2017 Sterling Fusion Nano IX Rope

Matt Zia reviews the 2017 Sterling Fusion Nano IX for Blister Review
2017 Sterling Fusion Nano IX

2017 Sterling Fusion Nano IX

Diameter (mm): 9.0

Rope Type: Single, Half, Twin

Sheath (%): 29

Weight (g/m): 52

Dynamic Elongation (%): Single: 26.4; Half: 27.6; Twin: 25.3

Static Elongation (%): Single: 7.0; Half: 7.0; Twin: 3.6

Impact Force (kN): Single: 8.5; Half: 6.6; Twin: 10.4

UIAA Falls: Single: 6; Half: >15; Twin: >20

Available Lengths (m): 30, 40, 50, 60, 70, 80 m

Bicolor Available: Yes

Length Tested: 70m, non bicolor

MSRP: $265.95 (70m, non bicolor)

Days Tested: 30

Test Locations: Gallatin Canyon, Absaroka Range, Bridger Range, & Beartooth Range MT; Wind River Range & Wild Iris, WY


Two years ago, Anneka Door reviewed the original Sterling Nano IX rope, part of Sterling’s Fusion line, and stated that it had firmly earned a place in her quiver for long alpine objectives due to its combination of durability, handling, and low weight. After also using the original Nano IX for two years, I agree with her assessment. This year, Sterling updated the Nano IX with a new dry-treatment called “DryXP” that combines the “DryCore” treatment already applied to every Sterling rope with a new sheath treatment that is claimed to keep water absorption to 1.8% of rope weight — well under the UIAA standard of 5% of total rope weight. Like it’s predecessor, this latest version of the Fusion Nano IX is rated for use as a single, half, and twin rope. So far I’ve only used the Nano IX as a single rope, though based on my experience with other ropes, I do not expect a difference in my assessment when the Nano IX is used in a double or twin rope situation.


Overall, the Fusion is one of the best handling ropes I’ve used. The rope feels supple and light when tying knots, belaying, and clipping. I’ve used the Nano IX with a wide array of belay devices such as the Petzl Grigri 2, BD ATC-Guide, Edelrid Mega Jul, and a munter hitch, and the Nano IX performed excellently with all of them. Like all dry-treated skinny ropes I’ve used, the decrease in friction due to the dry coating and smaller diameter combine to make belaying more challenging than thicker, non-dry-treated ropes. For this reason, I prefered to use the Nano IX with a Grigri 2 when single-pitch climbing as the Grigri 2 provides a higher level of security. However, when top-belaying I much prefered to use the Nano IX with a guide-style auto-blocking device like the ATC-Guide or Reverso 4 as the Grigri 2 tends to slip more before the assisted braking mechanism catches a fall.

Matt Zia reviews the 2017 Sterling Fusion Nano IX for Blister Review
Looking down at the N Face of Ambush Peak with the Sterling Fusion Nano IX, Wind River Range, WY. (photo by Matt Zia)

Unfortunately, the Nano IX is still not sold off the shelf in a butterfly coil, so taking the extra time to uncoil the rope properly before using it right away is key to avoid rope kinking. However, once uncoiled properly and flaked several times, the rope behaves just fine.

Dry Treatment

While the previous dry treatment used by Sterling did not meet the UIAA standard of water absorption equivalent to less than 5% of the rope weight, the new “DryXP” treatment claims a water absorption of under 1.8% of rope weight. On a late summer trip to the Absaroka Range in Montana, my partner and I endured scattered rain and hail storms all afternoon and the Nano IX shrugged off the precipitation well, even as we donned rain jackets and watched as our small backpack (and more importantly, bag of snacks) got drenched. At the end of the day while coiling the Nano IX, I could barely feel any moisture on the rope.

A better test came at the end of September, when I went on an early-season ice exploration trip into the Beartooth Range. My partner and I spent most of the day cursing our life choices as we grovelled up unconsolidated snow, rock slabs running with water, and even the occasional ice pillar. However, the Nano IX fared much better. At the end of the day, I could barely tell the rope was wet and it did not freeze up at all, a welcome respite from our day-long struggle with frozen slings and stuck carabiners.

