Gri-Gri and 13mm

I was wondering... why is the Gri-Gri only 10-11 mm? It seems to work well with my 13mm arbo rope, what am I missing? I haven't tried anything at any height yet, but at low levels, it grabs and decends like it should. What gives? If you have any exp. with this, let me know... or if you know what Petzl has to say about it. Thanks!

mateo

I'm guessing 10-11mm is the sweet spot for static line. Someone (Oldtimer?) on a TCC thread mentioned that static line over 11mm is too stiff to run through smoothly. The flexibility of your arborist rope might be extending the range of the Gri-Gri. If it runs through smoothly without abrading the rope then you're good to go. It's a fairly simple and bullet-proof device.

I havbe done the same with mine. I cut my lanyard with a chainsaw and discarded the nicked rope and replaced it with a 1/2" rope as a spare lanyard being I bought a wire core one.

You could just go to your nearest rock climbing store they have the rope for it that you need. I wouldn't use the grillion with a larger rope though for a life support just as a postitioner.

I'll do a low test with my Gri-Gri on 1/2" arborist line and see what it's like. Obviously Petzl would rather you use the ID which is rated for thicker line.

Climber020, I think is Mateo is referring to using the Gri-Gri for rappelling as opposed to on a lanyard (Grillon).

Oh I see. but it is the same device just 2 different uses and names.

I use the Grigri regularly with 7/16 in (about 11mm) Arborist (Sportline) rope and there is not significant problems. My ropes are fairly flexible and run well in the Grigri. I also have a KMIII Static Kernmantle Rope from New England (11mm for SRT ) that is stiff and it is more difficult to make it move across the Grigri. I think that the flexibility of the rope is more critical than the width.
Disclaimer: This is all my observation and the Manufacturer has done laboratory tests that probably demonstrated that I am completely wrong. The rock climbing ropes that I have seen are hard to bend (not easy to knot) so that is where I get my observation from.

Obviously if the rope is so large that it does not physically fit inside the Grigri them you should not force it and try to make it work because it will probably not work regardless of how much you try.

On the smaller diameter ropes the Grigri may not hold tight and you will have to hold it similarly to what you would have to do with a regular figure 8 descender. Other climbers w/ with more experience with ropes may chime in w/ their personal point of view I am sure.

Using rope that is a larger diameter than the device is bujilt for changes the cam action. Since cams are curved levers you can think of this as chainging the lever length or position of the fulcrum. either way, the whole mechanical system changes.

Do NOT use gear with rope that it is not built for. Trust the engineers and testing facilities.

Well I did some low level testing today, and then I went a little higher (50ft) and all worked well on my XTC line with the yo-yo setup -- ascending and decending. It doesn't seem to slide through any quicker or slower... what it could be (and I haven't tested yet) is that with a larger diameter rope the auto belay doesn't work as well i.e. the rope feed at slow speeds doesn't work with larger ropes. As far as everything else is concerned it works fine. I'll let you know if I find anything else out.

mateo