The ropes at our gym have been flattened from excessive lowering with Grigri's and having taken a couple of small leader falls on my fairly new rope myself, I set out online to figure out how much life my rope and the gym’s rope have left. I found some good info but also wanted to throw this out to you all to get your input.
addresses the flattened rope issue. A lot of speculation and skeptical responses, but the last couple clarify the issue. It sounds like it’s not a problem for top roping (TRing), though I’d be less enthusiastic about using that rope for a challenging lead with runout.
The consensus about general rope retirement on this thread
seems to be “ignore the falls and just check the rope for irregularities…unless it’s a high fall factor”
An interesting point brought up in the above thread includes a link to an article (with high geek factor) about using the same rope for TR and lead climbs. I highly recommend struggling through this if you use a Grigri and/or lower on your ‘lead rope’. (Their concern with TRing is not the falls, but with the lowering which most of us do after every climb; lead or TR)
ACC link: Rope elongation and TRing
In summary, the lowering action strongly reduces the elasticity of your rope, thereby reducing the number of rated falls by ½ (after 80 lowerings)
Two concerns with the affects of Grigri’s on rope integrity:
1) It is a static belay device. Meaning that it has zero capacity to absorb the shock of a fall (when it catches, it locks (although the bounce/uplift of the belayer does absorb some shock)). ATC’s or other similar function devices have a small amount of slippage before fully catching the fall which absorbs the shock better (those who use these devices can attest that the slippage may not even be noticeable).
2) When lowering a climber, (after TR or lead) Grigri’s add an additional dynamic shock (that other devices don’t) on the rope. The article states that since the lowering speed cannot be finely adjusted the speed “must be sharply slowed down” just before the climber reaches the ground (hence the additional shock). [Personally, I think this could be avoided by a smooth skilled belayer]
How do you determine how much life your rope has left???
(edit: fixed links)