Expandable, watertight, and race-tested—Tailfin’s modular rackbag gets a smart redesign
The Tailfin AeroPack Cargo (also called the AP18 Cargo) is the latest evolution of Tailfin’s class-leading bikepacking trunk system. Combining the company’s distinctive Arch + Bag design with expanded exterior storage, a simplified single-strap closure, and a redesigned roll-top system, the Cargo builds on the success of the original AeroPack while addressing real-world rider feedback.
Like its predecessor, the Cargo version mounts either to a Tailfin Carbon or Alloy Rack (or directly using Tailfin’s quick-release dropout hardware), forming a secure, lightweight, and fully integrated rear carrying system. But with new side mesh pockets, a lighter closure, improved ergonomics for dropper post clearance, and a bright interior lining, the AP18 Cargo is now more functional and versatile than ever.
If you’re hunting for a waterproof bikepacking trunk bag that stays rock-solid on technical trails, fits a minimalist setup, and remains easy to load, this upgraded AeroPack may be your perfect match.
Key Specifications
| Feature | Tailfin AeroPack Cargo (AP18) |
|---|---|
| Bag Weight | 573g (without hardware) |
| Capacity (Main) | 18L (expandable roll-top) |
| Cargo Pockets | 2 expandable side mesh pouches (~3L total) |
| Attachment | Compatible with Tailfin AeroPack frame or AP racks |
| Material | Welded Hypalon and ripstop nylon |
| Closure | Single central compression strap with roll-top |
| Valve | Integrated air purge valve |
| Light Mount | Rear-facing mount and light slots |
| Accessory Mounts | Underside cage mounts (64mm spacing) |
| Water Resistance | Waterproof construction |
| Price | £150.00 (bag only), £326.00 with mount hardware |
What’s New: Key Differences from the Original AeroPack
Tailfin’s original AeroPack established a new class of bikepacking gear: the trunk bag that behaves like a pannier-less rack setup. It was waterproof, rigid, and dropper-friendly—but it wasn’t without limitations.
The Cargo version (AP18) brings meaningful upgrades that make packing faster and access easier:
Expandable Mesh Pockets
- Stretch mesh side pouches add ~3L of usable space
- Ideal for stashing jackets, tripods, snacks, gloves
- Fold-over design helps prevent items from bouncing out
Central Roll-Top + Single Strap Closure
- Simplifies packing: no front/rear buckles to fumble with
- Results in a cleaner profile and more efficient compression
- Single TPU-reinforced strap secures both main bag and pockets
Integrated Purge Valve
- Allows air to escape for tight packing
- More effective than side zippers used on the original
Bright Interior Liner
- Contrasting interior makes it easier to find small items
- Fixes a common nitpick with the all-black original version
Underside Accessory Mounts
- 64mm-standard bolt spacing
- Compatible with cargo cages or extra bottle mounts
These changes make the AeroPack Cargo easier to live with day to day, especially for riders who are packing or unpacking on the move, racing ultra-events, or riding in mixed weather.
Real-World Use: First Rides & Technical Observations
We tested the Tailfin AP18 Cargo on gravel roads, wet Scottish singletrack, and a multi-day off-road loop in Snowdonia. The test rig used Tailfin’s standard Carbon AeroPack Arch with pannier mounts (though panniers weren’t used for this setup).
Here’s what stood out in use:
Mounting & Setup
Installation took less than five minutes using the pre-mounted hardware from an older AeroPack setup. The bag attaches at two points:
- Rear bolts connect to the AeroPack Arch
- Front mounting straps cinch around the seatpost or seat tube
The Cargo bag is cross-compatible with any Tailfin AP system, so if you already own a Tailfin rack or original AeroPack, you can slot this right in.
Stability Under Load
Tailfin’s hallmark is zero sway—and the AP18 Cargo keeps this reputation intact. Descending chunky double track or bunnyhopping potholes, the load remained rock solid. The carbon support rods on the side panels prevent bulging or distortion, even when fully packed.
Dropper Post Compatibility
The redesigned closure pulls tension toward the center, slightly improving seatpost clearance. That translates to a few extra millimeters of drop when using a slammed dropper—subtle, but welcome. It doesn’t fully solve the “butt contact” issue for aggressive riders on steep gradients, but it helps.
Access & On-the-Fly Adjustments
The new single strap system is faster and more intuitive than the original two-strap version. It tightens uniformly over the main roll-top and across both cargo pouches. Pull, cinch, go. The side pouches are game-changers for convenience: no more digging through a sealed drybag to grab gloves or a headlamp mid-ride.
