So a saddle bag for road bike is the little (though sometimes quite large) sack that dangles beneath your saddle, generally attached to the seat post. Frowned on by cycling purists, who point to the perfectly adequate set of pockets on the back of your jersey, you generally use your saddle bag to store a spare inner tube, tyre levers, a multi-tool. If you’re in the market for a new waterproof bicycle saddle bag then you we can all purchase together, creating a strange demand spike for under seat storage that will have retail analysts a-guessing and a-theorising. Actually, on that point, some of the links in this post are affiliate links. If you click through and buy , I might get a small cut (depending on the vagaries of their record-keeping systems). You’ll pay exactly the same price. If you do reward me in this way, you get the warm karmic glow (perhaps in your dangle sack) that you’re helping support the site and the costs associated with it.