To Arc or Not to Arc

Hello All,

I'm the recent owner of a Arc Haul backpack. So far I really love it.

Question on the arc: To any owners of an arc type series Zpacks pack, do you "unarc" the pack every time you empty it (at camp, home, etc.) and then arc it again when you load it? Or do you leave it "arced" all of the time?

Thanks.

I use my pack as the base for my pillow, so I empty it and release the tension straps every evening. I release them before storing at home as well.


Sent from my iPhone using Tapatalk

I leave mine arced pretty much the entire trip, unarc at home

The "arcing" straps on my Arc Haul kept slipping when I first got it, so I sent it back to Zpacks to fix. Now they are difficult in the extreme to release - good. No more slipping. Consequently, I never release the arc until I'm finished with my hike (usually a LASH). Doesn't seem to harm the rods over the last couple of years of use.

I leave mine Arc'd all the time EXCEPT when travelling with it. I don't think this does any harm. I release the arc, and hence the tension in the back mesh when I check the pack as baggage on airlines.

Many years ago my son had a bow flex exercise machine. It had carbon steel resistance rods. He stored it in the arch position. It lost its flexibly over the years and became not very useful. I think this is the same material that z packs uses and so it seems that at least for longer storage, the carbon steel rods should be released from tension to avoid fatigue of material and premature loss of function. I am not a structural engineer, just have noticed this in my own life.

My take away is : longer storage release tension, extended hikes, probably should release tension nightly. Not such a big deal to retighten every day. That said, it’s your pack! Do as you choose, enjoy your trip!

I un-arc it at home.

I just got my Arc Blast repaired after one of the tensioning straps ripped off the pack while setting the Arc. It's always been a bit of a PITA to set, so I just release when I get home.

Thanks for the advice so far. I just got back from a two day backpacking trip. I am loving my new Arc Haul and Duplex tent. They have saved me a bunch of weight. I did not "unarc" it any at all on my trip. I am headed out next week on a three day trip. I think I will just leave it "arced" until afte then and then "unarc" it when I get home then. I think I have decided to "unarc" it while it is at home.

Mine normally stay arc’ed during the trip, and I release it before I load the pack into my truck.

I must admit I never release the tension - ever. Once I get it set where it is most comfortable I want it to stay there and not move. IF I have to take the pack apart, or for some reason the tension slips from where I like it, I seem to take forever to get it just right again - I guess I am picky. So once it is 'there' I leave it there.

btw I have found with my Arc Blast that is it far more comfortable for load carrying (I often have to do big water carries out here in the desert) at or above pack wt rating when you have almost zero arc to the frame. The pack just carries more comfy - it also much easier to pack without a big bend in it. Yes it is not quite as cool this way as the wind will not go between the pack and your back so well - but I have always thought this 'feature' was essentially a marketing spec and not a performance spec as I don't think it makes any real difference. ymmv