The Topeak Zi:RAK Thru-Axle 12 x 1.75mm (Art No. TA2420-SP03) is a precision-engineered rear axle designed for mounting the Topeak Zi:RAK rear rack on compatible 700C road and gravel bikes. Built from high-strength aluminum alloy, it provides reliable stability while keeping weight to a minimum. Featuring a 12mm diameter, 1.75mm thread pitch, and 170mm axle length, it includes multiple spacers for fine-tuned fitment across different frame standards. The 20mm thread section ensures a secure and vibration-free installation—perfect for touring, commuting, and endurance riding.