Chair enlightening – 13 oz full chair

[Alan W]

Brian, suggest review https://backpackinglight.com/forums/topic/chair-feet/#comments

started by Tim Garner for additional ideas at feet.

[JCH]

IME, the crossed “Garner straps” are the best solution yet devised…a minimalist version of the Helinox ground sheet.  No individual foot design is likely to achieve the same purchase on the ground surface.  @Alan W’s use of the Spider 1.5 webbing yields a sub-11g system weight.

[Brian T]

JCH, Alan,
How thick/ tough is the spider webbing? like could you eliminate the rubber feet and it would protect the carbon enough from hard surfaces?

 

[JCH]

Brian T – while extremely strong, Spider 1.5 is also quite thin.  I would expect the sharp edges of the carbon tube end to damage the webbing quickly.  It might be possible to round/smooth the raw carbon tube end sufficiently to avoid damaging the webbing. If a smooth round plug were inserted I think the webbing would work well.

The cut down feet you posted would definitely work to prevent damaging the strap material.  Perhaps they can be further reduced?

FYI, I used the 1” spider webbing for my hammock chair suspension. I believe Alan W also used the 1” for his cross straps. The 2” would IMO be overkill, and might actually be too wide to work well.  Alan W’s pictures in the previously referenced thread show the straps beautifully.

[Brian T]

JCH,
Thanks for that, there are round plugs in all tubes they hold the shock cord inside of them so they are not sharp in any fashion, however, carbon is kindof sensitive to serious abrasion, for example you can sand it with sand paper. The rubber feet do help spread some of the pressure on the carbon to make the contact point more durable (this is one reason carbon trekking poles typically have the whole point made from metal, not just the very tip).
I can post pictures if my explanation doesn’t make sense.

[JCH]

Makes perfect sense. I would suggest continuing to use the rubber feet to broaden the contact point. The trick will likely be identifying the point at which the foot still works, but will no longer do so if made any smaller :)

Wondering if a minimal foot could be crafted from another, less dense material…cork?  After all, it is no longer a “foot”, but a buffer protecting both leg and strap.

[Brian T]

JCH,
Thanks for this idea I was thinking something similar but wasn’t sure what material might be durable and light enough. I ordered some cork tapered stoppers to try that, it’s a really interesting idea.

[JCH]

Ace Hardware has a lot of stoppers in various sizes and some alternative materials.  Might be worth a visit.

[Brian T]

hey folks,
sorry for a period with no posts. I have done several experiments since the last post. the R&D of it all takes some time.
My first run is complete, I made some sets of poles, and got a few to some beta testers to see what their experience is like.

I’v had to make some changes to the design as I have used the original prototype some more, mostly working with clearances and small material changes.

I am currently still in the process of working on the chair fabric (I’ve enlisted a partner who is better at soft goods work that myself).

I’ll keep you all posted as the other parts develop. Thanks for all the ideas so far.

[Tjaard Breeuwer]

@Brian T,

I have been thinking of this same idea: swapping the aluminum poles of our Helinox Zero’s  for carbon ones. Thanks for going ahead and doing it! We have 4 in our family, so it would be worth the effort, since I could do 4 of them at once.

Do you have a suggestion for which tubing is most appropriate for this use (balancing cost vs pole stiffness vs crush resistance)?

Thanks!

and I’m also interested in an UL Chair if you made one.

[Brian T]

Tjaard, sorry for missing this I was on an extended trip to the coast.
I DM’d you something similar, but if you have already bought the Helinox chairs I don’t recommend doing the pole replacement on them. The poles are significantly smaller OD and it doesn’t make for a good candidate for the swap.

[Brian T]

OK pretty big update here. I have been quietly working on this project in the background but had several things come up. However I’ve made progress on several aspects of this project:

Here is my most insane creation(307.9g/10.8 oz for a chair with a stuff sack):

1. This is my original prototype, in this case I did the following upgrades/ weight cuts:
   poles swapped for carbon (saves about 102g/ 3.6 oz)
2. Swap the seat fabric for a custom one made from .7 monolite/.67dyneema/dyneema webbing (saves 55g/2oz)
3. swap the stuff sack for one made from 0.7 monolite with Dyneema 1mm cord (saves 25g/.8 oz)
4. Swap the shock cord for thinner shock cord (saves 11g/ .4oz)
5. swap the ruber feet for eva foam balls (saves 8g /.3 oz)

For comparison the REI chair straight from the store is 484g/17oz

This means these modifications have saved just over 6 oz.

Here is the ultimate weight weeny set up ready for a sit:

Here is a more moderate version I also worked up:

This version is 341 grams, but has some considerable “quality of life” differences:

1. It retains the original shock cord (not structurally important but more spring and a little better user experience than the super thin stuff I used on the first prototype)
2. It has a more durable seat fabric design, but still a lot lighter than the REI fabric (this one is made from 1.0 Monolite, nylon bias, and dyneema webbing reinforcement. I think this is a much more durable (albeit slightly heavier) design/material selection.
3. It also has other minor differences, for example this is a .67 dyneema stuff sack, which is a 1g penalty over the monolite (because it is taped not sewn, the Dyneema is actually lighter per yd, and it is a different generation so the hubs are slightly different (my original was an older design)
4. It retains the shock cord through the center pole (making this pole replaceable)

IMO, the penalty of 41g is likely worth it in this case. It is still 143g/5oz lighter than the original with no real penalty to usability. If you wanted to carry it around with no stuff sack you certainly could and save another 8g.

BTW I had help with the sewing from my friend Ian (he makes some amazing UL gear and does custom work too)

[Bill Budney]

This is great. Do you use the hubs from the original chair, or is all of it your own stuff now?

[Brian T]

@bill the hubs are from the original chair, the cord locks are also from the original chair. If I had a way to make the hubs and the cord locks (the attachments for each of the ends of the shock cord) then everything would be made by me.

[Brian T]

There is a guy I found on Etsy who 3d prints the cord locks. I doubt 3d printing would be strong enough for the hubs though.

[Brian T]

For those who might be interested, I was inspired by this thread, and the so far good reports from some beta testers. I made a run of 10 kits to start and posted them on etsy. DM me if you are interested in trying one out.
Thanks to everyone for all the excitement and good ideas.

If anyone has other gear they wish someone would engineer some modifications to make it lighter I loved this project and am looking for other ideas.

[jscott]

12 ounces! pretty darn good! It would appear that skeeters could bite through the mesh seat though…I’m not sure if my trusty REI nylon pants would block their proboscises…but never mind!

after trying different less good iterations of a camp chair, I’m still back to a 5 ounce hammock chair. I brings my legs and feet up off the ground and gives back support. True, in some situations it wouldn’t work–no trees! But it’s super light and packable.

With camp chairs, I could never find comfort with my butt near the ground and being unable to comfortably extend my legs and feet. Usually, finding a rock or log where I could place my butt higher up off the ground was more comfortable than a camp chair. Not everyone’s experience is the same! again, kudos for all the innovation going on here.

[Brian T]

@bill recommended I post my etsy links here for those who want to look at them.
Just the pole kit:

https://www.etsy.com/listing/1785436574/rei-flexlite-carbon-replacement-poles

The complete chair (the pole kit installed on a brand new REI Flexlite Air):
https://www.etsy.com/listing/1799642001/worlds-lightest-camp-chair-modified-rei

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