Water resistance vs. waterproofness

Water-resistant vs. Waterproof. What's the difference and why is it important when choosing a bag?

These two words sound similar and are often used interchangeably, but they mean something entirely different. If you've ever returned from a trip with a wet phone despite a "waterproof" bag, this article is for you.

Water-resistant is not waterproof

Water-resistant means that the material effectively repels water, but it is not completely impervious to it. Imagine a rain jacket that handles drizzle and moderate rain well, but after several hours of heavy downpour, it starts to let moisture through. It's not broken. It's just doing what it was designed to do.

Waterproof, on the other hand, is a completely different level. A waterproof material does not let water through at all, even under pressure, even after a long time. This property is reserved for products such as diving suits, specialized electronics cases, or dry bags used in kayaking.

What does this have to do with fabrics?

Both X-Pac® and Cordura are water-resistant materials, not waterproof. They are coated with DWR (Durable Water Repellent), which makes water bead up and roll off the surface instead of soaking into the fabric. It sounds good and actually works well, but this is a property of the material itself, not the finished bag.

Because here's the crucial point: stitching.

Every seam is a potential point of water ingress

A needle piercing the fabric leaves holes. Even if the material itself repels water, the seams remain a weak point in the entire construction. In equipment requiring full waterproofing, seams are additionally sealed with special tape or glue — this is how expedition tents or kayak bags are made.

But truly waterproof bags are primarily welded, not sewn products. Instead of needle and thread, layers of material are joined thermally or chemically, without any holes. This is a completely different technology and a completely different product.

Due to their nature, bikepacking bags simply cannot be welded. They have relatively small sizes, specific shapes adapted to the frame or handlebars, and are heavily stiffened to maintain their form under load. Sealing the seams with specialized tape in such a construction would be extremely difficult even with professional machines, and welding would completely change the properties of the finished product. This is a conscious design choice, not a cost-saving measure.

Breathability as an advantage

There's another thing that's rarely talked about. Bikepacking bags are not airtight, and this is not a flaw. A material that breathes allows moisture to escape. In practice, this means that a damp jacket or sweaty clothing packed after exercise won't rot and smell when sealed in an airtight compartment. Air microcirculation is something you won't find in a fully waterproof bag.

What does this mean in practice?

A bag made of X-Pac® or Cordura will handle rain, splashes, and typical trail weather just fine. In intense, prolonged downpours, water might get in through the seams. The solution is simple: zip-lock bags and dry bags for items that cannot get wet. Electronics, documents, spare clothing layers, each separately, each protected.

Besides, most experienced cyclists pack this way anyway. No one carries dirty clothes with clean ones, a wet protector with sandwiches, or a phone loosely at the bottom of the bag. Dividing items into bags is simply good organization, no matter what bag you have.

Why are we even writing about this?

Because we prefer you to know what you're buying. Many brands prematurely claim "waterproof" and hope no one will ask. We prefer an honest blog post over a disappointed customer on the trail.

X-Pac® is an exceptional material. Our bags are durable, weather-resistant, and look great after years of use. But they don't go underwater. And that's perfectly fine.