom bracket shell of the frame and works with the crank arms, chainring, pedals, and chain drive system. When the rider pedals, the bottom bracket axle supports the crankset rotation and helps transfer pedaling force into the drivetrain.

The product shown is a metal bottom bracket assembly with a black central axle, silver threaded cups, bearing area, and square-style crank connection ends. Its compact structure is suitable for bicycle assembly, drivetrain repair, crankset installation, and replacement part supply.

This type of bottom bracket is widely used in traditional bicycles, city bikes, commuter bikes, folding bikes, and some light e-bike projects. KONSTUN can support related metal component manufacturing, surface finishing, sample development, and batch production based on customer drawings or samples, while the final structure and material can be confirmed according to the actual bicycle model and assembly requirements.

Key Specifications & Parameters

Product Type: Bicycle bottom bracket assembly

Main Product Forms: Bottom bracket axle, threaded bottom bracket, square taper bottom bracket, crankset axle component, bicycle drivetrain rotating part

Material Options: Steel, aluminum alloy, stainless steel, or other suitable materials according to product structure

Processing Methods: CNC machining, turning, threading, drilling, grinding, polishing, assembly, and surface finishing

Surface Treatment Options: Polishing, plating, black coating, anti-rust treatment, anodizing for aluminum parts, or other requested finishes

Color Options: Black, silver, natural metal finish, plated finish, or customized appearance based on product design

Structure Features: Central axle, threaded cups, bearing area, crank connection ends, lock ring or fixing structure

Drawing Support: 2D drawings, 3D files, CAD, PDF, STEP, STP, or physical sample reference

Logo Option: Laser engraving, printed marking, or packaging branding depending on customer requirements

Packaging: Individual protective packaging, carton packaging, or packaging based on repair kit and batch order needs

Application Fields: City bikes, commuter bikes, folding bikes, e-bikes, bicycle repair parts, crankset assembly, drivetrain components

Product Highlights

Core Drivetrain Component
The bottom bracket sits at the center of the bicycle frame and connects directly with the crankset. It is a small but important part that affects pedaling rotation, drivetrain assembly, and daily riding performance.

Threaded Cup Structure
The threaded cup design allows the component to be installed into the frame bottom bracket shell. This makes it suitable for bicycle repair, replacement, and assembly projects where a secure central axle structure is required.

Crankset Connection Support
The axle ends are designed to connect with crank arms. This helps the left and right crank arms rotate together and transfer pedaling force through the chainring and chain system.

Compact Metal Assembly
The product combines axle, cup, and bearing-related structures in a compact form. It is easy to recognize, practical for bicycle maintenance, and suitable for repair part suppliers or bike assembly projects.

Suitable for Multiple Bike Types
This bottom bracket component can be used for city bikes, commuter bikes, folding bikes, general bicycles, and some e-bike applications depending on the frame and crankset design.

Replacement and OEM Use
The product is suitable for both new bicycle assembly and replacement part supply. Material, surface finish, packaging, and related details can be arranged according to the customer’s project needs.

Main Functions

Crankset Rotation Support
The bottom bracket allows the crank arms to rotate around the center axle. It supports smooth pedaling movement and helps the rider transfer force into the bicycle drivetrain.

Frame and Crank Connection
The component is installed in the bottom bracket shell of the bicycle frame and connects with the crank arms on both sides. It acts as the central connection point between the frame and drivetrain system.

Pedaling Force Transfer
When the rider pedals, force is transmitted through the crank arms, bottom bracket axle, chainring, and chain. A properly matched bottom bracket helps keep this transmission structure stable during riding.

Bicycle Repair and Replacement
Bottom brackets are common replacement parts in bicycle maintenance. This product can be used when the original bottom bracket is worn, damaged, loose, or no longer suitable for the crankset.

Drivetrain Assembly Support
For bicycle production and repair kits, the bottom bracket is an essential part of crankset installation. It helps complete the central drivetrain assembly of the bicycle.

Compatibility Development
Different bicycles may require different axle interfaces, cup structures, or material options. The product can be developed according to frame design, crankset type, and customer sample requirements.

Specific Application Scenarios

City Bike Assembly
City bicycles need practical and reliable drivetrain components for daily riding. A bottom bracket assembly supports smooth crank rotation for short-distance commuting, casual riding, and urban transportation.

Commuter Bicycle Repair
Commuter bikes are used frequently and may require drivetrain maintenance after long-term use. Bottom bracket replacement helps restore crank rotation and improve the riding feel.

Folding Bike Components
Folding bikes often use compact frame structures and specific drivetrain layouts. A suitable bottom bracket helps connect the crankset within the limited frame space.

E-Bike Drivetrain Projects
Some e-bike models still use traditional crankset and pedal drive structures. The bottom bracket can be selected according to the frame shell, crank interface, and drivetrain arrangement.

Bicycle Repair Shops
Bike repair shops and maintenance suppliers can use bottom bracket assemblies for replacement, upgrade, and general service needs across different bicycle models.

OEM Bike Part Supply
For bicycle brands and accessory distributors, bottom bracket components can be supplied as part of drivetrain kits, replacement parts, or complete bicycle assembly programs.

FAQ

Q1: What is a bicycle bottom bracket used for?
A1: A bicycle bottom bracket is installed in the center of the bike frame and connects the crank arms, allowing the crankset to rotate during pedaling.

Q2: Is this product a complete crankset?
A2: No. This product is a bottom bracket assembly. It works with crank arms, chainrings, pedals, and other drivetrain parts, but it is not a complete crankset.

Q3: Can it be used for city bikes and commuter bikes?
A3: Yes. It can be used for city bikes, commuter bikes, folding bikes, general bicycles, and some e-bike projects depending on the frame and crankset compatibility.

Q4: What materials can be used for this bottom bracket?
A4: Steel, aluminum alloy, stainless steel, or other suitable materials can be selected according to the structure, application, and customer requirements.

Q5: Can the axle interface be changed?
A5: Yes. The axle end structure, cup design, thread style, and related assembly details can be developed according to drawings, samples, or project requirements.

Q6: Can you provide surface treatment for the metal parts?
A6: Yes. Plating, polishing, black coating, anti-rust treatment, anodizing for aluminum parts, and other suitable finishes can be arranged based on the product design.

Q7: What information should I provide for quotation?
A7: Please provide drawings, samples, material requirements, surface finish, quantity, packaging needs, and key assembly information such as frame shell type and crankset matching requirements.