Nobody knows why your bike has a hollow crank spindle, but it does. Why not make the most of that space and use it to store and work on your bike? The Scorpion is compatible with 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. As with all our products, when not being used it folds in to a compact, portable or stow-able footprint until its needed again.