This ultralight fastpack became my favourite trail running bag (and it’s not even waterproof)

Only recently discovered Gossamer Gear, and I’m kicking myself for missing out on the brand’s ultralight bags for all these years. Based on my recent experience with the Grit 28L Fastpack, which I used for everything from off-road marathons to hikes and beyond, the company is not to be missed if you’re keen on travelling light on your feet.

As the name suggests, the bag I’m reviewing here is a 28-litre backpack specifically designed for trail running and fastpacking. It’s somewhat of a cross-breed between hiking and running backpacks (specifically running vests), with some cycling backpack features (e.g. rolltop closure) thrown in for good measure.

I love the bag; it became my favourite backpack for off-road adventures. From the perfectly-padded shoulder straps to the well-thought-out pockets, the Grit 28L really is a trail running backpack that keeps giving. Apart from very short distance running, the backpack is suitable for all manner of outdoor activities, thanks to its expandable nature and excellent weight distribution.

Gossamer Grit 28L Fastpack review

Price and availability

The Gossamer Grit 28L Fastpack was launched in March 2025 and is available to buy now directly from Gossamer Gear for the recommended price of $180 (~ £133.07/ AU$ 275.72). It comes in one size (28 litres) and one colour. The bag is shipped for free within the us; international shipping is calculated at checkout.

Specifications

• Best for: Trail running and fastpacking
• Weight: 16.2 oz/ 459 g
• Capacity: up to 28 litres
• Waterproof: No

Design and materials

The Grit 28L is made with 100D recycled Robic nylon and UHMWPE stretch mesh, a combination of sustainable materials that ensure the bag stays durable and lightweight. At 459 g, it weighs less than a small bag of sugar, even with the removable back panel in place.

One of the showstopper features of the Grit 28L is how well it allows you to organise your pack. The backpack has a rolltop closure, which helps keep the size of the main compartment to a minimum while also allowing some flexibility.

You’ll find two large water bottle pouches on the side and a decent-sized, zippered pocket above a quick-access large mesh pocket on the front of the bag (perfect for storing waterproof jackets or fleeces).

Flip the bag over to access the vest-style harness with double sternum straps – these can be moved vertically to better adjust to your body shape. Both shoulder pads have multiple pockets for collapsible water bottles, smartphones, snacks, etc. The pads themselves are incredibly ergonomic; I experienced no rubbing or chafing even with the bag full.

Multiple attachment points are scattered around the bag’s exterior, making it suitable for carrying walking sticks, ice picks, or whatever else you carry.

It’s worth noting that, like in the case of other adjustable bags (see also my article on the excellent Matador Freerain28), the Grit 28L has a bunch of loose cables and straps everywhere. The price you pay for adjustability!

Performance and comfort

I have taken the Gossamer Grit 28L on many trips since receiving it in April. One of my first outings was a trail marathon with minimal support along the route, which provided an excellent opportunity to see how well the backpack holds up in more challenging conditions.

I filled it with water, snacks, an emergency kit, spare layers and my trusty Leki Ultratrail FX.One poles (retailer link). It was a turbulent day, not least because I didn’t do enough training prior to the event. It might have been a slog for me, but the Grit 28L completed the task with flying colours!

I particularly enjoyed the harness and its many pockets. They are perfectly placed and let you store a ton of essentials in a place that can be accessed without removing the backpack (and, therefore, slowing you down). To a certain extent, the Grit 28L is like a running vest with an oversized main compartment.

However, calling it that would grossly oversimplify what the bag has to offer. For one, it can be used for hiking, too, and not just trail running. The main compartment is big enough to house a two or 3-person backpacking tent, a 2-season lightweight sleeping bag and a camping mat. How many running backpacks can claim that?!

The shallow rectangular shape and the sternum straps make the Grit 28L sit perfectly on your back. I haven’t tried the bag without the back panel, but it’s easy to remove if you’re really keen on reducing weight. It doesn’t weigh much – 61g according to my kitchen scales – but I appreciate it’s more than nothing, especially for those into their UL setups.

The Grit 28L is not only an excellent running companion but also perfect for slower movers (a.k.a. hikers). I took it on many trips over the last two months, and I can’t say I regretted choosing it over other bags I have. The bag’s size almost makes more sense hiking; it’s big enough to store layers, snacks, and water for two people.

Verdict

The Gossamer Grit 28L Fastpack is a near-perfect hybrid of a trail running vest and a lightweight hiking pack, offering just the right blend of comfort, function, and fast-moving performance.

The vest-style harness is among the best I’ve tested: secure, breathable, and equipped with more storage than your average daypack. The rolltop design and modular layout offer fantastic flexibility from racing a self-supported ultra to fastpacking in the hills.

It’s not waterproof, and the abundance of dangling loops and cords can feel fiddly, but that’s the trade-off for true adjustability. And while it may be overkill for short runs, it excels at anything longer or more gear-intensive.

The Grit 28L proves that ultralight gear doesn’t have to be bare-bones. If you want a fastpack that disappears on your back but always delivers, this is the one.