If you are in the market for a new climbing rope you've come to the right place! We tested a variety of lines from the top manufacturers to help you get the most from your purchase. After researching over 70 different models, we put the 12 best through our side-by-side comparison testing process. After climbing, coiling and carrying each one, and catching numerous falls, we've parsed their various characteristics down to the most minute details. We climbed for months and covered over 20 vertical miles in our quest to find the best climbing rope, and have some great recommendations for top all-around performers, budget picks, skinny sends lines, and some solid workhorse options. Below we'll outline our favorite ones to help you in your purchasing decision, whether it's for your next gym session, your fifth line this year, or your first ever rope purchase.
The Best Rock Climbing Rope
We've updated our climbing rope review just in time for Rocktober! We spent the summer climbing long routes on skinny lines, and have some great recommendations for those looking to go light in the mountains or on their mega-long projects. We tested the Unicore version of the Beal Joker, and it won our Top Pick award for Alpine and Multi-Pitch climbing, but we also really liked the Sterling Fusion Nano IX. Keep reading below to see why!
Best Overall Rock Climbing Rope
Our Editors' Choice award goes to the Mammut Infinity, a durable and versatile 9.5 mm climbing rope. It weighs 58 g/m and handles smoothly, whether you choose to belay with a GriGri or an ATC style device. The thinner diameter and light weight make it appealing for long approaches and multi-pitch climbs, but it works equally well on sport routes, and the lighter weight is always appreciated there as well. This rope comes with a range of water repellent coating treatments: the Classic (no treatment), Protect (sheath only), and Dry (core and sheath). According to Mammut, both the Protect and Dry treatments increase the abrasion resistance by an astounding 40 and 50% respectively, but they do add to the cost.
Speaking of costs, this is an expensive line, and the Dry treated bi-pattern version that we tested was the most expensive model in this review ($280). The Classic can be purchased at a much more affordable $150 price point though. The 9.5 mm diameter might be a little thin for newer climbers, but it never felt slippery in hand to our experienced belayers. If we had to buy only one rope for all of our climbing applications, we would pick the Infinity.
Read review: Mammut Infinity
Best Bang for the Buck
Beal Booster III
With climbing ropes available in so many different lengths, sheath treatments, and weave patterns, it can be difficult to tell which one is a good value. As we mentioned above, the Mammut Infinity's price ranges from $150 to $280 for a 60 m, which is a significant difference. Enter the Beal Booster III which costs between $190 and $210 (Classic or Dry). While still not the least expensive line in this review, the combination of price point, performance, and durability made it stand out in our minds, and we've given it our Best Buy award. The Booster has been in production for over 20 years, but if you tried this line years ago and didn't like it, it's worth taking another look. Beal has taken the "softer is better" approach with the Booster III, and it has the highest dynamic and static elongation of any line in this review coupled with the lowest impact force rating. This makes it a great choice for trad climbers who want to minimize the force applied to their gear in a fall.
Top ropers and seconders should be a little careful with this rope, as it does have a lot of stretch to it. That could cause you to fall farther than you anticipate while seconding, which is always a little disconcerting. It felt a little stiff when new, but the handling softened up a bit with use. It was also one of the most durable lines in this review, and aside from a little dirt accumulation in the sheath, it looked almost new after over 70 pitches, which bumped up its value even more in our estimation.
Read review: Beal Booster III
Top Pick for Alpine and Multi-Pitch Routes
Sure, there are skinnier lines out there — and those who regularly use twin and half rope techniques might find the 9.1 mm Beal Joker to be on thick side! The rest of us who aren't used to "dental floss" lines but need something for long routes should consider the Joker. Constructed with UNICORE technology, the sheath gets bonded to the core to prevent sheath stripping in the case of a deep slice. While this can happen on single-pitch routes too, the consequences on a long route are often greater, and the Joker will stay more intact than a traditional line, giving you more options for retreat.
The Joker is not for every application though, nor for every climber. It's harder to handle than the thicker 9.9 mm and up ropes that most people start climbing on these days, and our testers experienced some worrying slippage when we were breaking it in. While it's handling improved with use, it also showed signs of wear faster than it's thicker sister line mentioned above, the Booster III. You could easily chew through this rope in a season by using it as your main cragging line. Instead, keep this one in the closet except for days when you plan to put air below your feet, or you are particularly worried about some sharp rock on your route.
