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Sterling Fusion Ion R Review

Sterling Fusion Ion R
Sterling Fusion Ion R, 9.4 mm
Credit: Sterling
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Price:  $246 List
Pros:  Exceptional handling, lower weight
Cons:  Reduced durability, above average price
Manufacturer:   Sterling
By Jack Cramer ⋅ Review Editor  ⋅  Jun 9, 2015
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  • Weight - 20% 7.0
  • Catch - 15% 8.0
  • Handling - 40% 9.0
  • Durability - 25% 4.0

Our Verdict

The Fusion Ion R, with its 9.4 mm diameter and 57 g/m weight, occupies an interesting place in between size categories. Not quite light enough to save for only your desperate projects, yet not really sturdy enough to handle the grind of full time use. We dragged it up frozen waterfalls, desert towers, and overhanging jugs where it consistently performed well. Our testers particularly loved its supple hand and the soft catches it provides. With just a little more durability it might even have outclassed the Mammut Infinity for our Editors' Choice award. Nevertheless, you can see from the impressive final score it received that we liked it a lot. Shoppers looking for sound overall performance with an emphasis on low weight should consider it an option.

The Best Rock Climbing Rope Review compares the Fusion Ion R and eight of the other most popular climbing ropes side-by-side.

Our Analysis and Test Results

The Ion R is the thickest option in Sterling's Fusion line of ropes. This is their fancy way of saying that it has a tightly woven sheath like the Nano or Photon. This design feature makes it expensive compared to their more economical Marathon and Evolution series, but also gives you less rope drag and better handling. The special weave of the sheath also allows for unique speckled colors, including the extremely bright orange of our test rope that seemed to radioactively emit light and prevented our camera from auto-focusing on it.

Performance Comparison

Sterling Fusion Ion R climbing rope - the fusion ion r may be able to catch 6 uiaa test falls but that...
The Fusion Ion R may be able to catch 6 UIAA test falls but that doesn't mean you should lose your focus while dynoing (especially when your belayers hands are full).
Credit: Jack Cramer


This rope was the third lightest overall with a weight per meter of 57 grams. For its diameter, 9.4 mm, this is impressive—the 9.5 mm Edelrid Eagle Light is a full 5 g/m heavier. However, diameter measurements are not standardized between manufacturers and can appear to be drastically different in hand. At this light weight we classify the Ion R on the cusp between 'alpine/sending' and 'all-around' rope. With this weight you can expect better longevity than the thinnest ropes on the market, but not enough to handle continual hard use.


We found the Ion R provided a pleasant, soft, catch after falls, and we know because our testers took a lot of them. The UIAA gave it an 8.7 kN in their impact force test—the most objective way to measure 'catch'—which places it just above the lowest rated Sterling Nano IX. This score also keeps it within a decimal point or two of all four of our award winning ropes. Having recognized this pattern we suggest to shoppers that they look for a similar number if they decide to search for a deal outside the ropes we've tested.

Like all Sterling ropes reviewed, it withstood 6 falls in the UIAA fall rating test.

Sterling Fusion Ion R climbing rope - drew smith at the bottom of a long, stretchy, fall with the sterling...
Drew Smith at the bottom of a long, stretchy, fall with the Sterling Fusion Ion R.
Credit: Jack Cramer


This rope is a joy to manage. The sheath is more tightly woven than others tested. This helps reduce rope drag during leads and strain while belaying from above in auto-block mode. At the same time, its 9.4 mm diameter is thick enough to lessen the worry of dropping your partner that can be a problem with the thinnest ropes. However, be sure to test any rope carefully with your belay device and always stay alert while belaying; particularly when a rope is new and the friction is lower.

Sterling Fusion Ion R climbing rope - initially the smooth finish on the sterling fusion ion r would slip...
Initially the smooth finish on the Sterling Fusion Ion R would slip in a Grigri 2 but after a couple days of use it handled perfectly.
Credit: Jack Cramer


The same low weight that makes this rope nice to carry compromises its durability. This shortcoming is not unique to the Ion R and would be seen on any 9.4 mm rope weighing 57 g/m. Additionally, its sheath proportion is 37% which places it in the bottom half of the ropes we examined, but only by a little. These qualities resulted in a rope that got beat up quickly in our tests. On the positive side, we can report that it was able to arrest repeated falls while still providing a soft catch, and we did not observe any sheath slippage.

Best Applications

At this diameter and weight the Ion R is ideal for a wide range of disciplines. It is light enough to be useful on alpine objectives while still burly enough to handle the abuse of occasional falls. We like it most for climbers that want a skinny-ish rope for hard redpoints or light, missions but already have a hardier rope or regular daily use.


For the standard, non-dry, 70 meter version of this rope the suggested price is $246. This price is close, if slightly higher, than many of the ropes we tested. It costs about $10 more than the Best Buy winning Sterling Velocity for most of the available options, but you receive a rope that delivers substantially better performance.


As rope diameters creep ever lower, the Ion R represents the next generation of all-around ropes that are also exceptionally light. We were impressed by the soft catch it gave and the tight weave of the sheath that provided great handling. Durability was sacrificed for its low weight, but for certain applications, or at the right price, this could be a great rope to buy.

Sterling Fusion Ion R climbing rope - the sterling fusion ion r beginning to show wear but surrounded by...
The Sterling Fusion Ion R beginning to show wear but surrounded by the beauty of Arches National Park, UT.
Credit: Jack Cramer

Other Versions and Accessories

Sterling likes to offer their ropes with lots of different options and in multiple different sizes. It is no different with the Fusion Ion R, which comes in a standard or a bi-pattern finish (the Fusion Ion R Bi-Color) and with or without a DryCoat treatment. The most common lengths are also available: 50, 60, 70, or 80 meters. And in addition to the bright orange we tested there are four more color options.

Jack Cramer
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