The Scorpion is compatible with 10, 13, 18 and 20mm hollow crank spindles on either side of the bike. The design elevates the rear wheel and lends itself to lite bike maintenance, like chain lubrication and frame cleaning. When not being used it can be disassembled to a flat, compact, portable or stow-able footprint until it’s needed again. Please check your hollow axles for compatability before buying.