Read Review: Beal Joker
Top Pick for Sport Climbing
Our testers really like the Maxim Pinnacle, but while our Editors' Choice winner is a great all-around climbing rope, this one is more specialized and is not suitable for all applications or all climbers. It has great handling, and we were able to give out slack quickly for fast sport clips, and the falls felt soft each time, regardless of the impact rating. We like the 5% static elongation for top rope burns, and the tight 1x1 sheath did a great job of keeping out the dirt, with the rope still looking almost like new after 70 pitches.
Though we didn't notice that this rope had harder catches than others, the high impact rating (10.3 kN) makes it a better choice for sport climbing than trad routes on marginal gear. This 9.5 mm line has a unique feel that is soft and supple in hand, but it might feel slippery to a novice belayer. That, combined with the thinner diameter, could make it more challenging for someone without a lot of experience belaying to arrest a fall, so we do recommend that you use all "thinner" diameter ropes with extreme caution (9.5 mm and under). That being said, if you're done with anything over 9.5, love fast clips and even faster feeding action when belaying, you need to check out the Pinnacle, as it feels like no other rope you've ever used.
Read review: Maxim Pinnacle
Top Pick for a Workhorse Rope
Sterling Evolution Velocity
While the 9.8 mm Sterling Evolution Velocity hovers at the lighter and thinner end of our workhorse rope classification (62 g/m), it was our favorite option for working a route and all-around heavy use. This rope has a long lifespan, which we can attest to having personally used it for years in an unforgiving desert environment full of sand and sheath destroying edges. During our side-by-side tests, it performed well for the diameter, with good handling and soft catches.
It's a few grams lighter than other ropes in the 9.8-9.9 mm range, but considerably heavier than some of the 9.5s in this review. Those looking to lighten their packs should look elsewhere. The Evolution Velocity can be used for any climbing discipline though, from ice to difficult sport climbing, and is versatile enough for the well-rounded climber to bring along on every new mission. We recommend it as someone's first climbing rope, the rope for someone who will only own one rope, or as part of a rope quiver to bring out for the hang-dog days.
Read review: Sterling Evolution Velocity
Top Pick for Top Roping and Gym Climbing
Black Diamond 9.9mm
Black Diamond finally dipped their toe in the climbing rope business, and we're sure glad they did. We tested the workhorse/gym oriented 9.9mm line for this review, as it is already one of the most popular ropes on the market after only one season. They do make a whole range of climbing ropes now, and if the other models, like their 9.6mm and 9.2mm, are as well-constructed as this one, then you're sure to like them. It provides a soft catch while not being too stretchy for top roping (7.6% static elongation), which is key to helping newer climbers feel secure on TR and helping to eliminate ankle injuries if they slip off close to the ground.
The 9.9mm is definitely on the heavier and thicker end of the spectrum, but that makes it an excellent choice for certain applications, as well as newer climbers. It does not come with a dry treatment though, so if you do climb ice, then this wouldn't be the best option for you. The price point is great though, at only $150 for the full 60 m rope, and $80 and $90 for the 35 and 40 m dedicated gym lengths. No more ruining your redpointing line in the climbing gym — just pick up one of these instead!
Read review: Black Diamond 9.9mm
Great for long and hard sport routes
Sterling Fusion Nano IX
Have a 35 or 40-meter sport project that you are working on? Consider the Sterling Fusion Nano IX. At 52 g/m, this is the lightest option in our test group, and the difference is notable, particularly after you hit the 30-meter mark, but your route keeps going. While we preferred the Beal Joker for lightweight alpine applications thanks to the Unicore construction, the handling on the Nano IX was a little better, and it felt more secure in hand, particularly when catching big falls. The new DryXP treatment that Sterling recently developed didn't feel slippery even when brand new, which is particularly important when using a thinner line like this one.
The Nano is not suitable for all climbers or situations though. It requires an expert hand to belay properly with a thinner line, and it won't last very long if you use it for top-roping sessions over sharp rock. Instead, save it for those long routes where shaving every ounce possible could be the key to success. While it might not as last long as a thicker line, with careful use you can extend the lifespan of the Nano and appreciate it even longer.
Read Review: Sterling Fusion Nano IX
Analysis and Test Results
There is quite an impressive selection of dynamic climbing ropes on the market today. Each rope has a long list of technical specs and numbers which can make deciding on the one that is best for you a bit overwhelming. In fact, we found that comparing ropes turned out to be much harder than expected. All of the ropes performed the basic functions of catching falls and protecting climbers, and none were inherently unsafe, so what are the main differences? We put our experience and knowledge to work for you, using a group of 10 testers who each had at least 20 years climbing experience, and some close to 40 — yes, we're an old bunch! While we occasionally had differences of opinion regarding handling or catch, after much discussion and collaboration we were able to come to a consensus on each rope's handling, catch, and durability relative to the others. Read on to see what we discovered, and what to look for when searching for an inexpensive model.
