Mont Zero Superlight sleeping bag: Tested

By Mattie Gould May 5, 2023
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Mont’s Zero Superlight aims to keep you warm in the wild. We brave the chilly nights of the NSW alpine region to see if it does the job.

Lightweight sleeping bags are a hiker and bikepacker’s best friend. No matter how far and how hard your trip is, the space and weight savings of choosing a lightweight sleeping bag can be enormous. And when it comes to ultralight materials, the Mont Zero Superlight, part of the Aussie company’s Zero Series sleeping bag range, is top of the class.


The Mont Zero Superlight (SL) is designed for 2-3 season, ultralight adventures, and this sleeping bag is temperature rated to 8 degrees for cold sleepers, 2 degrees for warm sleepers.

When it comes to weight, this full-size bag weighs in at an impressively low 417g – extra impressive considering that it’s filled with 230g of 1000+ loft goose down. Mont manage to keep the weight so low by using the very aptly named Anti-Gravity Nylon, which it claims to be the lightest nylon in the world. The weight is also reduced using a half-zip with an ultralight YKK #3 zip.

Don’t let the Zero’s small packed size deceive you. With 1000+ loft goose down, it packs plenty of punch in the warmth stakes.

Using 1000+ loft goose down not only keeps the warmth rating comparatively high, but it also helps the Mont SL sleeping bag achieve a smaller packed size than if it had used a less lofty down. Vertical torso baffles and a contoured hood also help keep you warm overnight.

In the field

I’ve been using the Mont Zero Superlight sleeping bag for a couple of months now and taken it out on three different bikepacking trips, with varying overnight temperatures (see our guide to bikepacking, here). The small, packed size (roughly 12cm x 26cm) means that finding a spot for the sleeping bag on the bike has been a breeze. I’ve alternated between packing it in a dry bag on my forks and putting it in my handlebar bag.

The Superlight’s Anti-Gravity Nylon allows the down inside to loft to its full potential, ensuring optimum warmth.

Arriving at camp, it’s always a good idea to get your sleeping bag out of its bag as early as possible, to give it plenty of time to puff up and trap air. Giving it a good shake out is also a good idea. The Anti-Gravity Nylon allows the down to loft to its full potential, giving a visibly puffed-up look to the sleeping bag.

The half-zip affords ample room to climb into the sleeping bag, and there’s a stretchy pull cord to cinch the entry closed even more, as required. I consider myself a cold sleeper, and I’ve used the Zero SL sleeping bag in conditions ranging from 0 degrees to 8 degrees. On the colder night, I was also using the Mont Thermolite sleeping bag liner, which I was thankful for. 

The final word on the Mont Zero Superlight

The Mont Zero Superlight Sleeping Bag is comparatively priced to its competitors and reflects the quality of materials used. It’s proved to be an excellent spring and summer sleeping bag for the changeable conditions of the lower alpine regions I’ve been testing it in and I’m looking forward to using it as an ‘extender’ over the colder months.

RRP: $549.95 See Mont for more info on the Zero Superlight and the brand’s full range of outdoor gear.