Understanding Climbing Fall Forces on Small Gear

Unfortunately the phenomenon that the DAV saw increased braking with the 8.9 rope is not to be relied on, it very much depends on the belay device and the karabiner to allow the rope to twist in the plate, most modern plates don´t seem to show this effect at all.
If you make a plate to take full advantage of the jamming effect the rope twisting is unbelievable!

Jim Titt wrote:Unfortunately the phenomenon that the DAV saw increased braking with the 8.9 rope is not to be relied on, it very much depends on the belay device and the karabiner to allow the rope to twist in the plate, most modern plates don´t seem to show this effect at all. If you make a plate to take full advantage of the jamming effect the rope twisting is unbelievable!

my understanding is that they tested found the phenomenon on the standard BD ATC as well as the XP in both braking modes ... and they used the old version of the belay master

i cant speak towards the biners ... but the ATC is one of the most common device in north america and hasnt changed much since the article was published in 2007 ....

the XP has been "updated" with holes in the sides to reduce weight, but the basic design is still the same in the modern version ... it would be interesting to see if the phenomenon still exist with the current rocklock/belaymaster/attache round stock biners ...

many of us are still using the old versions of the XP or its derivative, the guide ...

it would be very interesting indeed to find out if the increase braking effect exists on the most common devices still with the common belay biners ... and if so, to what degree does the suppleness or stiffness of the rope affect it ...

interestingly enough as well their test show an increase in braking power of the munter as the rope diameter got smaller ...

hmmmmmm

;)

Jonathan Dull wrote: You actually made several assumptions about everything I said and inserted words that I never typed.

I got the exact opposite impression.

wfscot wrote: Here's some really interesting empirical data regarding dynamic belay and the force on the top piece: rockandice.com/lates-news/w… On the scary side, note that a .16FF fall with a light (145lb) climber can generate up to 1300lbs (almost 6kN) of force on the top piece. That's past the rated strength of a lot of small gear.

Ah, the dynamic belay jump theory. Sure , when executed well , it will reduce fall forces. But even the two experts from Rock and Ice intentionally trying to execute this took three tries to get it right. In the real world you don't get three tries.

Sure, it can be done, but it requires practice, planning, belayer paying very close attention, and near perfect timing. I believe rgold had some test results showing the jump was always after the peak load an was ineffective.

Just get a light weight belayer. Works every time.

bearbreeder wrote: my understanding is that they tested found the phenomenon on the standard BD ATC as well as the XP in both braking modes ... and they used the old version of the belay master i cant speak towards the biners ... but the ATC is one of the most common device in north america and hasnt changed much since the article was published in 2007 .... the XP has been "updated" with holes in the sides to reduce weight, but the basic design is still the same in the modern version ... it would be interesting to see if the phenomenon still exist with the current rocklock/belaymaster/attache round stock biners ... many of us are still using the old versions of the XP or its derivative, the guide ... it would be very interesting indeed to find out if the increase braking effect exists on the most common devices still with the common belay biners ... and if so, to what degree does the suppleness or stiffness of the rope affect it ... interestingly enough as well their test show an increase in braking power of the munter as the rope diameter got smaller ... hmmmmmm ;)

Might of course just be something to do with the make of rope they used, their 8.9 might be a harder weave than the biggerer ropes which makes a lot of difference. We tested every mm size of rope/cord from 4 to 12 and the increase in power with diameter is a fairly good curve. But testing rope friction is never too exact, 10% variation is nothing and we did mostly 5 pulls and averaged the curve to get the trend.

climbing while dicking in small marginal gear and uttering profane and prophetic doomsday outcomes is one of the greatest joys of climbing. if your belayer's hands aren't sweating, you aren't really living....

Considering I know you Slim… That's the funniest shit I have heard in awhile!

another great joy in life is climbing so slowly, that your partner is about to wet his pants at the hanging belay, and finally says - dude, either do it or pull on gear, i gotta piss! :)

this is trad IMO

Phil Esra wrote: Got it, thanks for putting it in words I can understand! Pumpy, with a pretty clean fall. Takes small nuts well. I would definitely leave the 00 behind, but to each his/her own.

Er, oops, just got on C&B again. A couple of purple Master cams would've been quite handy, actually, and I would have gladly spent the time to place them. Just this once.