Zipper Cosinus – Your Frame, Your Rules. Tailor-Made Perfection.
Standard bags leave gaps. The Zipper Cosinus fills them. Designed for bikepackers who refuse to compromise, this bag is custom-sewn to fit the specific geometry of your bicycle frame down to the last millimeter.
Why settle for “universal” sizes when you can have a bag that utilizes 100% of your main triangle’s potential? Whether you ride a gravel bike, a hardtail, or a road machine, the Cosinus adapts to you.
📐 The Two-Chamber Advantage: Organize & Slim Down
The Zipper Cosinus isn’t just a sack; it’s a smart organizer. We have equipped it with a horizontal partition (placed at approx. 2/3 of the height) that divides the bag into two chambers.
- No Bulging: The internal divider acts as a structural rib, preventing the bag from “ballooning” outward when packed full. This means your knees won’t rub against the bag while pedaling.
- Smart Access: Keep heavy items in the lower chamber and frequently used gear in the upper one.
- Total Flexibility: Need to carry long tent poles? The partition is attached with Velcro. You can detach it completely or just partially to slide long items vertically through the bag.
🔒 Rock-Solid Mounting
A frame bag should be one with the bike. We use a continuous loop system along the entire edge of the bag, allowing you to place the mounting straps exactly where your frame allows it (avoiding cable stops or bottle bosses).
The set includes eight mounting straps lined with a special non-slip material. This protects your frame and ensures the bag doesn’t shift, even on rough terrain.
🛡️ Cordura® TPU: Tough & Splash-Proof
Built from our legendary Cordura® TPU, the Zipper Cosinus is incredibly resistant to abrasion and tearing. The thick internal TPU coating ensures the fabric itself is waterproof.
Important Note on Water Resistance: Unlike our Dry series, this bag is constructed using a sewing process. While the fabric is waterproof and the zipper is splash-proof, the seams are not sealed. The bag will withstand moisture and moderate rain, but it is not designed for full submersion. We recommend packing sensitive electronics in a dry bag inside.
🎒 Pocket Organization
We know you need quick access to essentials. The Cosinus features:
✅ Internal Pocket: Located just below the main zipper for keys, wallet, or documents – see the main gallery above.
✅ External Mesh Pocket: Located on the non-drive side. Perfect for stashing energy bars, gels, or wrappers on the go.
⚠️ Important Ordering Information
🛑 Custom Product: Since this bag is made-to-measure specifically for your frame, returns are not accepted. Please measure carefully!
📏 Production Tolerance: +/- 3% in dimensions.
🛡️ Frame Protection: Even with our non-slip straps, long-term vibration and grit can dull your bike’s paint. We highly recommend applying protective tape or foil to your frame before mounting any bikepacking bags.
📏 Order Now, Measure Later!
Don’t worry about technical details at checkout. Simply place your order today, and we will send you a separate email with easy-to-follow instructions on how to provide your frame’s dimensions.
We will guide you through every step to ensure your custom bag fits perfectly!
Ready to maximize your storage? Order your custom Zipper Cosinus today.
