How to "stiffen" toptube bags?

[Adventuresbycycle]

Hey everyone,

I'm new to the MYOG, but I'm really enjoying learning how to make bags. I started off with a toptube bag, following the instructions and pattern from Tim at learnmyog.com

However, I've just finished the bag and taken it for a ride and I feel like it needs quite a bit of extra stiffness on the base and side panels to stop it from sagging and collapsing when I put things inside!

I've already bias taped the inside seams, and I'm using a 500D PU Coated Nylon waterproof - so I'm not sure what else I can do?

Any ideas or tips would be brilliant - thank you!

Sam

[Adam Alphabet]

Try here for some ideas..

http://www.bikepacking.net/forum/diy-make-your-own-gear-(myog)/top-tube-bag-what-foam-or-plastic-for-structure/

[camnrtn]

I went through this recently and ultimately decided to use thin foam (1-2mm?) recycled from the back panel of a backpack, that provides plenty of rigidity for me. It's most important on the side panels and front (facing you) and back (facing stem) pieces, as opposed to the base. You could sew some inner tube to the base to stop it moving against the frame. Also, 500d cordura has little structure, whereas something like xpac naturally keeps it's shape better. Long and low design will flop around less than tall or fat design too. Just my 2c