Which axle do you need?All Switch Racks come with an axle supplied. This is designed to replace the one current axle. It is compatible with 142mm and 148mm (boost) spacing and comes supplied with spacers to tune fit. It is imperative to use the correct thread pitch for your frameTo determine the correct thread pitch, remove your current axle. Many have the thread pitch printed on the axle. It will be either 1mm, 1.5mm or 1.75mmIf it is not printed on the axle, you will need a ruler. Count our ten threads from the end of the axle and measure the distance. If it is 1cm, you have a 1mm thread pitch. 1.5cm = 1.5mm thread pitch, 1.75cm = 1.75mm. If you are still unsure, check with your frame manufacturer directly. Fitting the Switch axle:Remove your bikes current thru-axleFit the Restrap Switch thru-axle using a 6mm allen key. Use as many 3mm washers as necessary to centralise the top bar over the rear wheelUse the supplied axle cone spacer for compatible frames Features:High Grade 7075-T6