Bike trainer thru-axle adapter designed to convert bikes with a thru-axle rear end for secure use on most indoor trainers. Key benefits Secure, accurate fit: CNC-machined aluminum alloy provides consistent tolerances for a snug, stable connection between your bike and trainer, reducing side-to-side play during hard efforts. Durable and lightweight: Aluminum alloy construction balances strength and low weight so the adapter withstands repeated indoor use without adding unnecessary mass. Simple length adjustment: Two-piece design lets you quickly set the axle to the correct span (142 mm to 148 mm) for common thru-axle road and gravel rear ends. Extends bike use year-round: Use your outdoor bike indoors throughout winter or bad weather, maintaining training continuity without swapping wheels. What makes it stand out Precision CNC machining for repeatable alignment and reliable engagement with trainer mounts. Broad compatibility with most indoor bike trainers that accept thru-axles—no custom parts needed for typical setups. Adjustable 142–148 mm range covers the most common rear thru-axle standards used on road, gravel, and many hybrid bikes. Features Material: Aluminum alloy for strength and corrosion resistance. Manufacturing: CNC-machined for high accuracy. Design: Two-piece shaft for easy length adjustment and secure installation. Length range: Adjustable from 142 mm to 148 mm to match common thru-axle spacings. Function: Converts bike rear thru-axle to fit indoor trainers, enabling stationary use. Typical use scenarios Winter training: Mount your bike on a trainer for structured indoor workouts and virtual rides when roads are unsafe or weather prevents outdoor riding. Virtual group rides and races: Securely connect your bicycle to a smart trainer for Zwift, TrainerRoad, or similar platforms without changing wheels. Bike setup and maintenance: Hold the rear wheel in a stable position on a trainer to check drivetrain adjustments or test gear changes indoors. What you get A CNC-machined aluminum thru-axle trainer shaft with two-piece adjustable design (142–148 mm), compatible with most indoor trainers that accept thru-axles. Notes Designed specifically for use with indoor bike trainers and thru-axle-equipped rear ends. Confirm your trainer accepts thru-axles and that your bike’s rear spacing falls within the 142–148 mm range before purchase.