The world's most in-depth and scientific reviews of outdoor gear

Sterling Fusion Nano IX Review

This "experts-only" rope was our favorite option for long sport routes.
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Price:  $266 List | $234.95 at Amazon
Compare prices at 2 resellers
Pros:  Lightweight, great handling for a thin line, rated as a single, half and twin
Cons:  Expensive, not as durable as a thicker rope
Manufacturer:   Sterling
By Cam McKenzie Ring & Andy Wellman  ⋅  May 8, 2019
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70
OVERALL
SCORE


RANKED
#9 of 16
  • Handling - 35% 6
  • Durability - 25% 6
  • Weight - 20% 10
  • Catch - 20% 7

Our Verdict

The Sterling Fusion Nano IX is one of the lightest and thinnest climbing ropes in our test group, measuring out at only 9.0mm. While there are other specialty twin and half ropes (and even a couple of singles!) that are thinner and lighter, the Nano IX provides just the right amount of confidence for the diameter. It is a specialty line, which we explain below, and should only be used by those with a lot of experience belaying. It's also not your everyday cragging workhorse rope, though we did use it as such during our testing period to gauge its durability. We used it for long and winding 35-meter sport routes where we took some big whippers and then yarded ourselves back up again, and it withstood that abuse better than another skinny competitor, the Beal Joker. Though the Joker gave us more confidence in multi-pitch situations that traveled over suspect terrain and rock (thanks to its Unicore construction), if we had to choose one of them for our "epic-mega-proj" send days, the Nano would be it.


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Overall Score Sort Icon
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Star Rating
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Pros Lightweight, great handling for a thin line, rated as a single, half and twinSkinny for its diameter, durable, great catch, smooth handlingDurable, excellent feel and handle, soft catchesLight, durable, super soft and supple handleGreat handling, durable
Cons Expensive, not as durable as a thicker ropeSlightly stiff, middle mark wears off quicklyPriceyNot durable enough for heavy duty sport climbing, a lot of stretch when secondingHeavy for the diameter, high impact force rating
Bottom Line This "experts-only" rope was our favorite option for long sport routes.The top-performing do-everything rope that is also a crowd favoriteOne of the best ropes you can buy, striking a perfect balance between low weight and durability.The perfect light and skinny rope for climbing high above the groundA great rope for advanced sport climbing.
Rating Categories Sterling Fusion Nano IX Mammut Infinity Sterling Evolution Helix Petzl Volta Maxim Pinnacle
Handling (35%)
10
0
6
10
0
7
10
0
8
10
0
8
10
0
9
Durability (25%)
10
0
6
10
0
9
10
0
8
10
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7
10
0
8
Weight (20%)
10
0
10
10
0
6
10
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6
10
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8
10
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5
Catch (20%)
10
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7
10
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9
10
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8
10
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7
10
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6
Specs Sterling Fusion... Mammut Infinity Sterling Evolution... Petzl Volta Maxim Pinnacle
Diameter 9 mm 9.5 mm 9.5 mm 9.2 mm 9.5 mm
Weight (g/m) 52 g/m 59 g/m 59 g/m 55 g/m 61 g/m
Certified Use Single, Half and Twin Single Single Single, Half and Twin Single
UIAA Fall Rating 6 8-9 7 6 7
Impact Force 8.5 kN 8.4 kN 8.9 kN 8.6 kN 10.3 kN
Static Elongation % (in use) 7 6.5 7.2 7.5 5
Dynamic Elongation % (first fall) 26.4 30 31.9 33 26
Sheath Proportion % 29 40 41 42 36
Dry Coating Option Dry XP, Dry Coat Mammut's Dry Treatment DryXP Duratec Dry Endura Dry 2x treatment
Middle Mark or Bi-Pattern Option Middle mark, Bi-pattern option Bi-Pattern or Middle Mark Middle Mark and Bi-Color Option Middle Mark Bi-pattern option
Lengths Available 30m, 40m, 50m, 60m, 70m, 80m 50m, 60m, 70m, 80m 40m, 50m, 60m, 70m, 80m. DryXP: 60m, 70m, 80m 50m, 60m, 70m, 80m 60m, 70m

