Instead of stepping up the size of your hydration pack, use the Lezyne XL Caddy Saddle Bag to hold your extra gear without adding weight to your back. Its streamlined design stays out of your way and sits neatly under your seat without using a strap on the seat post--meaning droppers aren't an issue. The zipper opens extra-wide for easy access to all of your gear while maintaining a super-secure closure so nothing is lost regardless of if you're riding pavement or dirt.