Waterproofing & Abrasion Resistance
Three rainstorms and several muddy trail sections later, the AeroPack Cargo’s interior remained dry. The welded Hypalon/Nylon construction holds up well to scrapes and wall-leaning, with no signs of abrasion or mesh sag. The water purge valve works great to compress contents after rolling the top shut.
Cargo Pocket Use Tips
The standout feature—those stretchy cargo pouches—are surprisingly generous. Use cases during testing included:
The clever folded rim design helps seal in contents without zippers or velcro, reducing the chance of lost items on rough descents. Ultra-racers in Tailfin’s R&D group reportedly use the side pouches to cut down on stop time during races, storing fast-access calories and layers without unrolling the main compartment.
If you’re running Tailfin 16L mini panniers, note that bulging cargo pockets may slightly interfere with the side clamping levers. It’s manageable but something to be aware of with full setups.
Fit, Flexibility & Modularity
One of the main benefits of the AeroPack system is modularity. With the Cargo bag, you can:
- Use it as a standalone rear storage solution
- Pair it with Mini Panniers for ~50L total capacity
- Mount an underside bottle cage or tool roll
- Detach the whole unit in seconds with the Quick Release dropout option
We’d still love to see shorter arch versions in the future for smaller frames or riders under 5’7″, as clearance over the rear wheel can be tight with dropper use. That said, the AP18 Cargo is currently one of the most secure, dropper-compatible rear bags on the market.
AeroPack Cargo vs AeroPack Original
| Feature | Cargo (AP18) | Original AeroPack |
|---|---|---|
| Main Capacity | 18L | 20L |
| Side Pockets | ✅ Yes | ❌ No |
| Closure | Single center strap | Dual front/back straps |
| Access Speed | Faster | Slower |
| Air Valve | ✅ Yes | ❌ No (old version had side zip) |
| Waterproofing | Excellent | Excellent |
| Best For | Modularity, speed | Simplicity, maximum volume |
| Price (USD) | £326.00 – £442.00 | £296.00 – £412.00 |
In summary, the AP18 Cargo is easier to use, more flexible, and better suited for modern bikepacking needs than the original AeroPack—especially if you value quick access and modularity.
Pros and Cons
Pros
- ✔️ Secure and sway-free, even on technical terrain
- ✔️ Side cargo pockets add ~3L of fast-access capacity
- ✔️ Simpler closure system with improved ergonomics
- ✔️ Fully waterproof and dropper-friendly
- ✔️ Excellent build quality and clean aesthetics
- ✔️ Compatible with any existing Tailfin AeroPack setup
Cons
- ❌ Still pricey compared to basic drybags
- ❌ Frame arch remains tall—dropper overlap possible
- ❌ Side pockets may interfere with pannier clamps when overstuffed
- ❌ Not compatible with
Who Should Buy the AeroPack Cargo?
The AP18 Cargo is purpose-built for:
- Bikepackers who want a fully waterproof, pannier-free rear load system that won’t sway over rough terrain
- Riders using dropper posts, full-suspension MTBs, or gravel bikes where traditional racks don’t fit
- Minimalist tourers and ultra-distance racers looking for secure, quick-access cargo storage
- Commuters and weekenders who prioritise waterproof gear with modular capacity
If you already use Tailfin’s AeroPack system, the Cargo upgrade is a logical next step—especially if your current setup lacks easy-access storage or feels bulky. And if you’re entering the system from scratch, the Cargo paired with Tailfin’s Carbon or Alloy Arch + Quick Release hardware delivers a no-rattle, race-ready solution that just works.
Accessories & Add-Ons Worth Considering
Tailfin’s ecosystem is thoughtfully designed, and pairing the AP18 Cargo with a few extras makes it even more capable:
| Accessory | Why Add It |
|---|---|
| Mini Panniers (5–10L) | For additional secure side storage |
| Carbon Rack Frame | Lighter, sleeker than the alloy option |
| Cage Mounts (underbag) | Carry bottle, tool keg, or drybag below |
| Pannier Adapters | Enable standard pannier compatibility |
| Top Tube/Frame Bags | Expand carrying without bulk |
Every component integrates cleanly, allowing full customization without Velcro chaos or zip tie hacks.
Final Verdict: Is the Tailfin AeroPack Cargo Worth It?
Absolutely. The Tailfin AeroPack Cargo is more than a rack-top bag—it’s a refined storage system that bridges the gap between ultralight minimalism and rack stability. With the AP18 update, Tailfin has improved on its already standout product with smarter storage, better ergonomics, and added versatility.
It’s not cheap—but if you value weather protection, modular upgrades, and rock-solid performance, there’s really nothing quite like it on the market.
