Dirtbagging your bags: making your own seatbag

I had seen folks make their own soft bags from scratch, basically mimicking the commercial/custom bags.  Some of them were very well done and cost very little to make.  A frame bag was not something that I wanted to try and make, especially since I had limited access to a sewing machine.  But a seat bag seemed easier.  It had occurred to me that, if I could begin with something like a stuff sack of sorts, then perhaps with a minimum amount of straps and buckles, and a bit of borrowed time on the sewing machine, that I could make one.  How hard could it be?

Well, it was harder than I thought.  One thing that happened in the process was that I came to appreciate the work and design that went into the CDW seat bag I was using for inspiration.  All the different fabrics, gussets, rubber and velcro pieces...it all comes together to work very well and until I tried to obtain the same level of function in my own way, well, I just did not get it.  I do now.  Relevate and Carousel Design Works earn their wages.  In fact, they are underpaid.

So, back to the search for a basic bag to build from.  I chose a compression sack from Jandd products, since I will be looking at another piece of gear they make later on.  I chose a small sized one that was approximately the length and diameter of the seat bag I already had.  The compression straps, four of them, were already there, as well as a drawstring closure on the main sack, and a cap over that that catches the compression straps.

I knew I needed another strap across the saddle rails and one more to keep the back end pulled up.  As well, some kind of velcro section around the seatpost.  To see what I was dealing with, I stuffed it full of my tent and such and put it in place under the saddle.  I had paid a visit to the local camping store and bought three straps and fastex type buckles.  I mocked up the position of the bag with those straps and some clamps and went pedaling.

It immediately hit my legs.  The bag was too wide at the end and it hit me with each pedal stroke.  Looking at the CDW bag I could see how it tapered at the seatpost end.  That required I narrow the stuff sack.  I also found out that it needed structure to keep some shape to it.  Otherwise it would be a lumpy blob.  I had some plastic sheeting from work that was a nice blend of stiffness and flex.  I went through about 4 different versions before I came to the two shapes that I held together with double-sided tape.  It gave me the wedge shape I needed and the internal structure too.  It slid into the compression sack. The top, sides, and bottom all folded in to make a shaped 'box' of sorts, keeping the end of the bag taller than it was wide.

 

From there, I added a section of strap that had two buckles, one that fit over each saddle rail and sewn tight into the bag in the middle of the two buckles.  Another strap was sewn to the belly of the bag and had two more buckles that fit to the saddle rail strap ends.  I added a wider strap that was intended to catch the bag at the back end, just under the bottom edge, and lift it towards the saddle, wrapping around the seatpost in the process.  I also placed the bag so that the built-in compression straps were in a X shape, not a cross.  I thought that would give me a better 'four-corner' compression.  It also placed the Jandd logo right side up. In the pics, straps A are the OE compression straps (4).  Strap B is the one that wraps around the seapost and is sewn just under the rear of the 'butt' of the bag.  Strap C is one of the pair that wrap around the saddle rails and are sewn in pairs both on top of and below the bag.

The seatpost is a natural spot for velcro as an attachment method.  But the sewing machine was pretty lightweight and the seamstress (JeffJ's wife) was having issues dealing with the thickness of it all.  Plus, I was not all that happy with the overall stability of the bag.  It wiggled too much side to side.  I was having a lot of trouble getting the same amount of stablity that the CDW bag had.  His combo of inner stiffeners, rubber sections, and materials with more heft to them was a tough combo to match.  I was thinking about what I could use instead of velcro and I came up with a solution.

Mini rubber clamps.  They are heavy duty rubber, adjustable clamps that come in different sizes and will hold a heavy load.  I picked up a couple of small sized ones and, using the predrilled holes in the base of the clamps, bolted them through the bag and the inner plastic panels.  I used 8/32 screws and nylock nuts for fastness.

I fit it to the Lenz, stuffed it full of down vests, a camp pillow, and a windbreaker, and tightened it all down.  then I cut the strap ends to a decent length and took a good look.  The bag, held in place by the rubber clamps, seems pretty steady.  All that is left is to try it out on a trip and see if it works.  I figure that I have about $40.00 into the bag in materials.  Time?  Well, it took way longer than I thought. The structure part was the hardest and I am still only somewhat pleased with that.

There are some things I might do different next time.  I would consider a dry bag instead of a compression sack.  The material is tougher and some of them come in a rectangle shape so you run them on the long side against the seatpost.  This might keep it away from your legs right from the beginning.  They also have the roll top all in place. 

I do not expect the home made version to be a durable as the custom one.  I think it could be better, but I did achieve a pretty good version of my original vision.  Now whether or not my vision was a good one?  We shall see.  I hope this works after all the time spent.  It is to be used by friends that do not have a bag of their own.  I also hope that it inspires you readers to try one of your own and do it better, then share that with others.  If you can afford a custom set of bags, then by all means, do so.  They are killer.  But if you cannot, and dirtbagging is your only hope, give it a shot.

Comments

[Tony Asef]

Making your own soft bag is doable, though not easy. If you love to sew and create things, then that should not be that hard for you. My mom is so fond of sewing and I see her make stuff like the ones you mentioned.

Tony Asef
http://www.dp-db.com/how-to-repair-sewing-machine