Porteur bag 2

Back in May, I wrote about a custom porteur bag that I sewed for use on my bike. That bag served me well on two trips - a solo ride up to Brewster and back, and my semi-yearly ride on the Empire State Trail, from Poughkeepsie to Brooklyn in two days.

But I had a longer ride in the plans summer, which I just rode two weeks ago: Pittsburgh to DC, 348 miles in 4 days, with two nights of camping. And at the last minute I decided to make the next version of that bag. Specifically, I wanted to correct three shortcomings of v1:

• The attachment system was too complex. It had redundant ways to attach to the rack, but the main method was via a shock cord that looped through six grosgrain loops, plus another shock cord that I attached to keep it attached to the back of the rack. Plus hardware that’s used for attachment is better if it’s less flexible. Bungee cords and shock cords are ultimately pretty flawed as ways to attach things on bikes. My frame bag uses non-stretchy paracord, and most bikepacking setups are reliant on voile straps which have a minimal amount of stretch.
• The bag had no liner, and the material is plasticky and odd-looking. ECOPAK EPLX has a waterproof coating on the outside that makes it look like a plastic bag instead of something from synthetic fabric.
• The bag had way too many panels: each side was a panel, plus the bottom, plus the flap. These made the shape of the bag messy.

Version 2

It turned out pretty well. Here’s the gist:

Materials

• Fabric
  • Base: 1000 Denier Coated CORDURA Fabric
  • Top: ECOPAK 200D Recycled Polyester Fabric
  • Lining: 210D ROBIC Ripstop Nylon
• Hardware
  • Zipper: YYK Uretek Coil Zipper #3
  • Webbing: MIL-SPEC Nylon Webbing 1”
  • Buckles: Dual-adjust Side-Release Buckle (2)
  • Connecting clips: Luorng (2)

As you can see, there’s only one built-in way to secure this bag to the bike: a webbing strap that attaches to the two buckles and tightens below the rack. This is definitely a superior mechanism to v1: instead of attaching just the front of the bag to the rack and having to deal with the back of the bag separately, this pulls and tensions the whole bag, including its contents, to the rack. It rattles a lot less and is a lot simpler to attach.

Construction

This bag is made like a tote bag. The essential ingredient of a tote bag is a piece of fabric cut like this:

The lining is simply: the same shape, again, sewed in the same way, sewn to the inside of the bag but with the seams facing in the opposite direction, so that the seams of the liner and the outer shell of the bag face each other.

Techniques for building tote bags are everywhere on the internet, so it’s a really nice place to start. Plus, the bag body can be made with just one cut of fabric. In this case the bottom of the bag is Cordura and the top is ECOPAK, so I just tweaked the tote bag construction by adding panels of ECOPAK on the left and right of the first step above.

The risky part of this bag was its height and the zipper: ideally it could both zip and the top of the bag could fold over for water resistance. I didn’t accomplish both goals and learned something pretty important: if you’re building a waterproof bag with a zipper, once it’s zipped it’ll be hard to compress because the zipper keeps in air.

But the end of the tour included a surprise thunderstorm in Washington, DC and the zipper kept the wet out, so I count that as a win! The zipper also makes the bag very functional off the bike - using the same strap as I use to attach it to the bike but using that as a shoulder strap makes it pretty convenient to carry around. This really came in handy when we were moving bikes onto and off of Amtrak trains.

Plans for version three

Mostly kidding - I’m going to actually use use this bag for the next few trips instead of tinkering with it. But I do have thoughts, from this experience:

• I have mixed feelings about using Cordura next time. It’s what everyone does, and it helps with the abrasion that the bag experiences from the rack. But I have a feeling that ECOPAK would hold up for many thousands of miles by itself, and is lighter and more waterproof than cordura. It could be cool to make the whole bag body from the same material.
• I think I’ll make the next bag taller, and skip the zipper. I have more faith in folding over the material rather than relying on a waterproof zipper.
• A good system for tightening the straps still eludes me. This setup included sliplock slide adjusters, but it’s still kind of annoying to get the right angles to pull the bag tight.
• Again, I didn’t add any external pockets. I don’t think they’re absolutely necessary, but as it is, like the previous version, it’s not really possible to access the contents of this bag on the move. Which is fine because I have other bags that are easier to access - on this trip this bag carried my clothes, camp kit, and backup spare tires, so nothing essential in the middle of the day.