In reply to Jamie Bankhead:
Why would mixed ground be any different to a trad fall? I use these ropes for summer climbing too. But yeah I don't fall off much on any form of trad! Although one of my climbing partners seems to like testing them
In any case when I have gear on both ropes that would prevent a nasty fall, I consider this enough redundancy for me. I'd certainly be feeling a bit shaky about taking a fall where only one 8mm was protecting me from likely injury especially if there were any sharp edges about or the fall may involve a swing and the rope sawing across an edge, but then I'd really want a 9mm to be starting to feel more bomber in these situations anyways.
I agree though the thinner the rope the more likely cut, abrasion resistance as mentioned hasn't been an issue though, and threads regularly come up confirming this point with phoenixes.
As with many climbing related decisions I don't think there is a right or wrong answer and it's down to informed personal choice. The main factors I'd consider when buying half ropes are:
- sharp edge resistance / likely hood of getting cut.
- retention of elasticity over multiple falls (how often will you fall on these). Indeed if you fall a lot 8mm may not be the best idea due to rope wear either!
- safety of bringing up a second on a single line (how often will you climb as a 3 especially where the seconds are likely to actually fall off).
- Weight for both walking in and whilst climbing.
- Reduction of drag using thinner ropes.
- Increased tangle factor of thinner ropes.
- Max force on gear.
- Abrasion resistance (although as mentioned 8mm's don't necessarily under perform in this regard).
- Will I be using the ropes in a wet environment? do I require dry treatment.