As its name suggests, the Rab Ascendor 45:50L is built for the mountains, but does the performance match the title? And can this pack make it into our list of the bestmountaineering backpacks?
Though better known for its technical apparel and sleeping bags, British brand Rab has plenty of heritage when it comes to pack design, largely handed over from sister brand Lowe Alpine.
A couple of years back, the two manufacturers decided to refocus their backpack and rucksack lines.
Lowe Alpine would concentrate on the hiking, trekking, backpacking and travel sectors, while Rab took over in categories such as trail running, fast hiking, mountaineering and climbing, as well as offering a capsule range of all-round daypacks.
LFTOwww.alpinetrek.co.uk
Pros
- Tough and weatherproof
- Good volume-to-weight ratio
- Comfortable to carry (if it fits)
- Secondary access to main compartment
Cons
- One size only, no women’s version
| RRP: | £150 / $185 |
| Weight: | 1.34kg / 12 lb 15 oz |
| Volumes: | 45+5L |
| Materials: | Main Fabric: 35% Recycled 210 ROBIC DIA R/S / Trishield Dura and 50% recycled 420D Mesh Dobby / Hydroshield |
| Sizes: | o/s (unisex) |
Summary
The Ascendor 45:50 is made with technical pursuits in mind, but has the versatility to handle anything from mixed winter climbing to ski mountaineering.
It’s a big pack, with five litres of expanding capacity enabling you to carry up to 50 litres in total. For me, this is pretty much the perfect size for winter adventures, occupying the upper end of that 40-to-50 litre ‘sweet spot’.
However, it isn’t bulky, with a streamlined and stable design. This makes it well-suited to climbing and scrambling.
It has the ability to stow ice axes, trad climbing gear and a rope for more technical use, as well as an A-frame ski carry option for ski-mo.
But other features like a floating lid, hydration compatibility and zippered side entry access to the main compartment all make it a good choice for winter hillwalkers, too. We took it Munro-bagging in Scotland in February to see how it fared…
Design and features
The Ascendor 45:50L is a slim and sleek pack, despite its large volume. It’s basically a modern adaptation of the classic tall, narrow ‘Alpine’ design, with a tapered profile that widens at the top. This makes for much easier loading and rummaging compared to packs with a more traditional shape.
It can swallow plenty of kit, aided by a double drawcord collar with a ‘widemouth’ opening. This is covered by a floating lid that closes with a sturdy single metal buckle.
When cinched in, the angled drawcord collar folds over for a more protective seal. This is intentional, since the lid of the pack can be completely removed if you don’t need it or want to save weight.
A stiffened triangular flap with a stitched webbing strap can also be used to carry a rope or employed as top compression.
The buckle of this strap tucks neatly away via a secondary webbing loop on the underside of the lid, so it doesn’t get in the way – a nice design feature that is a shortcoming with many other mountain packs.
In addition to the top-loading design, the pack has secondary access to the main compartment via a chunky side zip, which is protected by a small storm flap. This is far more user-friendly than having to unbuckle the lid and undo the drawcords every time you want to get inside.
Each side of the pack is fitted with two adjustable side webbing straps. The topmost straps have side-release buckles, which means they can be used as compression or to stow extra gear.
The front panel has extended daisy chain webbing, with elastic bungees for securing trekking poles or ice axes.
Meanwhile, two aluminium ‘headlocker’ attachments on elastic cords are positioned at the base, providing secure lashing points for ice axes, with a central pick guard for added safety.
Harness and back system
The Ascendor 45:50 is marketed as a unisex pack, and the 18” (46cm) fixed back length should work for a variety of users. It’s a shame there’s no dedicated women’s version, though, or at least a couple of different torso sizes available, which would help fine-tune the fit.
Shoulder straps are malleable and softly padded. They’re fitted with load lifters and a chest strap (with integrated safety whistle).
