Back to the Drawing Board

October 17, 2013

The trunk of my car is starting to look like a bag designer’s.  In this pic, I count six different bags by five different companies.

We have our first mockup from Chip and are making some changes.  Our primary goal is to finalize the dimensions so we can move on to “features.”  Some things we learned:

1) It’s too big.  Our original design came in at 60+ liters for both panniers.  It looks huge next to a bike, almost like a hard bag.  So we’re trimming the size and adjusting our patterns, bringing the volume closer to 46 liters for both bags, 52 liters with pockets.  Capacity can be increased using the roll-top, or decreased using compression straps.

2) Even with a smaller size, stiffeners and foam are needed to support the weight of the bag and its contents.  For the next round we’re including an outer layer of abrasion fabric (34oz pvc) , a polyethylene protective panel/stiffener, foam for cushioning, and an inner liner to hold all these parts together.  Plus we have our inner waterproof liner, so it’s a bit like making 5 bags at once.

3) Our exterior pocket is too small.  We want to fit two 1 Liter MSR-style fuel bottles.  That way the rider can carry an extra gallon of gas over two panniers.  With our original design, two bottles would fit but one would rub the zipper, which could cause the zipper to fail over time.  We’re also planning a second external fuel storage solution, so the rider can choose between using the main pocket for fuel or using it for tools & tubes.

4) Our roll top doesn’t work the way we hoped.  Our first design featured a “teardrop” for the roll, which is something we see on a lot of nicer drybags.  A teardrop reduces the extra material to be “rolled” in closing the bag.  However this makes the bag’s throat so small that we can’t remove a fully stuffed liner.  Plus it looks crappy.  So we’re going back to a straight-throated bag for the next round.

Teardrop Throat

Straight-Throat

This is what my kitchen looks like after an afternoon of pattern revisions.  I barely even knew what a “pattern” was a few months ago.

With the newly revised patterns, a bunch of changes, new fabric that’s closer to our final spec, and some added accessories like compression straps & buckles, we headed back to Chip’s for another round of cut & sew.

And then… because the weather’s sunny and the dirt’s perfect…  we left the “office” early to enjoy it!

Next up: reviewing the revised prototype, adding exterior features, more focus on the mounting system, and starting on the duffle shape.