It can sometimes be hard to compare the various prices of climbing ropes due to the different lengths available, dry treatment options, and specialty weaves. The price of our Editors' Choice winner, the Mammut Infinity, ranges from $150 for a non-dry 60 m single color model to $280 for a bi-pattern dry-treated one. We tried to compare apples to apples in this review, and have listed the prices for the 60m dry treated version in most cases. If you are new to climbing and purchasing a lot of gear at once, you'll appreciate saving a few dollars on each purchase. If you're on a budget, look for a rope that earned a good score at a modest price, like the $150 Black Diamond 9.9 (not dry treated) and the $210 Beal Booster III. Another value factor to consider is the durability of the line (which we discuss below), particularly when you are just starting out and may not be aware of all of the ways to increase the longevity of your rope.
This category describes our overall impression of using each climbing rope. We evaluated each model on its suppleness and the overall feel while carrying, coiling, climbing, clipping, and belaying with it. This handling score accounted for 40% of the overall score — that's how important we feel this category is. It is also subjective, with some testers preferring thinner ropes over thicker, or vice versa, and so we polled ten different testers to get an overall impression as opposed to only one person's opinion. We also compared the feel of each one when brand new vs. broken in to determine if there was any stiffening or loosening up. Here's how we rated the various lines for handling.
In general, the models in the 9.5 to 9.7 mm range handled the best. Thinner diameters allow the ropes to be more flexible, and the light weight makes them less cumbersome to carry and clip. The top performers in this category were all 9.5 mm lines, including the Maxim Pinnacle, Mammut Infinity, and the Petzl Arial. We also liked the handling on the BlueWater Ropes Lightning Pro 9.7 mm. We were most impressed with the handling on the Maxim Pinnacle and gave it a 9/10 for this category. It feels like no other rope out there, and it has a smooth and supple hand feel without being slippery or noodle-like.
The Mammut Infinity, our Editors' Choice winner, has a more standard hand feel — not quite as smooth and you can feel the weave pattern — but still felt great both while clipping and belaying. We were also surprised and pleased by the handling on the Petzl Arial — it had been a few years since we've used their ropes, and Petzl changed their manufacturing partner in that time. Their current offering clips and feeds smoothly, and was a top favorite of our testers.
We also liked the handling of the Sterling Fusion Nano IX, and it fed through our GriGri smoothly. However, this and Beal Joker can be more challenging to hold on to when stopping a fall. These, and even some of the 9.5 mm lines, may not be the best choice for a newer climber. Using gloves can help, as does a lot of practice with a thicker line first. If you're reading this review and are new to the sport, we strongly suggest you purchase a 9.8 or 9.9 mm first. You could even go as thick as a 10.3 mm, but with so many belay devices designed for thinner ropes now, a thicker rope might work against you. While Petzl states that the GriGri 2 can work well with ropes up to 10.3 mm, our testers felt like 10.3 mm was just too thick for effective belaying with that device, and it locked up too much with a line that thick. Our Top Pick for a Workhorse Rope, the 9.8 mm Sterling Evolution Velocity, or our Top Pick for Top Roping and Gym Climbing, the Black Diamond 9.9mm, are better choices for newer climbers, as they still handled well for the size.
Finally, we have to mention our least favorite line for handling, the Edelweiss Curve Unicore Supereverdry. This rope uses the "Unicore" technology, where the sheath is bonded to the core. This prevents the sheath from slipping in case of a total cut to the sheath, and you can still descend safely on one of these lines in case of that happening. This construction is an important safety feature for rope access workers, as well as alpine climbers and mountaineers, where you'll still need to rely on your rope to get you down safely even in the event of a sheath slice. We've used "Unicore" dynamic ropes from other manufacturers, including the Beal Joker, and still found them to be supple and flexible, but not so with the Curve. We didn't test the regular Curve either, so we can't tell you whether this was the rope itself or the "Unicore" construction, but the result is not good. As you can see from the photos below, this line is stiff and wire-like, and it feels like you need to force it through a belay device, resulting in short-roped leaders and exhausted belayers.
