Rack vs seat-post bag

[UtahGuy]

Big noob here.  Had plans to head out on my first bikepacking shakedown next weekend, but a dislocated shoulder just gave me some extra time to think about and fiddle with my kit, maybe some of you guys who have been there and done that want to think about it with me while I convalesce?

My squishy leaves me with no room for a triangle bag, so I'm stuck with a seat pack or rear rack (or a backpack on my back - Do Not Want).  I have a Topeak Beamrack I've used for commuting and had planned to strap a 8x16 drybag to it - is it worth ditching the rack for the lighter seat pack setup?  I'm concerned about a seat pack wobbling around back there and rubbing on my legs and generally driving me nuts.  On the other hand, I'd love to lose the weight of the rack, my pile of junk is heavy enough as it is.

Squishy with dry bag on rack:


Squishy with dry bag strapped up under seat:


Closeup:


For bonus points, is there a better way to secure that dry bag?  Set up like it is I get a little big of sway and it rubs my legs while pedaling.  Don't say "buy a Revelate/Ortlieb/Other Commercial Seat Bag".  I'm sure they're great, but that's not an option right now.

[offroute]

I don't think you'll do too much better attaching the seat bag without modifying the bag some (sew on daisy chain, etc.). Or get an off-shelf bag. I think your concerns about wobble/rub are justified with a bag as large as, and shaped like, the one you're trying to use. Yes, I would steer away from the rack pictured.

There's a boatload of room in that triangle for cargo. Also under the down tube and above the TT. But if you can't afford a seat pack, I doubt you'll be able to afford any packs to fill those spaces space, or for having one sewn up.

Tools and time off cost money. Welcome to the luxury of bikepacking. Maybe sewing bags yourself is the solution.

[UtahGuy]

Maybe sewing bags yourself is the solution.

The thought had occurred, I'm no stranger to the benchtop thread injector.  A skinnier bag with some webbing loops to secure the straps better wouldn't be hard.

[UtahGuy]

Banged this out last night.  It's smaller and longer and a lighter weight ripstop than the other bags, so I jammed some HDPE inside it to help it keep it's shape.  Roll top closure on top, shock cord tabs on the backside, and 2" webbing underneath to protect against wheel rub and secure the straps.





I had imagined that I'd just snap the roll top around the seat post, but it didn't work out that way and I might need to come up with something else here.



Looking at it, I don't know that I like the execution as much as the idea.  I have a grip of that tan ripstop, maybe I'll turn this into a handlebar bag and take another swing at the seat pack.

[offroute]

Looking good! Try a top tube bag then a frame bag, too. All issues solved