Ropes aren’t cheap, and they are often the main investment required to get your climbing hobby up off the ground. Due to the inherent risks surrounding climbing, climbing companies have developed and improved specific ropes for the sport. Modern climbing ropes contain many features, but one of the most basic decisions is regarding the thickness. If you’re trusting your life to a piece of rope, how thick does it need to be? We will look through the best diameter rope for climbing below, as well as other important factors to consider.
The best diameter rope for most climbers is between 9.4. and 9.7mm because it is strong and abrasion-resistant, but not extremely heavy. Beginners should generally start with something thicker, such as a 10.2mm because it feels trustworthy and strong. There are advantages to using different diameters for specific types of climbing. Some climbers have a garage (or a van!) full of different diameters and styles of ropes for use in various situations.
Pay attention to the ropes that you use when you’re out climbing. You’ll usually see pretty thick ropes in the gym, and thinner ropes in the outdoors. Here are some tips to help you pick out the best diameter of rope for your needs:
If you’re interested in the best climbing gear for outdoor climbing, click here.
Climbing Rope Thickness
Thicker Ropes (9.6mm to 10.7mm)
A thicker rope means you’ll rappel slower (more friction). They are easier for most people to handle, and sit more securely in belay devices. Thicker ropes are also a little bit safer around sharp edges, and are more abrasion-resistant than thin ropes. The main disadvantage to thicker climbing ropes is the added weight, both in the rope bag on the hike in, and dragging down the lead climber between protection. For this reason, a lot of people start out with a thick rope, and then buy a thinner rope as they get more into climbing. Thick ropes are designed to take a beating, and are very good gym ropes. Pay attention the next time you are at a climbing gym, and you’ll notice that they use very thick ropes. Thicker ropes last a lot longer and are very durable.
Thinner ropes (8.9mm to 9.5mm)
Thinner ropes are faster. I have a 9mm dynamic canyoneering rope that we named ‘twin lasers,’ and it will burn a hole in your hand if you try to use it without gloves on! Thinner ropes are generally lighter weight, and usually have more stretch. They wear out more quickly, and provide less friction on your gear. Thinner ropes can feel ‘slippery,’ and don’t always fit snugly in belay devices. Be sure to practice a little bit with your partner before trying out a smaller-diameter rope on the rock.
Thickness does not necessarily equate to strength, as several manufacturers have developed ways to compress the inner fibers to bring the same strength into smaller sheaths.
Again, it probably doesn’t really matter what diameter rope you have. You’ll probably be most comfortable with the diameter climbing rope you learned on, and they pretty much all have the same strength. The best diameter rope for climbing will depend on your individual preferences.
More on Climbing Ropes
It’s important to keep an eye on several other features when purchasing a rope-
Most climbing routes can be done with a 60m rope. On most multi-pitch routes 60m will get you to the anchors on each pitch. There’s a fairly recent trend towards 70m ropes however, and it’s important to check with locals to see what how long the routes are. Different areas have differing standards.
A 70m can be nice over the long run as well, because a longer rope makes it so you can trim off the ends- the ends of the rope are the most abused as they often lay in the dirt and catch lead falls. Many climbers will have a shorter 35m to 50m rope for gym climbing where the walls aren’t as high.
The weight of a rope doesn’t really matter for top rope and gym climbing, which is why you’ll see thicker, heavier ropes at gyms. Climbers who hike their gear into remote crags, or who do a lot of long pitch routes look for lighter ropes (and generally thinner ones).
With 50 to 70 meters of heavy rope dragging a lead climber down, every gram of weight counts. Rope manufacturers measure rope weight in grams per meter, so just multiply the number by the length of the rope to get the full rope weight.
Static v. Dynamic
Climbing Ropes should be Dynamic. The rope has a little bit of ‘give’ as to provide a cushion to a falling climber, to soften the impact on the protection, and to ensure that a jerk on the rope doesn’t compromise its integrity. If you really want to immerse yourself in rope specifications, ropes go off of static and dynamic elongation, measuring how much the rope stretches in different situations.
Static elongation is a measure of rope stretch with a constant 80kg force applied, and dynamic elongation is the percent the rope stretches when a weight drops. Static elongation should be at 10%, while dynamic elongation can be between 10 and 40%, depending on climber preference. Be careful with ropes with a higher dynamic elongation- even though they provide more cushion on a fall, there’s also a greater chance of hitting the deck with the rope stretch.
Static ropes are generally used for rappelling, caving, and canyoneering, as well as for hauling loads. All ropes stretch a little bit, but these aren’t designed to softly catch a falling climber, and could be damaged with a heavy jerk. The low elongation of static ropes makes it so they work well with ascenders.
Ropes are certified by the International Climbing and Mountaineering Federation (UIAA). The test involves repeatedly dropping a weight on the rope until it breaks. Ropes should be rated to withstand at least 5 test falls (note: the falls used in the tests are much more severe than any falls that you would regularly take climbing). Ropes use several other safety ratings as well, in reference to the elongation under static and dynamic duress, and sheath slippage.
There are a few other things to look for when buying a rope. One of our favorite features included in most new ropes is a middle mark. Knowing where the middle of the rope is can be very useful for all rope sports. In rappelling, caving, and canyoneering, a middle mark helps guarantee you won’t slide off one end of the rope when rappelling both strands of the rope or tandem rappelling. For climbing, the middle mark is a sure sign that you need to find an anchor and head back down (unless you’re doing a multi-pitch route).
My first climbing rope didn’t come with one, so I added one with permanent marker. The middle mark has saved me on several occasions! Middle marks are usually about a meter-long black section, though some brands have started completely changing the material in only the middle section, with bright colors and patterns. A few ropes have a different material in the middle so the belayer’s hands feel it before it goes through the belay device.
Another option is a bi-patterned, or bi-sheathed rope, where each half of the rope is a different color. Unfortunately these are significantly more expensive. There are lots of ways of doing it, but the bottom line is that a middle mark can save you from a very precarious situation. Some ropes have end markings as well, to help catch the belayer’s attention. Don’t forget to close the system and knot the end of your rope!
Another thing to look for in ropes is a dry treatment. A wet climbing rope loses up to 70% of its strength when absorbing a fall on lead. Wet ropes are still okay to rappel on (they don’t lose their static strength), but even a splash of water on a regular rope can weaken its strength significantly as the fibers inside absorb water. Dry treatment coats each of the inside fibers so they won’t absorb water. Still, even with dry treatment, a rope can lose up to 40% of its integrity when wet. As long as a fall isn’t taken on the rope when wet, it can be dried out later and it will return to its normal strength.
I tend to gravitate towards bright and flashy colors for my climbing gear (my main climbing rope is electric blue and pink, and my main canyoneering rope is electric yellow) because I like for it to pop out in pictures, but a lot of people prefer more earthy colors like black, brown, and green. Fortunately, climbing ropes come in every color of the rainbow so you can find whatever you like.
Buying a Rope
The most important features to consider when buying a rope are the length and diameter. For a great all-around versatile rope, we recommend a 60m 9.7mm rope. The best diameter rope for climbing does depend on your individual needs. Feel it in your hands, and make sure you feel good about the rigidity and bulkiness, and then take it out and break it in!