You might not carry a lot in your saddle bag, but I imagine that whatever you do carry you would like to keep dry. I ride in all weather conditions and that means I spend more than my fair share of time cycling in the rain. Most seat bags will keep their contents dry during a light shower, but very few bags are really waterproof. A few months ago I put a Topeak Wedge DryBag waterproof saddle bag on the bike I use to ride in the rain and my opinion of this bag can be summed up in one word: Awesome!
The Topeak Wedge DryBag is constructed from 210 denier and 420 denier nylon waterproof fabric and has sonically welded seams to keep the rain out. Not only does this bag keep the rain out, but it is incredibly easy to clean up. I sometimes ride off-road trails during rainstorms and the knobby tires on my mountain bikes kick up a lot of mud. Washing muddy clothes is pretty easy (I have a great wife), but getting the mud off most saddle bags is nearly impossible. If your Topeak Wedge DryBag gets muddy you can clean it off with a water hose as you are rinsing off your bike (you don’t even have to take it off your bike).
The zippers on most seat bags allow water to seep into your bag and they also get clogged up by mud. Instead of zippers the Topeak Wedge DryBag uses a roll closure with a Velcro strip, and after the flaps are rolled up the bag is secured with a buckle on both sides. Topeak offers this bag with two different mounting styles: nylon straps that wrap around your seat rails or Topeak’s QuickClick™ System that makes it easier to attach or remove the bag. The rear flap on the bag has a clip so you can attach your favorite taillight.
The DryBag comes in three different sizes. The smallest bag has a 36 cubic inch (.6 L) storage capacity; the medium bag has 61 ci (1 L) capacity; the large bag has 91.5 ci (1.5 L) of interior space.
The Topeak Wedge DryBag is available at most bicycle shops and retails for between $40 to $50, depending on the size and mounting style. This product also comes with a limited 2-year warranty against manufacturer defects (keep your receipt).