Rating the catch of a rope is a highly subjective affair. We took a lot of falls on each line, and did so with the same two people who weigh the same and have been climbing together for years. We know what to expect from each other's whippers, how much slack to feed out, and what a "soft" or "hard" catch feels like. And in many instances, it was very difficult to tell the difference between the different models in this review. For one, the faller is simultaneously thinking "I can't believe I fell off that move AGAIN!" along with "I hope I don't die!" while trying to notice if this one line is bouncier than the previous one. But most importantly, there are so many other factors involved with what makes for a hard or soft catch beyond the rope, which we'll discuss below. All that being said, there are some significant differences between the way different ropes catch falls, and so we felt like it warranted a testing metric. Here's how we scored the various lines for their catch.
Climbing ropes help absorb the impact of your fall (which is really your deceleration), by stretching. Some ropes stretch more than others, and the range in our test group was between 24% and 38% maximum Dynamic Elongation. Note that this value is measured during the standard UIAA drop tests that involve unrealistic scenarios for everyday use. For example, if you fall right by a bolt with 50 feet of rope out on a line with 38% elongation, the rope will not stretch 20 feet. You may find yourself 5 feet down by the previous bolt due to a combination of rope stretch and any extra rope out though. While the dynamic elongation figures do give a good indication of the stretchiness of the rope, we couldn't always tell the difference when falling, and in fact had some of the "hardest" falls on the BlueWater Ropes Lightning Pro, which didn't have particularly low elongation or high impact force ratings, but more on that in a minute. The chart below shows the various dynamic elongation ratings for each model.
After falling on all of the lines multiple times and noting if anything seemed out of the ordinary, and also considering the top rope feel of each line, we "liked" falling the best on the Mammut Infinity and the Petzl Arial. Interestingly, these lines do have similar impact ratings and dynamic elongation (8.6 kN and 8.8 kN, and 30 and 32%). These ratings seem to hit a sweet spot between providing a soft catch, stretching just enough but not too much, and not feeling like a bungee cord when top roping. While we mentioned that you aren't likely to reach the full dynamic elongation in a real-world scenario, an extra foot or two of stretch could result in hitting a ledge or the ground, so those ropes with the highest stretch should be used with caution. As with the maximum dynamic elongation figures, the impact force ratings are the maximum recorded in a very controlled and unrealistic scenario. "Real" climbing falls typically generate much lower forces than these. The chart below shows the impact force ratings of each line.
The impact force is related to but not directly equal to the elongation. That means that two ropes might have the same elongation, but different impact force due to construction and materials. However, models with lower stretch do tend to have higher impact forces and vice versa. The Maxim Pinnacle had the highest impact force rating in this review (10.3 kN), and the lowest elongation (26%). While we didn't notice this during our test falls — the catches all felt fine and soft — this does mean that there is the potential for greater forces on your protection with this line vs. the 7.3 kN Beal Booster III. If you're only falling on well-placed, bomber bolts, that might not be a huge concern, but for traditional climbers, this higher impact force is something to consider, as smaller wires are rated between 2 and 6 kN, and thin cams only 8 kN.
We found the catches similar on the two "skinny" lines in this review, the Beal Joker and Sterling Fusion Nano IX, and while they both felt soft, we did take a point off due to the difficulty of holding on to a thinner line. We even had some slippage in with the Joker when using a GriGri 2 (the 9.1 mm rope is within its range but not in the "optimal" zone), and you should always make sure that the belay device that you are using is recommended for the diameter of your rope. We like the catch on the Trango Lotus, Beal Booster III, and Sterling Evolution Velocity, though the first two are on the stretchy side and care should be taken when top roping with those models. This leads us to a final spec to consider, the static elongation.
This was probably the easiest rating to correlate to real-world use, although again the number on the package isn't exactly what you'll experience. This test involves hanging an 80 kg mass on the end of the rope in a tower, with no other source of friction in the system. Once a rope is in a top rope configuration, and the belayer already has some tension on the line, part of that elongation will already be reduced. But, we've all been in those situations where we are on top rope, feel like there's tension on the line and rest on it, only to sink a few feet lower. A rope like the Beal Booster III will stretch more than the Maxim Pinnacle in this situation. Regardless of the stated elongation, a belayer should always take the time to take a bit of the stretch out at the start of a top rope, just in case the climber falls in the first few feet, to help keep them from hitting the ground.
