For minimalist travelers deciding between the Cotopaxi Allpa 35L and 28L, a side-by-side visual comparison reveals the size difference is more significant than the numbers suggest.
A traveler posted images showing both bags loaded with packing cubes, providing exactly the comparison that's frustratingly absent from product pages. The conclusion: the 35L offers roughly 25% more usable volume, not just the 7-liter difference the specifications imply.
This matters because one-bag travelers live and die by capacity optimization. Seven liters might sound modest, but it's the difference between packing for summer only versus including a puffy jacket and long pants for temperature swings.
The comparison showed both bags using Tripped packing cubes—popular in the one-bag community for their durability and compression. In the 28L, users can fit one large cube plus two small cubes comfortably. The 35L accommodates two large cubes plus an additional thin cube, with room left over.
For travelers planning trips spanning multiple climates, that extra space is invaluable. A week in Southeast Asia followed by mountain hiking in Nepal? The 28L requires choosing between destinations when packing. The 35L handles both.
But size isn't everything. The critical question for any carry-on bag: Will airlines accept it?
Most airlines list carry-on maximums around 55cm x 40cm x 20cm (22" x 16" x 8"). The Cotopaxi Allpa 35L measures 55cm x 35cm x 23cm, putting it technically over the depth limit by 3cm. In practice, experienced one-baggers report that gate agents rarely measure bags this precisely unless they're obviously oversized. The Allpa 35L's flexible fabric allows it to compress slightly if needed.
The 28L, measuring 51cm x 33cm x 18cm, stays comfortably within limits across all carriers, including budget airlines known for strict enforcement.
So which should you choose?
The 28L makes sense if you: - Travel primarily to warm climates - Fly frequently on budget carriers with strict size limits - Prioritize absolute peace of mind at gates - Have mastered extreme packing minimalism
