Transverse (Carradice-style) saddlebag

[Krampus Snail]

Hi folks. I want to make a sideways seat bag, like a Carradice or like this bag:

http://www.pedalingnowhere.com/gear/diy-longflap-saddlebag-minimalist-bike-touring/#.VCGeHGSwLXY

It will be sitting on a Nitto R10 rack. I like the look of cotton canvas, but I'm going to go for a synthetic instead, and webbing with buckles for the straps. I'm going for a double daisy chain and then webbing straps with quick-release buckles on the bottom to attach to the rack, but I'm not yet sure on how to attach to the saddle rails.

Any suggestions for what fabric to use (Cordura?), how to attach to the saddle so it's easy on easy off, and how and where to stiffen the bag?

I did a little four day trip last week, using a Carradice Nelson Longflap plus a handlebar roll and frame bag, and discovered that the seat bag was sort of handy when I was doing hike-a-bike. I could put one hand on the bars, one hand on the saddle, and rest the saddlebag on my hip so I could push more easily with my legs. I'm thinking of putting some kind of pad on the left side of the bag. But not for the first prototype.

For those who would ask why I'm not using a more standard seatbag like Revelate and Porcelain Rocket make, I wish I could, and I wish I didn't have to install a rack. But as my name suggests, I ride a Krampus. With the big wheels and my short legs, there's not enough room for a seatbag. Not only that, but the small triangle on my frame means not much storage in the frame bag. So my current design for the seat bag is 1500 cubic inches or 24 liters, unstuffed. That gives me enough extra storage for more water and more food if I have to go days between resupplies.

Thanks for any suggestions you might have.

[flanksteak]

I'm curious to see how you decide to attach the bag to the saddle. I'm working on a similar bag (even inspired by the same blog post!) and that's the part that has me stuck. Here's a similar bag I found that uses a fairly standard attachment method, not sure if it's as stable as the Carradice quick release though: http://oceanaircycles.com/2011/05/19/saddle-bag-no-001/

[Krampus Snail]

I don't like the Carradice attachment system. I particularly don't like the dowel used for a stiffener: in my experience, the screws that hold the dowel pull out, and the dowel also causes abrasion holes at its ends. Also, I don't use a saddle that has loops.

But I don't have any great suggestion to replace it. My current theory is to attach the bag to the saddle rails with webbing sewn to the bag. Since the bag won't be hanging from the saddle- rather, it will be sitting on the rack- I think that will be strong enough. Then in lieu of the dowel, I'll use a piece of 1/4" closed cell foam the width of the bag, and maybe 5" or so high. I'll sew the attachment webbing through the fabric and through that foam, and I'll probably sew the foam to the edges of the bag too. I'm hoping the foam will stiffen the bag adequately. I figure that in bike camping, the bag is going to be full, so the contents can do part of the work to maintain the bag's shape.

Instead of the Carradice-style side pockets, I'm going to use Leno mesh closed with a drawstring. That way I'll have a place to put my just-washed shorts and my wet towel. Dusty and dry is better than wet and moldy, I figure.

[CraigT]

I mount my Carradice bag on a Bagman support.  The support will mount on standard saddle rails.  https://www.benscycle.com/p-4151-carradice-bagman-qr-support-expedition.aspx?gclid=CKGz0rHSlsECFbPm7AodUzAAng

[Krampus Snail]

The Bagman doesn't work for my Surly Krampus. Not enough room between the tire and the saddle. Those Knards are huge; they have a 31.5 inch outside diameter.

[CraigT]

Hmmm.  The vertical drop on my Bagman is 6".  If you don't have room for that, I don't think you'll be able to fit a Longflap bag.  The Revelate Designs Pika has a similar drop, so I don't think that would work either.  You may want to consider Arkel's Randonneur Rack and Sherpack:  http://www.arkel-od.com/us/all-categories/randonneur-series/sherpack-backpack-bag.html. 

[Krampus Snail]

I have a Bagman. The one I have doesn't work on my bike; not sure of the vertical drop. However, with the Nitto Rack, I have successfully used a Nelson Longflap. It was OK, but I disliked that the bag doesn't attach to the rack, so it wanted to move and twist in unsatisfactory ways. My homemade bag will attach to the rack, like the Pedaling Nowhere bag.

[Krampus Snail]

I finished my prototype saddlebag, and I'm now testing it out. So far so good. It's staying on well. If we don't get rain this weekend, I'll take it on its first overnight.

I made it of 1000-denier Cordura, with XPac sides, and leno-mesh side pockets closed by drawstrings. To match the midnight blue bike with black parts, the bag is black with blue accents. It's shaped somewhat like a Carradice saddlebag, but with side panels shaped specifically for this rack and this saddle height. I wrestled over the idea of what stiffener to use, finally deciding not to use any stiffener other than the fabric, so this is a soft bag. The bag is two side pieces joined by the bottom/lid, which is one piece. The seams and edges are bound with one continuous strip of 3/4" grosgrain.

The bag attaches to the bike via velcro to the seat rail, and velcro to the back rack, as well as having two compression straps that wrap around the entire bag and hook around the posts on the rack. 

The top has a cuff of coated nylon closed by a drawstring, then a top flap lined in coated nylon. The top flap and the straps allow for over-stuffing the bag, as might happen if I just bought a lot of food, or I need to carry a lot of water for a day or two.

The bottom is reinforced with another layer of Cordura.

Proposed changes for final version:
* Use two velcro straps in the back instead of one. Sew on a loop of webbing between them to hold a blinky.
* Make the flap shorter.
* Move the compression strap attachments in the back down a couple of inches.
* Use a Microtex needle. The 100 Jeans I'm using punches right through the webbing, but it puts enormous holes in the XPac.
* Cut the compression straps shorter. I haven't gotten around to trimming the straps in the prototype.
* Sew the sides together wrong side to wrong side instead of right side to right side. I deliberately put the seams on the inside, to catch less mud, but with the seams on the inside the part where the flap joins the bag is a little crazy.
* Maybe sew on a stripe of reflective tape on the back. Or maybe not.

[bmike-vt]

Nice work!

[Krampus Snail]

Thanks.

[Adam Alphabet]

Design from scratch and building is no easy feat. Nice Work!