Discover the ultimate solution for precise drivetrain tuning with Wheels Manufacturings high-quality Freewheel and Bottom Bracket Cup Shims. Designed to enhance bike performance through fine adjustments, these spacers are essential for cyclists and bike mechanics aiming to perfect chainline alignment and crank clearance on bikes with B.S.A external bottom bracket cups. Crafted from durable materials like corrosion-resistant aluminum or high-strength composites, these shims ensure reliable performance and longevity even under demanding riding conditions. Engineered with precision manufacturing techniques, each shim offers consistent thickness options1.0mm, 1.5mm, and 2mmto accommodate a variety of frame and component setups. Their innovative fit between the frame and drive-side cup allows for seamless, hassle-free installation, enabling riders to fine-tune their freewheel or cassette positioning for optimized shifting, drivetrain efficiency, and component clearance. These spacers are ideal for bike builders seeking to improve chainline or address frame-specific compatibility issues, making them perfect for road, mountain, or hybrid bikes. Enhance your bikes performance and ensure smooth, reliable operation with these precision-engineered cup shims from Wheels Manufacturingan industry leader in bicycle component innovation, quality, and engineering excellence. Whether for professional tuning or personal bike maintenance, these versatile spacers are a must-have for achieving the perfect fit and maximizing cycling efficiency.