Selecting Appropriate Climbing Rope Size for Safety and Efficiency

Picking the perfect rock climbing rope is no walk in the park. With multiple factors at play, it can be a headache figuring out what's best for you. Here's a lowdown on rope diameter, handling, elongation, durability, and more to help you make an informed decision.

Mind the Gap: Rope Diameter and Its Best Uses

Rope diameter plays a crucial role in performance, to the point that many climbers have different ropes for various pursuits. For instance, we've got a sturdy workhorse for top-roping, a mid-diameter rope for projecting, a slim line for the alpine, an aged shaggy rope for the gym, and twin ropes for a party of three. Let's delve into the best rope diameters for each activity:

Slim and Trim: Alpine Climbing, Redpointing, Multi-Pitch (8.5mm-9.3mm)

Also known as "skinny ropes," these ropes are mainly used in alpine climbing and multi-pitch scenarios, where every ounce matters. For example, the 8.5-millimeter Beal Opera weighs just 48 grams per meter, making it significantly lighter than a thicker rope that weighs 60+ grams per meter. However, skinny ropes require skilled belaying and more care than ropes in thecategories below. Plus, they're prone to being less durable. If you plan on doing a lot of top-roping or taking repeated falls while projecting a sport route, a thicker rope would be a safer option. But if you'll be tackling monumental heights in a day, covering long approaches, or slaying your project, a slender, lightweight rope can make all the difference. Our current favorite skinny ropes are the Beal Opera (8.5mm) and Edelrid Swift Eco Dry (8.9 mm).

Versatile and Mighty: Cragging, Top-Roping, Multi-Pitch (9.4mm-9.7mm)

Ropes in the mid-9mm range, or medium-diameter ropes, are the most adaptable option for the majority of climbers. For those just starting out in the sport and looking for one rope for both cragging and multi-pitch, this is our recommendation. A medium-diameter rope strikes a great balance between durability and weight, providing moderate stretch for bouncy lead falls without sacrificing much for top-roping. Plus, a rope in this range boasts better handling than a skinny rope and greater durability. Two of our favorite medium-diameter ropes are the Mammut Crag Dry (9.5mm) and BlueWater Lightning Pro Double Dry (9.7mm).

The Heavyweights: Cragging, Top-Roping, Gym (9.8mm-10.2mm)

We can't sugarcoat it: We're not big fans of thick ropes. Ropes that clock in at 9.8 millimeters and wider in diameter are becoming increasingly obsolete—and for good reason. Medium-diameter ropes now offer similar levels of durability at lower weights and similar price points. Furthermore, thick ropes don't perform well in belay devices—a lightly used 9.8-millimeter rope might even be difficult to move through a Grigri. Thicker ropes are still useful in certain situations, though. If you're consistently top-roping in areas with sharp rock, climbing in the gym, or on a tight budget, a fat rope makes for a solid workhorse. Even so, 10.2 millimeters is probably about as thick as you would ever want to go—unless you're using it for route development or a lot of ascending. Two high-performing thick ropes are the Sterling Velocity Xeros Dry (9.8mm) and Mammut Crag Classic (both 9.8mm).

Thicker is Better, Right? Not Always.

It's easy to get caught up in the "light is right" movement in climbing and other outdoor activities. But the truth is, beginners don't need the latest and greatest gear. In fact, employing cutting-edge equipment before mastering basic skills can be downright dangerous. Thin ropes have their place in alpinism and redpointing, but for all other climbing purposes, they do more harm than good. So, while we're not trying to dissuade experienced climbers—and we personally frequently climb using sub-9-millimeter ropes—we recommend sticking within the mid-9-millimeter range and above for the everyday climber.

Two's a Company: Half Ropes and Twin Ropes

Most climbers in the United States climb on a single rope, but double ropes—or twin ropes—are sometimes the most convenient or safest option. We recommend double ropes for ice climbing, climbing as a party of three, routes that wander a great deal to mitigate rope drag, and multi-pitch climbing when two ropes are required to rappel.

Our Top Climbing Rope Picks

After over 15 years of climbing experience, we've had the opportunity to test countless climbing ropes in a variety of settings worldwide. Here’s a selection of our favorites organized by activity:

All-Around Amazing: Mammut 9.5 Crag Dry

Budget-Friendly: Mammut Crag We Care Classic 9.5

Redpoint Rockstar: Edelrid Swift Eco Dry

Cragging Champion: Sterling Velocity Xeros Dry

Ultra-light for Alpine Climbing: Beal Opera Golden Dry

For a comprehensive round-up of the top ropes for every climber, check out our article on the best rock climbing ropes.

In the realm of various climbing pursuits, it's essential to consider the appropriate rope diameter for optimal performance. For instance, alpine climbing, redpointing, and multi-pitch scenarios benefit from slim ropes (8.5mm-9.3mm), such as the Beal Opera or Edelrid Swift Eco Dry, due to their lightweight nature, even though they require skilled belaying and may not be as durable.

On the other hand, for beginners and those seeking an adaptable option for cragging, top-roping, and multi-pitch, mid-diameter ropes (9.4mm-9.7mm) like the Mammut Crag Dry or BlueWater Lightning Pro Double Dry provide a balance between durability and weight, making them a popular choice.