The hip fins are nicely contoured but can be removed if required, so as not to obstruct a climbing harness. Both fins have webbing gear loops for clipping trad gear or ice screws.
The moulded back panel is simple but effective, with a central channel and a curved profile, designed to follow the natural curvature of the spine and provide some lumbar support. It sheds snow well and doesn’t absorb too much moisture.
Internal framing consists of a rigid plastic framesheet and a perimeter wire, which provides plenty of support even for heavier loads.
Pockets and storage
The roomy main compartment swallows plenty of gear and, as said up top, its tapered shape and wide opening makes for easy loading and rummaging, as does the side entry zip.
The main compartment has a hydration sleeve and a central exit port enables you to thread a drinking tube through to either shoulder.
Additional storage comes from two lid pockets. The outside lid pocket is big enough to stash winter gloves and goggles, while the inside lid has a handy key clip.
Performance and comfort
Technical mountain packs aren’t generally known for carrying comfort, since the emphasis tends to be on keeping weight down while ensuring good load stability. However, this was the one of the most comfortable packs I tested in the 2024 winter packs group test.
That’s thanks to its shaped back panel and well-padded harness, which Rab refers to as its ‘Tri-flex’ fixed carry system. The only caveat to that is that while the 18” fixed back length suited this 6ft+ tester, it might not suit shorter users.
Overall performance was near faultless. This pack swallows loads of kit and carries it well thanks to a robust internal frame.
I appreciated user-friendly features such as the side zip access to the main compartment, and liked its tough and robust build. High-quality metal components like the axe headlockers and lid buckle emphasise that this pack is built with longevity in mind.
It also has a good volume-to-weight ratio, being commendably light for its 50-litre carrying capacity. Among the winter packs I tested in 2024, only the smaller Alpkit Orion 45 and Mountain Equipment Fang 42+ were lighter on the scales.
Sustainability
Rab has used a combination of materials to construct this pack. The main fabric is made from 35% recycled 210D ROBIC nylon, while the base and sides of the pack are 50% recycled 420D mesh dobby.
ROBIC fabrics are up to 50% stronger, with up to 2.5x the tear strength compared to standard nylon 6. This means you get a very tough, durable face that withstands wear and tear very well.
It’s also coated with a Hydroshield water-repellent treatment and the fabric is highly resistant to UV degradation. The entire product is PFC-free.
All this is clearly expressed via Rab’s industry-leading ‘Material Facts’ user information.
Presented similarly to the nutritional information you find on food packaging, it aims to help outdoor users make informed choices by giving you the raw data.
Rab is totally transparent about what the pack’s made from, as well as how and where it's manufactured (Vietnam, in this case). I’d love to see more brands take the same approach.
Price and competition
With an RRP of £150 ($185), this was the second cheapest product in our 2024 winter packs group test, despite being one of the bigger packs in the 40-50 litre category. Shop around and you can find it for a little less, too, which makes it even better value.
In short, if you’re looking for a roomy and capable gear-hauler for mountain adventures, I think this is one of the best choices on the market.
There is the deluxe Gregory Alpinisto 50, which carries just as well and comes in multiple back lengths for a superb fit, but it’s a lot more expensive at £220.
If you want a versatile all-rounder with less of a technical focus – a pack that would work for winter hillwalking, scrambling or mountaineering, for example – then it’s worth looking at our multiple Best in Test winner, the Mammut Trion 50.
It sacrifices a little carrying comfort but is even more user-friendly, with lots of excellent features. It is £40 more expensive than the Ascendor, though.
Verdict
The Rab Ascendor 45:50L is a tough, roomy and well-built technical mountain pack with an easy-loading, easy-access design. It carries well if it fits, but only comes in one size.
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About the author
Matt Jones is a freelance journalist based in the heart of Snowdonia National Park, he’s a vastly experienced gear tester and self-confessed outdoor kit geek.
Matt’s been one of our main gear testers for the last couple of years and is the first person we call with any complicated kit queries that need in-depth and forensic analysis.