During testing, our Nano IX was asked to perform in each of climbing's many disciplines; from frozen first ascents in Alaska's Ruth Gorge to brutal top roping sessions in the Utah desert, with sport whippers and multi-pitch crack systems in between. It was even used by the author for a personal best redpoint that he still won't shut up about. Through these trials we were able to appreciate its exceptionally low weight and smooth handling, which became the primary reasons why it won our Top Pick award for best alpine/sending rope. It's not cheap, however, and the reduction in weight does seem to diminish durability. But we still like the Nano IX for anyone who considers low weight the most important criterion.
Sterling Fusion Nano IX Review
Cons: Low durability, expensive
Our Analysis and Test Results
The Nano IX is the lightest and thinnest member of Sterling's popular Fusion line of ropes. The sheath is made in the ubiquitous double-pick pattern but with a tighter weave than normal that improves handling and reduces rope drag.The UIAA has certified the Nano IX for use as either a single, half, or twin rope. Potential buyers should be aware of this caution expressed on Sterling's website,
At 52 g/m the Nano IX is the lightest rope we tested, and by a 3 g/m margin. This weight also makes it one of the lightest single ropes available on the market today. In a 60 meter length this would save you almost 2 pounds (900 g) compared to the heaviest rope we reviewed, the 67 g/m Mammut Sensor.
Phrased this way, it might not sound too substantial. When your pack already weighs 50 lbs, what's a pound or two more? But for ounce counting alpinists or uncooperative sport projects, it can make a dramatic difference. Additionally, the tight weave of the sheath reduces rope drag through quick draws, which can make this rope feel even lighter at the top of a long pitch.
We suspect a large portion of the weight savings is created by reducing materials in the sheath rather than core, so in a total force sense it should be as strong as its Sterling relatives. The UIAA tests support this speculation because it caught the same number of falls (6) as the Ion R and the 63 g/m Marathon Pro. But its sheath proportion is only 27% of total weight; much less than the Marathon Pro's 42%. As we will discuss later, this reduction negatively affects durability and could make the Nano IX more susceptible to abrasion or cutting on sharp edges.
Like all of our award winners, this rope received a UIAA impact force rating in the mid 8 kN range; at 8.5 kN exactly. Our testers confirmed that this rating, and the Nano IX specifically, provides a soft, gentle catch in most real world situations. We did observe, however, that the length of rope out and the distance of a fall, combined with the weight and motion of the belayer, have a much larger effect on the 'softness' of a catch than the properties of a rope by itself.
For static and dynamic elongation this rope was measured by the UIAA at 7% and 33.1% respectively. This static performance was about average and not particularly notable. The dynamic score was more distinguishing and tied it for second highest among all ropes reviewed. For difficult, likely overhanging, projects this is not a significant concern. During a fall you get to enjoy a little bit longer ride through clean air with the only downside being a few more boinks back to your high point. In the sometimes broken terrain of alpine routes—where this rope's low weight is so advantageous—the longer dynamic stretch could be a concern. When exposed to a ledge fall, any additional risk created by a potentially longer fall might be mitigated with a careful belay and extra gear placements.
With its skinny diameter and tightly woven sheath, the Nano IX offers some of the best handling over the majority of its lifespan of any rope tested. After an initial breaking-in period that lasted only a few pitches, it feeds smooth and supplely through many belay devices, including with Petzl GriGri 2s and Black Diamond ATC Guides (in regular or guide mode). Even at the end of our tests, after the sheath had grown fuzzy and collected lots of dirt, it maintained its pleasant hand and did not develop stiffness.
Fresh out of the package, however, this rope is slick; perhaps too much so. During the first few days of testing our reviewers had to be particularly attentive while belaying to ensure they would be able to catch any unexpected falls. The dry treatment seemed to exasperate this issue. With time though, it broke in and our fears of unarrested falls subsided. Be sure to check that your belay device is approved to handle a 9.0 mm diameter. We should also mention that this rope is sold drum coiled, which means a brief hassle before the first use when you have to uncoil and flake it to avoid snarls and kinking.
For any rope with a 9.0 mm diameter (and 52 g/m weight) durability will always be the biggest question mark. We believe most of the reduction in weight and diameter in the Nano IX is created by removing extra fibers from the sheath rather than the core. This creates an issue because in our experience, the sheath has the greatest impact on overall durability. As the outer layer it must endure the rubbing and scrapes of miles of rock while still looking and feeling trustworthy. As soon as a sheath gets even a small nick or excessively fuzzy most climbers are apt to retire the whole rope. Therefore, ahead of our tests, this rope's lowest overall sheath proportion, at 27%, was worrisome.
Now, after a thorough examination we must acknowledge that it does not provide the same durability as a 'workhorse' like the Mammut Sensor, or even many of the 'all-around' ropes reviewed. Its longevity, though, was better than expected; a performance we credit to the tight weave of the Fusion sheath that held up better than its diameter would suggest. But we caution users to take special care of any Nano IX and avoid harsh, repeated, uses. For your most important sport projects or alpine missions though, it can handle some abuse.
As we've stated many times now, this rope's greatest benefit is its low weight. The best applications for this quality are many and varied. We envision the most likely scenarios to be personally difficult single pitch projects or long alpine objectives. But other uses could make sense. It might work well for frequent airline travelers, helping them squeeze into a single bag or maybe just a carry-on. Older or injured climbers would likely appreciate the decreased carrying weight for lowering the burden on ailing joints. Free climbing big walls has recently gained popularity, and if you're strong enough, this is one more area where the Nano IX could excel.
For alpine routes where you will still need two ropes to rappel, we recommend pairing a Nano IX with the light and stiff tag line.
The pricing for this rope at the various lengths, bi-patterns, and dry treatments it is offered in is higher than average. A 70 meter dry version currently retails for $260. A bi-pattern sheath will add about $70 more. When you consider its limited durability, it is effectively even more expensive. In the skinny rope size class, however, it is an overachiever, and the high price tag may be justified by its great handling and soft catch. Compared to the similar ropes we tested, we do feel it offers a decent value.
The exceptional low weight and smooth handling are ultimately the reasons why the Nano IX took home our Top Pick award for the best alpine/sending rope. Shoppers should be aware that its small diameter did compromise its durability in our tests. But if you can stomach the fragility, this rope provides the weight savings to get you up your most ambitious goals.
Other Versions and Accessories
Sterling Marathon Pro
- Cost - 60m - $210 and 70m - $240
- 10.1mm diameter
- 63 grams per meter
- Top Pick Award Winner!
- An excellent, durable workhorse rope for a wide variety of climbing
- Cost - 60m - $205 and 70m - $240
- 9.8mm diameter
- 62 gram per meter
- Best Buy Award Winner!
- A versatile, multipurpose rope
OutdoorGearLab Member Reviews
Most recent review: June 9, 2015
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