On my recent mission to conquer the Vapor Trail race course, brought along plenty of off-the-shelf gear.  I also made a few things to really suit the trip I was taking and how I planned to carry things.  I wanted to stow my down gear – a Montbell #1 Super Spiral Down Hugger sleeping bag and my trusty GoLite Bitterroot puffy – in a dry bag, strapped to my handlebars.  I bought a McClure handlebar harness from Defiant Pack to hold things on the bars, but I needed to enclose the down gear.  There were a few options out there, but none really suited me.  I still had some cuben fiber (non-woven dyneema composite fabric) sitting around from a previous project, so I set off to make my own.

myog cuben dry bag bikepacking how to

Dry Bags for Bikepacking

I didn’t have to make my own dry bag.  There are plenty of options out there that would do the job.  Sea to Summit’s Ultra-sil Nano sacks and Outdoor Research’s Ultralight Dry sacks are good, relatively inexpensive silnylon options.  A 15L sack should do the trick.  You can also get pre-made cuben sacks from Zpacks, Hyperlite Mountain Gear, and others, though none are quite the proper dimensions.  (Also note, HMG’s sacks are sewn and not taped, so they aren’t officially waterproof.)  For bikepacking-specific use, you may want a dual-ended bag like the Revelate Saltyroll that lets you access both ends of the bag without emptying it.

myog cuben dry bag bikepacking how to

And why would you want a dry bag in the first place?  For the most part, you’ll find that companies make harness systems for your handlebars.  To stow gear on the harness, you need a dry bag.  There are a few that make integrated bag/harness systems that strap directly to your bars – Revelate and Ortlieb make two – but then you, in my opinion, lose some of the versatility.  You’re stuck with that bag, even if you have a small load.  I like the idea of having a separate harness and bag.

Also, the Ortlieb and Revelate, while both bomber and totally waterproof, have to be unstrapped from the bike if you want to bring the bag into your tent.  A dry bag/harness combo means you can leave the harness on your bike and take the bag with you in the evening.

Make Your Own Cuben Bikepacking Dry Bag

After measuring my cockpit, I figured I wanted a dry bag that was about 8″ in diameter and about 20″ long when fully stuffed.  Through some unfortunate trial and error, I determined that an 8″-diameter stuff sack loses about 3″ of length from flat dimensions when full.  It also loses 2″ of length for each roll and 1/2″ of diameter to the seam overlap.  So if I wanted a 20″-long, 8″-diameter bag, I needed to cut a 27″x26″ piece of cuben.

myog cuben dry bag bikepacking how to

Cuben fiber is tough stuff.  Our kitchen shears weren’t sharp enough to cut it.  I ended up finding one of my many knives that did the trick.  A fresh blade in a utility knife, exacto blade, or rotary cutter would probably work, too.  After cutting the sheet to size, I ran a length of 3M double sided tape along one of the 27″ edges, peeled the backing off, and carefully pressed the opposing edge onto it to form a cuben tube.

The prior, unfortunate, experiment also provided knowledge that cuben dry bag rolls don’t stay rolled unless you stiffen them somehow.  So, next, each end of the tube received an application of 1/2″ adhesive velcro – hooks on one side and loops opposing – to both hold the openings closed while rolling and to stiffen the rolls themselves.  With the velcro in place, I attached 3/8″ buckles using scrap cuben and more tape.

myog cuben dry bag bikepacking how to

I suggest letting the tape set up for a while before placing it under any tension.  If you pull on it to soon, it may shear a little bit.  Once everything is set, you’ll have a nice dry bag, suited perfectly for your use.

Home Made vs. Store Bought Dry Bag

The Revelate Saltyroll is 7″ in diameter and 24″ long when rolled; overall volume is about 15L.  My bag is 8″ by 20″, with an overall volume of 16.5L.  The Saltyroll weighs 6.2 ounces.  My bag weighs 26g or .9 ounces.  An extra 1.5L and 1/7 the weight = chicken dinner!  (Salsa Cycles makes one too.  It’s even heavier.)

myog cuben dry bag bikepacking how to

I think the first time I made a cuben bag, it took me about an hour.  This one went faster because I knew what I was getting into.  Less than an hour of time to save almost half a pound ain’t bad, in my book.

Materials list:

  • .74 cuben fiber from Zpacks (fifth item down)
  • 3M tape from Zpacks (second item down) (I think this is the same stuff from Amazon for much cheaper. But I haven’t ordered it, so please don’t be mad if I’m wrong.)
  • 1/2″ adhesive velcro from Amazon
  • 3/8″ buckles from Amazon (the buckles I used are only available in 100-packs now.  Maybe try these.)
  • Cutting surface – I used a broken-down cardboard box
  • Cutting tool – sharp knife, utility knife, exacto blade, rotary cutter
  • Measuring tool – I used a carpenter’s square, which I like because it holds the material down.  Anything with measuring marks works.
  • Marker – Sharpies are awesome.

If you have any questions about making your own cuben dry bag, head over to our Facebook page and leave a comment.