If you're still with us then you might remember us mentioning the BlueWater Ropes Lightning Pro at the top of this section. This rope looked good on spec (7.8 kN impact force, 32.3% dynamic elongation), but the falls we took felt hard. We particularly noticed this on one occasion where we were working a harder route and taking successive falls in the same spot. The first fall felt noticeably hard with the standard amount of rope out. (The route was dead vertical and the draws all in a line.) On the second fall, the belayer let even more rope out than normal, but that fall felt even harder, and by the third, we were done with falling on this line. Both the climber and the belayer felt the jarring effects. This brings up the point of ropes needing to rest between falls in order to rebound. Black Diamond has done some interesting testing in this area and concluded that higher forces are exerted in successive falls and that it requires both time and/or switching ends for climbing ropes to rebound. But, they conducted the tests on one type of rope and didn't compare the rebound rates of different ropes. We think this would be an interesting next test because we didn't have this noticeable of an increase in impact force on any other line (and we took successive falls on all of them while working a route).
As a final note for catching falls, there are many things that both the climber and belayer can do to decrease the forces of a fall, including: a dynamic belay action (jumping up a bit when the climber falls), having sufficient rope out but not too much (typically a gentle c curve is sufficient, the bottom of which should not be touching the ground), and minimizing rope drag on a route, which ends up shortening the amount of rope that can actually absorb the impact and thereby increases the fall factor. Switching ends between burns also helps, as does switching ropes if you're climbing on back to back days.
Diameter and Weight
For this review, we chose to test "single" climbing ropes between a relatively narrow range of 9.0-9.9 mm. While climbing ropes are manufactured in various uses (single, half, and twin) and a wide range of sizes (7.8 mm to 11 mm), the majority of climbers use options in the above-mentioned range, and it would be like comparing apples to oranges to have a set of 7.8 mm half ropes in this review along with a 10.5 mm behemoth of old. If you're not sure of the difference between single, half and twin lines, you can head over to our Buying Advice article where we break all that down further.
Diameter is the easiest and most obvious way to judge a rope. When you hold a climbing rope in your hand, the thickness is the first thing you can tangibly feel. Therefore, it tends to be the feature that consumers focus on the most when purchasing a new one, with the current trend leaning toward thinner and thinner ropes. Black Diamond has even chosen to use diameters as the names for their climbing ropes. However, we think the trend of focusing solely on diameter is slightly misguided. Many people look for a skinny rope because they want one that is lightweight, but modern technology has allowed manufacturers to produce thinner cords with the same amount of materials, and therefore the same amount of weight, as a past thicker version. Though this thinner diameter can still improve the handling of the rope, we think that it is equally as important for people to look at the weight of a rope along with the diameter rather than focus on the diameter alone if they are looking to shed weight. Also, manufacturers do measure their diameters differently, and some ropes are even slightly oval-shaped and are therefore measured under slight tension to get the stated diameter. That's why you might have two ropes of the "same" diameter that feel completely different in hand and have different weights-per-gram. The chart below shows the different weights of the lines we tested.
Rope weights are measured in grams per meter increments since the variable length of climbing ropes changes the total weight. (A 70 m will usually always be heavier than a 50 m unless you're comparing a 7.8 mm half rope to a 10.5 mm big wall line.) As you can see, the 9.0 mm Sterling Fusion Nano IX and the 9.1 mm Beal Joker are the lightest of the bunch at 52 and 53 g/m. While this number alone might make your purchasing decision for you, considering the shorter lifespan of these thinner lines you may want to beef up a little bit more. The 9.5 mm Petzl Arial and Mammut Infinity are only a little heavier (58 g/m) but are easier to handle.
The other 9.5 mm line that we tested, the Maxim Pinnacle, actually weighs a bit more at 61 g/m. To put that in a more useful perspective, the 60 m Pinnacle weighs 6 ounces more than the Arial and Infinity. Is that enough to mean the difference between a send and falling off your high point again? It's hard to say — but in a world where every ounce counts and people cut calories to drop ounces off their bodies, shedding a few from your rope as well can't hurt. The Beal Booster III and BlueWater Ropes Lightning Pro also impressed us with their weight rating, as they are 61 g/m for a 9.7 mm line.
A climbing rope is typically the heaviest single piece of climbing equipment used. The difference between the 9.0 mm Fusions Nano IX and heaviest lines in this review, the Black Diamond 9.9mm and the Edelweiss Curve Unicore Supereverdry (64 g/m) amounts to 1.5 pounds. These differences add up even more when you get into longer 70 and 80 m climbing ropes, and when you're climbing longer pitches. Using a lightweight rope will keep your pack lighter on the approach and the difficulty of clipping down when you've led a mega pitch at Indian Creek and are hauling the weight of the entire rope for your desperate anchor clip. People are moving to even thinner climbing ropes (9.0-9.2 mm range) for these scenarios, but keep in mind that the lighter, skinnier ropes will not last as long as something thicker. This brings us to our final testing metric: durability.