Our Analysis and Test Results

EXPERIENCED CLIMBERS ONLY!
We need to take a moment before we start this review to mention that ultra-thin lines like the Nano IX, Edelrid Swift Eco Dry, and Beal Joker are for experienced climbers only. These specialty lines serve a great purpose for those looking to move fast in the alpine or send a hard and long sport route, but they are more difficult to use than the "thicker" ropes in this review. Even our experienced testers found it a little more worrisome to catch a big fall with these lines. Not all active assist belay devices will grip one of these super thin ropes, so check yours before you belay with one. They will also not last as long as a thicker rope and are more expensive, so they are not intended for everyday use. Sterling even has the following warning on their website: "Due to the Nano's small diameter, it is recommended that it only be used by experienced climbers and belayers and NOT for top-roping or working of routes. It is critical that proper belay devices be used and extreme caution should be taken."

The Sterling Fusion Nano IX is a 9.0 mm rope that weighs 52 g/m, making it one of the thinnest and lightest lines that we tested. It is rated for single, twin and half use, and it's available up to 80m.

Performance Comparison


Testing out the Nano IX at Smith Rock  OR. This lightweight line is great for long sport climbs where you want to lighten up as much as possible  but it should only be used by experienced climbers and belayers.
Testing out the Nano IX at Smith Rock, OR. This lightweight line is great for long sport climbs where you want to lighten up as much as possible, but it should only be used by experienced climbers and belayers.

Handling


We tested the Nano IX side-by-side with the Joker from Day 1 to compare their handling against each other. The Joker felt slick to start, and we had issues with some slippage in our GriGri 2, (note: new Petzl GriGri is able to handle ropes down to 8.5mm in diameter) which did improve with time. The Nano, on the other hand, had great handling out of the box, without feeling too slippery or slick. Sometimes the dry treatment that a manufacturer uses can end up leaving what feels like a slick residue on the surface of the rope, but we didn't notice it with Sterling's DryXP treatment (UIAA Water Repellent certified for less than 5% water absorption). The Nano IX continued to have great handling throughout our testing period, though right towards the end (around the 80 pitch mark), we noticed that it was starting to stiffen a little. A quick trip through the washing machine solved that problem, and it continued to handle better than the Joker.

We liked the handling on this line  particularly when making fast clips on a sport route.
We liked the handling on this line, particularly when making fast clips on a sport route.

That being said, it is still a skinny line, and it's generally harder to control a belay when compared with a thicker 9.7-9.8 rope, which is why its overall handling score is lower than some other models in this review. Gloves help with this a lot, as does experience. Be sure to look at your belay device carefully and consult the specs. Petzl's new GriGri+ can accommodate ropes down to 8.5 mm, and should help give you a bit more piece of mind when branching into the skinny rope world.

We had no slippage issues when using the Nano with a GriGri 2 and it certainly fed better through that device than a thicker 10mm rope   however  it is more challenging to belay with a skinny rope as they are generally harder to hold on to when arresting a fall and lowering your partner. Wearing gloves helps.
We had no slippage issues when using the Nano with a GriGri 2 and it certainly fed better through that device than a thicker 10mm rope, however, it is more challenging to belay with a skinny rope as they are generally harder to hold on to when arresting a fall and lowering your partner. Wearing gloves helps.

On a final note, the middle mark on the purple line that we tested was almost impossible to see, and it wore off quickly. If you need a distinct middle mark for frequent rappels, consider a lighter color or even better the bi-pattern option.

Catch


We didn't notice anything particularly hard about the catch on this rope, other than we always hoped our belayer was holding on tight! Neither the Nano IX nor the Joker had quite as much elongation as most of the thicker lines that we tested (26 and 24% vs. the 38% of the Beal Booster), but that wasn't always noticeable in a real-world fall scenario with a dynamic belay.

Falls felt great on this line as long as there was sufficient slack out. We did notice a bit of stiffening after the 80 pitch mark though.
Falls felt great on this line as long as there was sufficient slack out. We did notice a bit of stiffening after the 80 pitch mark though.

