Static Rope Elongation Percentage for Top-Rope Climbing

I am looking to get a static rope for top rope climbing. This may be super specific but is there a percentage of elongation I should be looking for to to allow for enough rope stretch for comfortable falls? Before you all say YGD, TR on low stretch ropes is fairly common and most gyms use a low stretch rope for their TR belays.

Thomas Worsham wrote: I am looking to get a static rope for top rope climbing. This may be super specific but is there a percentage of elongation I should be looking for to to allow for enough rope stretch for comfortable falls? Before you all say YGD, TR on low stretch ropes is fairly common and most gyms use a low stretch rope for their TR belays.

So you're confident you'll always be able to get your rope up there without leading on it? If it's TR only, really, then just find out what rope the gyms are using and buy that. 

In tech-speak, the rope you're wanting is a 'low-elongation rope' not a static rope. The static elongation (vs dynamic elongation) of the former that is commonly used in gyms is about 4% whereas the latter is <1.5%.

I'd imagine you have very specific and carefully considered reasons for needing an LE rope vs a dynamic that have been balanced with your experience level and that of the expected belayers/climbers. Whatever your rationale, don't go LE primarily for increased rope-life for general TR with novice/intermediates. LE removes a layer of safety and comfort while requiring extra (no-slack) diligence and perhaps your vigilant supervision of others...somewhat contra to a carefree TR session with the gang.

I don't think a specific stretch is what you want to look for, but a specific cert. EN 1891 is going to tell you that it is low stretch and that it has been tested for low factor falls. It also tells you that when it catches you that you aren't going to be in the market for new kidneys.
Full dynamic is not always the best choice for style or safety. Full static can mess you up on a surprisingly short fall with nominal slack alone.

Thomas Worsham wrote: I am looking to get a static rope for top rope climbing. This may be super specific but is there a percentage of elongation I should be looking for to to allow for enough rope stretch for comfortable falls? Before you all say YGD, TR on low stretch ropes is fairly common and most gyms use a low stretch rope for their TR belays.

Go buy a spool of "gym rope", the main manufacturers all make a version. 

Literally any static rope will work great for toprope only, don't overthink it.​​​​

Sam Skovgaard wrote: Literally any static rope will work great for toprope only, don't overthink it.

Please disregard this advice. Even short TR falls on static rope are at  best described as unpleasant.

amarius wrote:

Please disregard this advice. Even short TR falls on static rope are at  best described as unpleasant.

Hogwash.  The fall factor of even a big toprope fall would be in the range of 0.04 to 0.08 (calculated for a 2 meter fall, depends on how high on the route you fall).

Sam, I think it is more of aspect of impact force in real world applications. That little bit of stretch is a big factor. Also, if someone is rapping a top rope set up, it's not unthinkable that fairly high FF ratios can happen. There is a reason that ropes <1.5% are not appropriate for life and safety with a direct connection.

Carson Mc wrote:...Also, if someone is rapping a top rope set up, it's not unthinkable that fairly high FF ratios can happen...

What?

Sam Skovgaard wrote: Literally any static rope will work great for toprope only, don't overthink it.

I’d also disregard this advice as top roping on sub 1% stretch ropes can definitely be a bit painful.  I know this from personal experience and top rope on static ropes all the time.  Get a low elongation rope, 4% or so feels way better.

Mikey Schaefer wrote:

I’d also disregard this advice as top roping on sub 1% stretch ropes can definitely be a bit painful.  I know this from personal experience and top rope on static ropes all the time.  Get a low elongation rope, 4% or so feels way better.

Listen to this guy. He knows what he's talking about.

I TR solo extensively on a 3.8% elongation rope and haven't felt it was too jarring.  I am usually more surprised I fell (Hello!) than the catch.

I use Petzl Microtrax, and a 9mm (3/8") static.

Buck Rio wrote: I TR solo extensively on a 3.8% elongation rope and haven't felt it was too jarring.  I am usually more surprised I fell (Hello!) than the catch.

I use Petzl Microtrax, and a 9mm (3/8") static.

Sounds like one of the Bluewater BWII ropes?

I have used that as a single rape line with a dynamic rope for a belay when teaching beginners. The low stretch is easier for them to get started over the edge.

while in Alaska with a special unit we trained all the time with 7/16" static rope in many environments. I can tell you many things can be done with them. Here is the catch. (pun) If you are not very careful and have a very detailed system in place, someone will get hurt. In later 80's we started using a lot more dynamic rope. What a difference. The margin for error went way up. A small slip into a crevasse with static rope on a swiss seat with a 70lb pack and you better pray you are wearing your swiss seat right!  Upside down trying to right yourself and rig a pursic sucks. Shock load harsh, and can be painful.
 As with all climbing equipment there is a place and time for it. You need to carefully weight what you are doing with it and why. It's human nature to see right off why to use a piece of equipment. It's not most people's nature to think about why not or the detailed thought of how can this go bad on me. I was always taught to think of worse case and plan off that. Having said that I again say static has its places, hauling, top rope solo, hand lines etc.
 As for top rope, yes it can be used but at what risk? Also remember shock load to belayer and anchors. the risk of a single mistake could be very serious. Or even worse someone mistakenly leading on it. For these risk you have to answer to what advantage is this rope to me? 

Dave Olsen wrote:

Sounds like one of the Bluewater BWII ropes?

I have used that as a single rape line with a dynamic rope for a belay when teaching beginners. The low stretch is easier for them to get started over the edge.

I bought it from Rock n' Rescue, New England KM III.  We'll see how robust it is this spring.

9.5mm static elongation is 3.6% at 300 pounds

Sam Skovgaard wrote:

Hogwash.  The fall factor of even a big toprope fall would be in the range of 0.04 to 0.08 (calculated for a 2 meter fall, depends on how high on the route you fall).

Thanks for the math.  Not disagreeing with your numbers.  They are not exactly relevant here.  Small falls on a static rope can be quite jarring and uncomfortable.  Much more so than small lead falls on dynamic rope.  

There is really no excuse for TR falls generating any kind of fall factor. And most static ropes have some give to them. A gym rope, for comparison, has about 8%-9% static elongation, compared to 3.6% for a static rope.  There are low stretch polyester ropes out there (<1%), but that isn't what we are talking about.  

If all you are going to use a rope for is TR and TR solo, a static line is perfectly viable. So is a dynamic rope, that could also be used for leading.  For beginners, the sponginess of a dynamic rope can be disconcerting at first, since when they go to slump on the rope it gives the feeling that they are going to fall.

Buck Rio wrote: And most static ropes have some give to them.

Yes, they do - 1% for canyoneering ropes to ~4% semi-static gym TR ropes.
If someone is looking for static-y rope for solo TR-ing outside my recommendation would be to  cough money for semi-static gym TR rope instead of getting anything less stretchy.

Not to mention the rope slipping through the anchor during a fall will drastically reduce fall factor, it isn't like taking a daisy fall for example.

Some good info in this video from a guy who knows his sh:t. The drop test simulates a fall on a CRAZY loose TR (fall factor .33) - with a no-slip belay AND a weight greater than most climbers. The impact isn't any more jarring than a normal lead fall.

How ridiculous is a .33 toprope fall factor? Imagine you're toproping an 80 ft route. Anchor at the top, belayer at the bottom. We're looking at a situation where you reach the anchor only to realize that the belayer took in NO ROPE for the last 40 feet, and then you fall off.

https://youtu.be/9I5FhE7sp_U