When you throw down a chunk of change on an expensive piece of equipment, you want it to last a while. A climbing rope is the piece of climbing equipment that gets retired most often, and with good reason — it is both your lifeline and the most subject to wear. We evaluated durability in a few different ways. We took into account the diameter, as thicker ropes do tend to last longer than skinnier ones, the weave, how dirty the sheath got, and the state of the sheath after at least 60 pitches. Here's how we rated the various models on their durability.
While it's reasonable to assume that a 10.5 mm line would have greater abrasion resistance and a longer lifespan to a 9.0 mm one, the difference between some of the 9.9 and 9.5 mm lines in our test range did not seem quite as significant. The two models that stood out the most for durability, the Beal Booster III and Edelweiss Curve Unicore Supereverdry, were on the thicker side of our range though. The Curve was one of only two lines in this review to use a 1x1 weave, which tends to have a tighter weave than a 2x2 and therefore better abrasion resistance.
You'll often hear people commenting on how dry-treated ropes last longer than standard ones, and many people choose to purchase a line with that treatment regardless of whether they're using it in a wet environment or not. Mammut did some in-house testing on their lines and determined that their Dry treatment offers 50% more abrasion resistance than an untreated line, and their "Protect" (treated sheath only) delivers 40% more. We chose to test all dry treated ropes, except for the Black Diamond 9.9mm, which only comes in a standard finish. Then we compared sheath wear after our testing period, to see which ones were showing some fuzz and which looked brand new. The Maxim Pinnacle was another high scorer, and it was showing very minimal signs of wear, whereas the BlueWater Ropes Lightning Pro had some significant sheath wear in several locations on the line. This could have been due to one bad pitch where it ran over a sharp edge, or one climb where we whipped on a "sharp" carabiner, but considering that we used every line extensively and on a variety of types of rock and styles of climbing, the fact that this one showed the most wear resulted in us dropping its score considerably.
While a dry treatment may help prevent dirt and grime from working its way into the core, it can still accumulate on the surface of the rope! While we did evaluate for "dirtiness," we also accepted that all ropes get dirty, regardless if you're using a rope bag or not. You can wash your rope and get rid of some of that dirt, but it's a bit of a chore and not the easiest thing to do on a road trip or if you're living the dirtbag lifestyle. So we did appreciate the ropes that stayed cleaner longer. After testing was done we washed all the lines (front load washer, mild soap, indoor dry), and most took back on their brand new look, except for the Edelrid Boa Pro Dry. It seems as though the dirt was "glazed" onto this line, which can happen when the sheath heats up due to fast lowering through a hot belay device. These glazed sections can stiffen up and ultimately affect the handling and longevity of your rope.
Climbing ropes typically get retired due to sheath wear, so we also considered how much of the line was sheath vs. core. This spec can be a little misleading when comparing ropes of different weights. A heavier rope with less percentage of sheath can still have a thicker sheath than a lightweight rope with a higher percentage of sheath. But, when comparing ropes of similar weight, this spec can give you some idea of how thick the sheath is, and therefore how abrasion resistant it might be. The sheath proportion ranged from 35% to 42% in the 9.5 to 9.9mm lines that we tested, and all the way down to 29% in the Sterling Fusion Nano. There wasn't really a correlation that we could detect by the end of 60-80 pitches, but it's possible that further down the line, a 42% sheath model like the Mammut Infinity could last longer than the 35% Sterling Evolution Velocity. Once your sheath starts to wear out though, or if you have any concerns about the integrity of the core, your best option is to retire the rope, or at the very least cut the ends (though that creates a separate problem of having a line that is shorter than some routes). Too often we see people tying in to battered and frayed ends, which is a serious safety concern. Go ahead and read Black Diamond's quality control testing on this issue, and then go to your garage and retire your own offenders.
Deciding which climbing rope you're going to purchase is an important decision. It's also difficult to try them out first sometimes! Since the way a rope handles could influence your decision more than anything else, checking out your friends' ropes at the crag or gym could help give you an idea of what type of rope feels best to you. Hopefully, we have helped you fill in the blanks on the rest of your purchasing criteria, and that you can now make an informed decision on which one will suit your climbing style best, and keep you safe!
— Cam McKenzie Ring