Weight


Here is where the Nano IX beat all of the other models. At only 52 g/m, it is easily one of the lightest lines in this review, tying the Edelrid Swift Eco Dry for that honor. But what does that mean for you? A 70-meter length of the Nano Ix should weigh around 8 pounds, which is almost 2 pounds less than a heavier 64 g/m rope like the Black Diamond 9.9. That difference is certainly noticeable in your backpack, as well as at the top of a long route. However, that weight savings does come at the cost of the next metric: durability.

This rope is so light and thin that the 70-meter version that we tested weighed about the same at the 60-meter version of the thicker ropes in this review. That difference was appreciated on long hikes into a long route.
This rope is so light and thin that the 70-meter version that we tested weighed about the same at the 60-meter version of the thicker ropes in this review. That difference was appreciated on long hikes into a long route.

Durability


When compared to the other lines in this review, there's no question that the skinny ones are less durable in the long term. While a thicker "workhorse" rope could last you for years if you put the same cragging and top rope use on one of these it probably won't. That's because there's less material in the sheath as a percentage of the overall rope (only 29% for the Nano compared to high 30's and low 40's for thicker lines), and most ropes get retired due to sheath damage. We did treat this line like a cragging rope though and have to say that we were impressed with how much better it looked than the Joker after about 80 pitches. The Joker's sheath was significantly more abraded after similar use, and we had some nicks close to the ends. The Nano's sheath did have some "glazed" sections though, and the Joker's Unicore construction gives it an edge in Alpine situations. We ended up rating them similarly for this category, but prefer the Nano for sport cragging if you insist on going skinny! That said, our favorite choice for sport climbing on a skinny rope is the Edelrid Swift Eco Dry, so be sure to take a look at that one as well if you are purchasing a long send line.

This rope was still looking great after 80 pitches  with only little "glazing" and minimal fraying. However  the middle mark dissapeared on us!
This rope was still looking great after 80 pitches, with only little "glazing" and minimal fraying. However, the middle mark dissapeared on us!

Note that we heard a lot of anecdotal reports (and read some online as well) about these thin lines getting a core short on the first pitch of XYZ after getting stuck behind a flake etc., etc. Is this necessarily the rope's fault? An 11m line might have had the same issue in the same situation. While our durability testing is not exact lab conditions, we do strive to put the same amount of wear on the same type of rock, and both lines came on road trips to Smith Rock, OR and Independence Pass, CO.

Best Applications


Thinner lines are not for everyone, and should not be used on every route. We ended up testing this rope at a fresh (i.e., sharp!) limestone crag one day, and we were terrified with every lower and every fall, wishing we'd brought Sterling's Evolution Velocity 9.8 mm with us instead. But, if you are looking for something light for that long route you've been eyeing, then the Nano XI is a great choice. For international sport climbing trips where 80m ropes are necessary to access the heaps of classic limestone you've been reading about, thin ropes like this one make a good choice as they are lighter in your luggage and also at the top of those extra long routes.

Staring down the impending crux on an onsight attempt of Glory Daze  a 35-meter wandering 12c at the Robber's Roost  NV. This rope is great option for these situations  and anytime where a lightweight line could make a big difference.
Staring down the impending crux on an onsight attempt of Glory Daze, a 35-meter wandering 12c at the Robber's Roost, NV. This rope is great option for these situations, and anytime where a lightweight line could make a big difference.

Value


The cheapest you can get this line is $265 for the 60m, but, since most people are going to want it in a 70 meter (or longer!), then it will set you back $305. The bi-color option ranges from $295-$340! Considering that this line probably won't have the same longevity as a thicker one, if you do spring for then we'd recommend pulling it out for "special" occasions and not for everyday use. The Joker is priced a little more reasonably ($220-250).

Conclusion


We like a lot of things about the Sterling Fusion Nano IX. It's lightweight, handles well, and it fared pretty well during our tests. This is a great rope for certain situations, like a hard onsighting on a long route, but it's not the best everyday cragging rope. The new DryXP treatment also makes it suitable for Alpine and Ice climbs, though the rise of the Unicore lines has us preferring them in those situations due to the extra bit of safety that they provide. The Nano is still a great line though, and we'll be bringing this one out for those routes that go on forever.


Cam McKenzie Ring & Andy Wellman