If you’re not sure what the difference is, you want a dynamic rope. Dynamic ropes are designed to act like springs, meaning when you fall the rope stretches to cushion your fall. This is good as a fall from even 3 feet on a static rope will generate enough force to seriously injure you.
- Top Roping
- Lead Climbing
Static ropes are generally thicker and more resistant to cuts. They should never be used when there is any possibility of falling on them from any height. However, they work well for rappelling, fixed lines, rescue situations or pulling your friend’s car out of a ditch after he went around that corner too fast.
- Towing a car
If you’re not sure what these ratings mean, you want a single rope. They work well for top roping, sport and trad climbing. They are thicker ropes, generally from 10.5 mm all the way down to 9.1 mm.
- Less complicated
Also known as Half ropes, these are thinner and designed to be used as pairs. They’re more expensive then single ropes--you have to buy 2 ropes! When leading you alternate the rope used for each placement. The benefits of this complexity come when a route wanders (less rope drag), your gear is sketchy (less impact force), or there is a possibility of decking (you don’t pull out slack from the rope connected to your last piece of gear). They’re also handy if you’re climbing in a party of 3 on a multiptich route as you can bring both seconds up at the same time, one on each strand. Longer rappels are also handy and you don’t have to thread half the rope through the anchor.
Twin ropes are similar to half ropes, but instead of alternating clips, both strands are clipped into each piece of protection. They are more commonly used in ice climbing, where they add redundancy against a single strand being cut.
Longer is better, especially if you’re not the one carrying the rope, right?
If you’re buying just one rope for single or multipitch climbing, you want 70 meters. Old crusty trad climbers will tell you 50 meters used to be enough for anyone and this might still hold true for alpine climbing. For rock climbing, a 60m rope will get you up most routes and springing the extra $30 for a 70m will let you go almost anywhere.
If you’re Chris Sharma and people are lining up to give you free ropes, pick a 9.1mm.
For rest of us, rope diameter comes down to durability vs weight. If you’ll only be top roping, something in the 10 mm range will last a long time against the abrasion encountered rubbing against the rock. If you’re lead climbing, you’ll probably want something between 9.7 mm and 10.1 mm.
A thinner rope, especially one with a dry coating, will fly through a belay devise so be careful! Also note that the GriGri2 works best with ropes between 9.4 mm and 10.3 mm and will not work with ropes thinner than 8.9mm.
If you're placing your own protection as you climb, you'll want to pay attention to the impact force. This is the peak force measured during the first 1.71 factor fall of the UIAA drop test.
Impact force is related to elongation and sheath slippage. Lower impact force is better for trad, but the rope will stretch more (higher chance of decking) and the sheath is more prone to slip from the core resulting in bunching at the ends of the rope.
For a rope to be certified by the UIAA, it most undergo a very strenuous fall test. For a single rope, an 80kg (176 lbs) mass is dropped repeatedly until the rope breaks.
Here’s the scenario the test tries to replicate:
You’re starting to lead the second pitch of a climb with your partner anchored into two bolts. As you start climbing, you clip into a quickdraw on one of the anchor bolts. You then climb up 7.5’ without placing any pro and then fall past your partner. After taking into account the slack in the belay, you have fallen 16’ with only 9’ of rope out. Now repeat this fall every 5 minutes until the rope breaks.
Most of the falls on your rope will be much less severe with more time for your rope to rest. This means you don’t need to retire your rope after 5-10 falls, but you should always check it for damage. You'll also want to switch the end you’re leading on if the fall is severe enough.
When a rope gets wet it becomes heavy and also loses some of its strength. To combat this, a rope can be treated by a chemical process that makes the fibers repel water and dirt. Manufacturers all have different names for this process, but they treat either the rope core, the sheath, or both.
In addition to keeping the rope from getting wet, the dry process can also alter the characteristics of the rope. The reduced friction between the fibers can increase the number of UIAA falls and decrease the impact force.
Finding the midway point of your rope can be crucial during long rappels. Bi-pattern ropes change the weave pattern in the middle of your rope making it trivially easy to spot the midway point. The only drawbacks to this are cost and your rope may be longer on one end if you have to cut off part of the rope on one end.
Another common method of marking the midway point is a black mark. Beal sells special rope-safe ink as a DIY solution if your rope did not come with a midway mark or if it has faded.