UKC

So I've just measured my 80m rope to discover it is almost exactly 72m long. So I measured my 60m to discover it's 54.5m long. Have I gone mad and they are actually a 70 and a 50!?!

I always thought ropes were slightly longer than stated. They are both well used and thicker than they used to be (shrunk?) and I did measure multiple times. Does anyone know the standard manufacturer length for an 80 (or any length) or if there is one. Surely this must be an error on my part?

In reply to SimTee:

A colleague did a lot of research into this about 10 years ago and ropes across all manufacturers he looked at were quite a bit longer than specification when first bought.

However I'm pretty sure thinking back to static caving ropes that once washed they do tend to contract/shrink to some extent. 

In reply to SimTee:

Consider the possibility that the ropes are short due to the core untwisting over years of use and making the rope thicker but effectively shorter - happens to climbing wall ropes all the time with repeated use - they start off about 10mm diameter and end up so fat it's sometimes a struggle to get them through a belay device... and they are also shorter....

In reply to Jenny C:

On a related note...

(If you don't care about the exact length) Is there any good reason to wet and shrink your static rope before you use it?

In reply to gravy:

For caving having to abseil and jummar up ropes repeatedly it's best if they have been soaked, this prevents sheath slippage and a little bit of reduced stretch/ bounce. It also helps tighten the fibers a bit so helping stop the ingress of mud/particles which can abraid the fibres as the rope is repeatedly stretched.

Not uncommon to loose 10-15% on initial soaking and drying, you wouldn't want to be short whilst rigging a pitch on your "shop bought 60m" when after a few wettings its nearer 50m!

In reply to SimTee:

Is there a good way to measure the length of my rope? 

In reply to SimTee:

Both ropes are approximately 10% shorter than stated.
Are you sure that your measurement/metrology method is correct?

In reply to FactorXXX: if you hang them vertically, (ie like any situation where their length is important) they will be longer because of stretch under their own weight. 

In reply to gravy:

Most have caving ropes of different lengths, labelled on the ends etc.. so if you rig a cave, with pitches of say 15m, 9m, 30m, 20m... you don't take 4 x 50m ropes. But it's wise not to label until you've used them a few times and always allow a metre or two extra for shrinkage and knots, to avoid disappointment. 

In reply to SimTee:

A mate and I once ordered a twin pack of 60m ropes on a cheap deal from work (roca I think, it was a while ago). We went climbing about a week after getting them and there was about 6m difference between them, mine (lucky me) was about 63m and his 57m.

Rope length should be measured by the manufacture according to UIAA standard; See chapter 3.4: https://theuiaa.org/documents/safety-standards/101_UIAA_Ropes_V9_2019.pdf

Which is definitely not horizontal on the floor without load. 

Because there are more variables; most brands have a few percentage of variation, where the minimum length should not be shorter than the length measured using the UIAA method.  

In reply to SimTee:

Just like people, ropes get a little bit shorter and a little bit fatter as they age

In reply to CantClimbTom:

and weaker too!

In reply to kevin stephens:

also dirtier and more kinky...

In reply to FactorXXX:

... and stiffer and less dynamic.

In reply to SimTee:

Have you ever washed them ?

In reply to CantClimbTom:

I'm a frayed knot

In reply to tjin:

Wow, That's not the most intuitive way to measure a rope length!

and it would make measuring long stretchy ropes very difficult.

In reply to Dan Arkle:

We don't " measure" anything intuitively, we use standardised systems, for ropes you can pick from CI 1500-02, ISO 2307;2005 or ASTM 4268 depending on the country or application.