Old Man Mountain 12L Atlas Rack Pack Review

I’m the first to tell folks that a standard dry bag makes the perfect rack-top bag. They are affordable, available in all sizes, and easy to find, with single- or double-ended roll-tops. For anyone on a budget or just starting out, any old dry bag on any old rack can serve as the perfect foundation for a bikepacking setup. I try to practice what I preach, but I’ve had the chance to test some dedicated bags designed for the top platform on a rear rack, and they work great, too.

It wasn’t so long ago that there weren’t many options, but this is changing quickly. Now, brands like Rockgeist, Ortlieb, Dispersed, South City Stitchworks, and others offer improved versions of a standard dry bag. They boast advanced attachment systems, exterior pockets, bungees, and shapes tailored for use on a rear rack. They’re all good at what they do, but there’s still room for further innovation in this segment of rack-top bags.

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Last winter, Old Man Mountain released the first Atlas Rack Pack in tandem with its Hemlock Fork Pack and FLiP Cages. The first Atlas Rack Pack had a 9L capacity, waterproof construction, and a bungee lace-up on top. Although Logan thinks it looks like a sandcrawler from Star Wars, its slanted front end is designed to provide more clearance for dropper posts, which can be an annoyance on small frames and for folks running long dropper posts. The new 12L Atlas Rack Pack shares many of the same specs and features, including a welded, waterproof TPU construction, Hypalon reinforcements on the sides and bottom, and four webbing straps with cam-lock buckles to secure it to your rack. The main differences are an additional three liters of capacity, small zippered side pockets on both sides of the bag, and an air-purge valve at the front.

The new 12L Atlas Rack Pack also has a slight taper at the slanted end, which isn’t part of the 9L design. This means a lower chance of it rubbing your leg while pedaling or getting in the way when the saddle is dropped, and the bike is leaned into corners. Looking at the comparison chart below, we can see the 12L Atlas Rack Pack is 6″ tall (0.5″ taller than the 9L bag), 6.3″ wide, and around 15.3″ long with the opening rolled up. It might not be big enough for winter bikepacking, but it’s a large bag. The dimensions look and feel right: it’s not too long on a rack and doesn’t sit too high, so it doesn’t feel awkward or wobbly.

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Having mostly used rack bags without structured shapes, it didn’t take long to see the value of the Atlas Rack Pack’s slanted nose. I’ve gotten used to just compressing my rack bags with my post dropped, which is surprisingly effective, but being able to use all your dropper post travel without any bag contact feels downright luxurious. Despite a somewhat basic webbing attachment system, it’s easy to quickly loop the webbing around the rack rails and lock them into the buckles. It’s quick enough that I’d be fine removing the bag at camp, as long as I didn’t have any panniers in the way, making the process awkward. When attached and cinched in place, the Atlas Rack Pack has minimal movement, if any.

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Based on the photos, the Atlas Rack Pack works best on a rack with a top platform parallel to the ground. Depending on the rack and bike, some racks tilt downward toward the seat tube, which does not work well with the Atlas Rack Pack. Emily’s medium Esker Japhy and Mica Rat Tail combination didn’t work well with the bag, with the saddle positioned directly on top and the slanted portion tucked underneath. At 15.3″ long when rolled closed, and over 6″ wide, it’s most stable when paired with a large rack platform.

The addition of side pockets is thoughtful and functional for quick-access items. I appreciated the pockets on the Ride Forward Designs rack bags I tested, and liked having two oversized stretchy pockets on the larger version. Old Man Mountain’s pockets are small and capacity-limited, but the secure zippered opening and drain holes are nice touches. I would have loved to see larger, stretchy pockets on both sides. Given the bag’s capacity and heavy-duty waterproof construction, adding an air-purge valve seems logical, especially when stuffing bulky sleeping bags and layers inside. Like most saddle packs, the tapered nose requires some extra attention while packing, and it’s best to stuff in a few smaller items first to make the most of the bag’s capacity.

I’ve been working on a list of rack bags, and the 12L Atlas Rack Pack is the heaviest so far. At 360 grams (12.6 ounces), it’s over 100 grams heavier than the 11L Ride Forward Designs bag and the 12L North Street Bags Top Trunk Bag. There are also several options under 300 grams, with a little less capacity, but the Atlas Rack Pack is one of only a few that can claim full waterproof status. It’s a burly, well-designed bag, and I’m looking forward to seeing how the growing rack-top bag segment evolves from here.

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• Capacity: 12L
• Material: TPU / Hypalon
• Weight: 360 grams
• Place of Manufacture: TBD
• Price: $125 USD
• Manufacturer’s Details: OldManMountain.com

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