Tag line vs. twin/half rope for big wall zip line and alpine climbing

I’d like to invest in a tag line or twin/half rope to use as a zip line for big walling as well as when I need a tag for rapping in the alpine or multipitches. I like the idea of a twin/half in case something happens and you need to re-lead but of course tag is lighter. I realize that the use case for big walling and the alpine are different but would prefer to just buy one rope to fit both needs. I’d appreciate your recommendations! 

Sterling 7mm tag line is pretty good.
https://sterlingrope.com/7-mm-tag-line/

Tag. I hardly use my twin ropes. I end up fix and following while hauling a pack in the alpine more than I would benefit from having twins. Rope management tends to be better with a tag, plus I don't feel so bad using the rock as pro or a belay when it's full-sized. 

Go with the Edelrid rap line if you want the best of both worlds. You can lead on it in emergencies. 

I did a wall once with a 7mm static line as the zipline. Never again! It just didn't feel strong enough. I watched that skinny cord rubbing over edges and roofs and I was like, "Boy, that was a dumb idea..."

Better a skinny unicore rope like Beal, which you can jug on safely or even lead with in a pinch. 7.9mm was too skinny, 8.2mm is perfect.  Very little weight difference between 7mm and 8.2mm. 

Any of the 6mm semi-static tag lines are what you want. I’ve been using the petzl pur line and have been fairly happy with it.  Also used the maxim/espirit versions in the past too and they’re great. 

If you want the lightest “tag” line (not to be confused with “rap” line), then the PUR is one of, if not the lightest option. However it is essentially *pull-cord only*, I do NOT enjoy rapping on it, when mated to the lead line. The Esprit/Maxim APER is a little bit heavier (maybe .75lb) than the pur line, but raps like a dream, especially when you put two biners into your atc and thread both lines. APER is way less expensive, but can be tough to find. Also doesn’t fold up/wad up like the PUR does, you basically cram the pur line into a jetboil sack.

Christian Hesch wrote:

If you want the lightest “tag” line (not to be confused with “rap” line), then the PUR is one of, if not the lightest option. However it is essentially *pull-cord only*, you do NOT want to rap on it, mated to your lead line.

I've rapped on the PUR line paired with a single rope quite a bit.  Other than it being counter to Petzl's stated recommendation as a retrieval-only cord, have you had problems rappelling on it?

Max Tepfer wrote:

I've rapped on the PUR line paired with a single rope quite a bit.  Other than it being counter to Petzl's stated recommendation as a retrieval-only cord, have you had problems rappelling on it?

I have too and it's been fine aside from one time it got wet.  A little extra attention needed but no biggie

Max Tepfer wrote:

I've rapped on the PUR line paired with a single rope quite a bit.  Other than it being counter to Petzl's stated recommendation as a retrieval-only cord, have you had problems rappelling on it?

As long as the lead line is threaded, it’s extremely slippery but manageable for a two rope rap. On the next rap, when you’ve pulled and now have the PUR threaded, the PUR runs so damn fast, even with two biners in ATC, that it requires a LOT of force on the pur line (you almost don’t need to grip the lead line!) to maintain a comfortable rate of descent (and to keep the knot from sliding way down from the rap anchor). This is a sample size of only 4 raps, on a brand new pur, but I was not a fan at all, especially compared to the APER. I would guesstimate that the force required to equal the rate of descent on an APER is at least 8-10x on the PUR.

Don’t get me wrong, it’s nearly a whole pound lighter than the APER in a 70m, and it squashes into any crevice in your pack (the APER has to go in first, in a U, then pack everything in the middle of that), so it certainly has some benefits but I was very turned off the first time I used it. Maybe I should try again but I had double biner in ATC *and* a rap glove, and it was a LOT of work to maintain solid control over - fwiw, I do *not* run a 3rd hand on familiar rappels, so perhaps that would help. I have used the PUR to haul a 15lb Creek20, and it performed very well in that function.

Edited above post to reflect “personal preference”  :)

Christian Hesch wrote:

As long as the lead line is threaded, it’s extremely slippery but manageable for a two rope rap. On the next rap, when you’ve pulled and now have the PUR threaded, the PUR runs so damn fast, even with two biners in ATC, that it requires a LOT of force on the pur line (you almost don’t need to grip the lead line!) to maintain a comfortable rate of descent (and to keep the knot from sliding way down from the rap anchor). This is a sample size of only 4 raps, on a brand new pur, but I was not a fan at all, especially compared to the APER. I would guesstimate that the force required to equal the rate of descent on an APER is at least 8-10x on the PUR.

Don’t get me wrong, it’s nearly a whole pound lighter than the APER in a 70m, and it squashes into any crevice in your pack (the APER has to go in first, in a U, then pack everything in the middle of that), so it certainly has some benefits but I was very turned off the first time I used it. Maybe I should try again but I had double biner in ATC *and* a rap glove, and it was a LOT of work to maintain solid control over - fwiw, I do *not* run a 3rd hand on familiar rappels, so perhaps that would help. I have used the PUR to haul a 15lb Creek20, and it performed very well in that function.

Edited above post to reflect “personal preference”  :)

This has been my experience as well. An easy fix is to thread the PUR line so you don't lose it, but then tie a BHK with the dynamic rope and PUR line and clip it to the anchor. One person raps on the dynamic rope as the other unties the flat overhand, removes the PUR line from the rings, and replaces it with the dynamic rope. Retie the joining knot, add a carabiner block if desired, untie the BHK, and go. 

Now you get to rap on the dynamic rope without risk of losing the ropes while you pull. 

Kelsey, a lot of discussion here on the ultralight skinny special purpose ropes. Those posters are experienced climbers, based on my reading their posts for over a year. I however more am in Peter's camp on this issue, for general purposes, or day in day out climbing. Your own thoughts supporting a twin or half rope in my opinion are equally valid,  particularly the half rope. I would even potentialy go further, like a twin/half/single, or a pair of half ropes or pair of triple rated ropes. "Double ropes" can offer other flexibility/options, that I have made good use of in the past, on everything thing from classic alpine climbs to guiding big walls in Yosemite. There are both pros and cons to any of the now three options referred to in this thread. It is good to be aware of all of them. And pick what makes the most sense to you for most of your climbing.