Heavyweight Ultralight Backpack

Very nice indeed.

GG specs the aluminum stay at 6" wide. Is that what you got? I looks wider.

Also, approximate volume?

Looks fantastic. I love seeing something so purpose built.

I consider 210D gridstop a thoroughly midweight fabric.

Nice work Andy. It's pretty cool you managed to get an aluminum frame into a pack and keep the whole thing under a pound.

How have your other cuben packs held up long-term? Every cuben product I've ever had that didn't have taped seams ended up with the seams pulling apart after a year or two. Basically the mylar tore at the stitches and there's just the spectra threads holding it together. It makes me skeptical of any stitched seams in cuben.

Oh, and great TR from Ionian! Makes me want to go back to the NF Kings River sometime.

Thanks for your comments!

Greg, the stay is 6" at the top and flexes to 10" at the bottom. With the 25" length it could probably stretch to 12" at the bottom.

The total volume is about 3,000 ci. 2,300 for the main pack, 300 ci for the side pockets and between 200 – 400 ci for the rear pockets.

David, I didn't realize the 210d was a midweight fabric until after sliding down a granite wall while wearing it. The were a few cuts and holes in the bottom.

Andrew, I've had the same experience with sewn seams on stuff sacks made with the lighter 0.50 cuben. After two years they start to disintegrate. The backpacks have held up much better, although I usually end up making a new one each year to try a new design. For this pack the seams are sewn and taped. Reinforcing the pivotal attachment areas with 3 layers at 45 degree angles also helps.

I'm going to try a modular design next with the ability to easily use various combinations of shoulder straps and hip belts on the same pack body. UL, SUL or daypack all in one.

Maybe a snowshoe trip into the Ionian Basin would round out your monthly Sierra goal this winter? These guys did the (other) Sierra High Route on snowshoes:

http://photos.offyonder.com/Snow/Trans-Sierra-Snowshoe-Trek/

That's a nice looking pack! Good weight with a frame too!

Andy, that's an awesome idea. I wonder if we could piece together a route to Ionian that avoided avalanche danger? They close the road to Wishon at the Dinkey Creek bridge, but I bet you could jump the gate and ride mountain bikes from there to the trailhead. I haven't had any avy training, maybe a trip like that would be a good excuse to go to a class. I've got a spare ice axe and crampons…

Thanks Dave!

Andrew, I've have been considering going in from the east side. Possibly over Lamarck then Wanda Pass on the way in, and Black Giant Pass to Echo Col on the way out (or some variation). It's a popular x/c ski route. I have been over the crest via Lamarck and Echo, but only Lamarck in the winter. I would also need some avalanche training. . . it sounds like a lot of fun!

did you look at using masons line+line locs instead of nylon straps?
did you experiment at all with taping the cuben instead of sewing?
did you make any observations of hip belt vs frame in support of weight?

thanks!

Thanks Steve. In the past I've tried using lightweight cord with a taut line hitch for shoulder strap adjustment instead of the nylon straps. Although the cord worked ok with the taut line hitch and it may have saved some weight it just didn't seem to work very well. I haven't tried the cord & cord lock for adjustment. It looks like Gossamer Gear has used that technique in some of their more recent designs so maybe I'll give it a try next time. It must be good if it's good enough for Glen Van Peski.

Taped or bonded seams have worked really well for dry bags and w/b rain mitts. I wouldn't want to trust the seams on a backpack with just taping or bonding. On the most recent packs I've made the seams are sewn and taped. For the main seam I borrowed the triple stitched flat felled seam from Joe @ Zpacks which is amazingly resilient.

I'm not sure what you mean regarding the hip belt vs. frame for support in weight so my answer may be off target. The 6" wide hip belt combined with a lightweight frame really holds weight comfortably when carrying a bear canister and enough food to hit the 25-28 lb range . The weight transfer is good enough that a small shaped shoulder strap works really well.

For the smaller packs that are made to be used for under 15 lbs I've been using much smaller hip belts, usually around 2" – 2.5" wide and that feels like plenty. Even when carrying a smaller canister like the Bear Boxer Contender (horizontally) the smaller frameless pack works fine as long as the total weight is under 15+- lbs.

I'm not sure that helps, but let me know. I'm always interested in trying new design ideas.