I realise most cyclists will do anything to avoid wearing a pack, but I find them almost mandatory (for me) on really long rides/gravel races and bikepacking. Just seems easier to use a bladder and I find I drink more especially when on technical terrain. I've tried using a bladder in my frame bag, but I can't get along with it. I've read a couple of other threads here relating to packs, but hard to find actual recommendations on specific models.
For running I use an Ultimate Direction vest, and that may be the best bet for me, but I don't really love them on the bike - probably because they're designed for someone upright. I don't really need to carry anything other than a 2L bladder. EVOC do one that looks OK - any other suggestions please?
I just did an 80 miler with a Camelback Rogue (1.5l). I didn't like the way the hose snapped into the shoulder strap. It was restricting flow when it was clipped in, and flopping around when it wasn't. I was at race pace, so I wasn't able to clip it in/out when I needed it. I ended up buying a Osprey Katari 1.5l, which uses a magnet to secure the hose to the shoulder strap. I'll be using it for the first time Sunday. It's very minimalist and I only anticipate using it for water.