Matt Zia reviews the 2017 Sterling Fusion Nano IX for Blister Review
Matt Zia with the Sterling Fusion Nano IX on early-season alpine ice, Beartooth Mountains, MT. (photo by Alex Wakeman)

Now it’s hard to say for sure that the new DryXP treatment made the difference between a frozen and a functional rope, but I do believe DryXP is an improvement over Sterling’s old dry treatment. When compared to other dry treatments on modern skinny ropes, I think the DryXP treatment is on par with the best. The only other dry treatment I’ve used that is comparable is the “Golden Dry” treatment from Beal. As I get more time on the Nano IX, I’ll update this review with any new notes about the dry treatment.

My one gripe with the DryXP treatment is that it seems to impart a tacky feel to the rope. While the tackiness does not seem to hinder the performance of the rope (and may in fact not be attributable to the dry treatment), it’s certainly an unexpected sensation when using the rope for the first time. Although my first thought was that the tackiness would increase the friction of a dry-treated rope (which are notorious for their slickness), I found very little difference in friction through a belay device between the Nano IX and other skinny dry-treated ropes I’ve used.

Middle Mark

The previous generation of Nano IX ropes were sold either as bicolor, or as a single color without a middle mark. Anneka commented on this difference and stated that spending the extra cash in the bicolor rope was a worthy investment. Luckily, Sterling now includes a black middle mark on the single-color Nano IX. I found the mark easy to find, especially on my bright orange version of the Nano IX, and still noticeable even after over 200 pitches on the rope. I agree with Anneka’s statement that not having a middle mark is annoying, time-consuming, and arguably dangerous, so I’m very happy to see that Sterling is now including the mark.


Sterling upped the sheath-to-core proportion from 27% in the original Fusion Nano IX to 29% on the current iteration. While 2% might not seem like a huge change, I’ve seen a marginal increase in the durability of the new Nano IX. On a summer alpine climbing trip to the Wind River Range, my partner and I climbed nearly 7000’ of coarse granite in four days, and despite making the regrettable life decision to climb a route involving multiple pitches of grovelling up squeeze chimneys (we somehow overlooked that minor detail before we started climbing), the Nano IX came through the ringer relatively intact. I did manage to abrade a section of the sheath all the way through to the core and had to cut the rope a couple meters from the end. Aside from that single spot though, I have yet to notice significant softening, fuzzing, or other widespread wear on the rope.

Matt Zia reviews the 2017 Sterling Fusion Nano IX for Blister Review
Matt Zia with the Sterling Fusion Nano IX, Wind River Range, WY (photo by Chris Dickson)

Although I don’t keep track of the exact number of pitches I put on my gear, my rough estimate is that I took the Nano IX up over 200 pitches, the majority being on coarse alpine granite and limestone. I also took the Nano IX out for several days of cragging at Wild Iris and various sport crags around Bozeman and took a large number of both small and large falls on the rope.

It is worth noting that comparable ropes such as the Mammut Serenity 8.7 mm and the Edelweiss Swift 8.9 mm have a sheath proportion of 38% and 34%, respectively. While I haven’t used the Edelweiss rope, I’ve climbed extensively on the Mammut Serenity for almost three years and the rope is still going strong. Generally speaking, ropes with a greater percentage of mass in the sheath are more durable, so I’m not surprised that the Nano IX developed sheath damage faster than the Serenity. I’ll update this review if I experience any durability issues with the Nano IX in the future.

Matt Zia reviews the 2017 Sterling Fusion Nano IX for Blister Review
Matt Zia with the Sterling Fusion Nano IX, Absaroka Range, MT. (photo by Alex Wakeman)

With all that said, there are inherent tradeoffs between rope weight, size, and durability. A 10.2 mm rope is pretty much always going to be more durable than a 9.0 mm rope. So if you are looking for a hyper-durable rope to whip all over a project, the Nano IX is not the rope for you. But if you need a lightweight rope to hike far into the backcountry or to use for a hard redpoint attempt, the Nano IX fits the bill.

Bottom Line

The Sterling Fusion Nano IX was an excellent rope when it was first released two years ago, and it’s still near the top of the pack for skinny ropes. The new DryXP treatment in particular is excellent; I think when combined with the higher sheath-to-core proportion and inclusion of a middle mark, the new Nano IX is definitely an improvement over the previous version of the rope. That said, if you’re looking for a super durable rope, there are slightly burlier options out there, even at similar diameters. So, while I wouldn’t go out and replace a perfectly good rope based on these factors alone, if you’re in the market for a new skinny dry-treated rope, the Sterling Fusion Nano IX is an excellent choice.

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