Aluminumalloy barrel shaft adapter for converting 15mm barrel shafts to 12mm mini barrel shafts. Designed for use with common 100×12mm road disc brake hubs. Key benefits Saves money: lets you keep existing hubs when upgrading forks or switching axle standards instead of buying hubs. Lightweight and strong: made from aluminum alloy to minimize added weight while maintaining strength and durability. Precise and stable fit: conversion seat design improves hub alignment and stability after installation. Broad compatibility: fits common 100×12mm road disc brake hubs on the market, maintaining original hub function. What it does Converts a 15mm barrel shaft to a 12mm mini barrel shaft so your 100×12mm road disc brake hub can be used without replacing the hub body. Maintains accurate hub positioning and reliable performance once installed, reducing the need for further adjustments. Specifications and attributes Material: Aluminum alloy Conversion: 15mm barrel shaft → 12mm mini barrel shaft Compatible with: common 100×12mm road disc brake hubs Design: Conversion seat for improved accuracy and stability Use scenarios Upgrading forks: If you upgrade to a fork that uses a 12mm thruaxle, this adapter lets you retain your existing 100×12mm road disc brake hub without replacing it. Using wheels across bikes: Move wheels between a bike with a 15mm axle and a bike requiring a 12mm mini barrel shaft without a hub swap. Costconscious repairs: Restore compatibility after a fork or axle change without buying a hub assembly, saving time and expense. Materials and performance notes Aluminum alloy construction balances low weight and strength for reliable everyday use. Conversion seat design increases installation accuracy and helps maintain hub stability under riding loads. Designed for compatibility and stability while minimizing cost and component replacements.