How often do you replace webbing/cord?

A couple years back during one of the Boulder Beer Nights @ the Dark Horse, I got to talking with Malcolm about frequency of replacing webbing and cord. He stated that he usually does a clean rotation of runners etc every year (correct me if my memory is off on that, Mal). That burr has been sitting in my thoughts ever since, and I've replaced some soft goods more frequently because of it (though, admittedly, there are still a couple runners/cords/etc in my rack that are pretty damn old).

While surfing the web for accessory cord and knot failure info yesterday, I came across a writeup by Todd Vogel from 2002 regarding tests he did with BlueWater on different knots, webbing, etc and it included info on the reduced strength of 7mm BW cord he tested that was just 18months old [edit to add: these were well used cords, but it good condition] .... result "failed consistently at 60% of the same cord in new condition." Oooof. Which got me to thinking about my 3yr old cordalette, and the limiter knots I put in it when I use it as a sliding-x (thereby further reducing the strength), etc, etc. Time to replace.

So the question is, how often do you replace your webbing and cord? And might the writeup from this set of tests possibly get you to increase that frequency?

outdoorlink.org/ol/files/tr…

when and if i can afford it, would be my reply. i use mostly nylon slings, the three skinny dyneema that i do have should probably get retired.

I read an article a few years ago stating that webbing, if kept out of the elements and direct sunlight, retains its strength for many years. The author said that if webbing degraded that quickly, we'd need to also get the seat belts in our cars replaced every few years. If it's supple, not stiff, and not torn or abraded, they said keep using it.

Good question, would like to have someone 'in the know' comment here.

Erik, you bring up a good topic. Considering my sport draws are nearing 8-10 years old, I have been recently thinking about the wisdom of replacing them. However, while the write up from Todd Vogel is nice, it really lacks enough detail to be particularly useful.

I think some (not all) of the problems that you should be concerned with have to do with how various types of cord respond to the number of bending cycles (i.e. tying knots). A while back, I posted some highlights from testing that was done on a variety of brands and types of cord. You can see the highlights here:

mountainproject.com/v/j_alb…

The full test results and write up is here:

xmission.com/~tmoyer/testin…

One of the scarier features of this test was in regards to a product that I used to use: Sterling Vectran. This stuff seemed great at the time; it was 5.5 mm so it was light, and unlike many other 5.5 mm cords, it was very supple. Unfortunately, after only a small number of bending cycles, the Vectran's strength was drastically reduced. I ended up moving to 7 mm Sterling cord for my belay cords because it didn't seem to be effected nearly as much by the tying and untying of knots.

Neither of the above tests really answer my main question, that is, how long should I consider the lifetime of sewn slings to be? Anyone got any info on this?

Hansel wrote:I read an article a few years ago stating that webbing, if kept out of the elements and direct sunlight, retains its strength for many years. The author said that if webbing degraded that quickly, we'd need to also get the seat belts in our cars replaced every few years. If it's supple, not stiff, and not torn or abraded, they said keep using it. Good question, would like to have someone 'in the know' comment here.

I don't remember where this came from, but I know that I read the same somewhere. This was more or less the concept that I have been using to judge whether to retire slings. Does anyone have info on who did these tests? The results would help answer some of the above questions from the OP.

I agree it would be helpful to see the raw data behind Vogel's tests, but I'm guessing he's got it and just decided to put out a summary instead that the masses could understand. Still, the nerd in me would love to dig deeper into those findings.

I remember reading Tom Moyer's piece on high strength cord a couple years bac. I think the best thing that came from those round of tests was, as J.Albers mentioned, the bending cycle tests, because that puts things into more real world applications.

So here's another study done on environmental contaminants on ropes (interesting read on its own). I think it provides some insight as to why regularly used climbing nylon in cords and webbing cannot be compared to samples that have just been exposed to UV or aged samples hanging on a wall (or seatbelts for that matter), since the negative effect of dirt and water on the strength of the material is significant (statistically speaking). It's interesting to read that portions of a rope become permanently plasticized from getting soaked... even after drying... and I'm guessing the same holds true for 7mm cord and nylon webbing.

http://personal.strath.ac.uk/andrew.mclaren/MatthewSmith2005.pdf

Did anyone throw this one into the mix yet?

bd gym draw test

once a year-ish for my double length dyneemas.

about 3-4 years for my nylon cord that doesn't get gutted for v-threads.

well i'm screwed half my slings date back to (1997) still and the other half(2002).. but my rope is new and so is my harness(2005). to make matters better i've been climbin on the same top rope set up for a year
give or take. my cord is 7MM but about 6.5 years old time to replace.
good luck longs..

I normally replace my slings (bluewater spectras) every other year, cycling half each year. I wouldn't even think twice about keeping them for 3-5 yrs but they're inexpensive to replace and I prefer the peace of mind.
Recently been cycling in BD dynex and mammut dyneema slings and those will probably be cycled out on a yearly basis. They just don't seem to hold up to the same kind of abuse as my spectras.

Cordalettes never make it past a year with me, often they end up replacing old tat where I find it, so that's never been a concern.

Dogbones on the sport draws are done about every 3-4 yrs.

Supra