Reviewed this before but wanted to update. I was finally able to get out for a short bikepacking, solo camping trip. Was only two days, but 5-6 hours of riding each day, and it happened to be a weekend where an atmospheric river came through the region. Was thinking of cancelling, but went ahead and rolled with it. Nearly constant rain during the ride and even through the night while my bike was out in the open and I only had enough things to cover the saddle and handlebars, so the bag was mostly exposed throughout. The only moisture I could find inside the bag was from items I put inside it that I hadn't completely dried off. I was truly impressed. If only my rain jacket and shoe covers had performed as well...
Had been looking at this for awhile, was given a gift card so finally pulled the trigger. Wish I had gotten it sooner! It's surprising how much can fit in it. Zippers function smoothly, and don't jingle annoyingly like some other bags I've tried. Outside pockets are functional, and I love the amount of attachment points provided. Haven't used in heavy rain yet, so can't speak to water resistance. Was planning on only using it on my winter bike, which also has a rack and handlebar bag that I use for commuting and hopefully some bikepacking starting this year. But on sunny days I like to use my nice road bike for commuting just so I can ride it more, but it has no rack mounts so it requires wearing a backpack, and when loaded up my back can get sore. Adding this frame bag to my nice bike has been great since I can transfer quite a bit from my backpack and keep my back happy even if I take a longer route home. Also allows me to keep my phone and tools more accessible if I need to get to them quickly, and I'm excited to try putting a water bladder in for long adventure rides.
I put this frame bag on a Trek Stache 9.7 size small. I got the small bag and it fits snugly. The exandable nature of the bag is good, and when expanded, it fills the main triangle completely. I can put in my frame pump, a thick pair of winter gloves, tire levers, multitool and a tube. That pretty much fills all the space. Attacment is easy, although the front and rear belts have a long floppy end that needs to be tucked in somewhere when the are tighthened up. I just wrap the loose end around the frame and tuck in the strap. The bag has performed well in 0 degree winter weather and so far the zippers have worked fine. It does not get in the way of peddling either. S
This is a really nice bag, but even the Medium-sized version was too big to fit my Rockhopper 29er. The price was very good - I saw the same bag in a retail store for 50% more.