How to Fit (& Find) The Right Climbing Rope

Gear like harnesses and helmets have specific fit preferences, but how do you fit a rope? Finding the right rope comes down to a few considerations including your belay device, experience level, route location (indoors, outdoors, if it’s outside the season), along with the height of the walls you’re climbing. We’ll dive into each of these in more details below.

Belay Device

This is the only time where your rope has to fit. Each belay device has a specific range of rope diameters it will accept – and this rope range will always be printed on the belay device. Sometimes the device will have multiple rope ranges based on the rope type (single, twin, or double ropes).

Occasionally, on a product page you might see two single rope ranges. This is when a brand has a recommended range for the best experience and also a maximum range of what ropes you can safety use (but perhaps the experience will be less ideal when you are at the greater limits).

If your rope is bigger than the rope range on the belay device, it is not necessarily a safety concern, but the rope will feel slower and harder to go through the device. If your rope is smaller than the rope recommendation then it may present a safety issue as the rope may not engage the device correctly. The rope could slip or flip in the belay device causing the device to malfunction.

It’s worth noting that over time ropes get fatter as they start to fuzz. Sometimes ropes can go up .5mm from their original size. This means that over time a 9.8mm rope could act like a 10.3mm rope. This is also why gym ropes can sometimes feel harder to handle: they start out with a large diameter and then they fuzz into an even larger diameter – often one that is beyond most belay device’s recommend rope range.

Climber Experience

Most gyms provide ropes that are 10mm – 10.5mm in diameter. This creates a certain handling experience that can be slower as the fat rope takes up more space and adds more friction as it moves through the belay device. This also means that climbers who only have experience in the gym may at first find a skinnier rope to be harder to handle because a skinny rope can act more slippery and will move through the belay device quicker than expected.

We recommend that climbers buy their first rope around the 9.8mm range. This diameter works smoothly in the vast majority of belay devices. It also is a little lighter to carry than 10mm+ ropes. For general durability and a lot of top-roping and hanging, a 10mm or 10.2mm rope can also be great.

We hesitate to recommend ropes smaller than 9.7mm ropes to new climbers as not only are these ropes significantly skinnier than gym ropes, but if the rope has a dry treatment, that protective layer will exacerbate the slippery issues and can be much harder to control. The main benefit to a skinnier rope is lighter weight. So if you’re not hiking very far to the climb, the larger diameter ropes will not have any significant disadvantages.

Route Location

The main reason the route location makes a difference is because different areas have different heights for climbs. For example, indoors, a 30m or 40m rope is almost always sufficient (check with your gym!). If you’re only climbing indoors, there is no need to spend more money for a longer rope.

Some outdoor locations are also very short, like Reimers Ranch crag outside of Austin, TX, where the routes are never higher than 15m and most are closer to 9m.

Otherwise, if you plan to climb outdoors (and travel further than a short local crag), a 60m is considered a standard length. That said, there are some climbing areas where a 70m is necessary for some newer climbs, like in Ten Sleep, WY. 80m ropes are often reserved for specialty one-of-a-kind type climbs, it is extremely rare to need a rope this long.

Gear Geek Tip: Most 60m ropes are not exactly 60m. Manufacturers usually make them slightly longer to account for any shrinkage. Within this extra length some rope brands produce ropes that are longer than other rope brands. This means if the climbers who put up the route, estimated distances by using the full length of their rope, you could find your 60m rope only barely reaches the rappel station (or ground) when weighted. We’ve experienced this most often climbing at Red Rocks, NV. Just another reason to always tie knots at the end of your rope — so you don’t rappel off the end (the most common climbing accident, it has resulted in numerous fatalities over the years).

Bottom line, a 60m rope is a good bet if you plan to climb outdoors throughout the US. If you only climb indoors, verify the height of your local gyms walls. If you never want to be limited by the length of an outdoor route, get a 70m – though we recommend a 70m more often as a second rope, so you don’t have to drag around an extra 10m on the majority of the climbs.