Backpack that can be fixed to the bike frame?

[drWalliser]

Hi, I'm looking for a bag that can be used as backpack and that can be fixed to the bike frame. The background is that I'm doing  mixed bike-and-hike tours in the Swiss Alps: first get by bike to some hiking starting point, then do some hiking without taking along the bike, then get back to the bike and drive home. I don't have a rack, and I don't like biking with a bag on the back...
One solution is to take along a folding backpack in a bikepacking bag, but maybe there are other solutions out there? Would it for example be feasible to replace the drybag of Revelate's Terrapin system by a backpack?
Thanks in advance for advice!

[THE LONG RANGER]

I do a few things, but they mostly start out with an actual pack.

One is to get a front rack, like the Surly 24 Pack Rack, and just use the backpack as your front bag. Works surprisingly well. Just tie the pack to the rack and be done with it. This is the pack I use:

https://ultimatedirection.com/fastpack-35/

The attached photo uses the, "just use the pack as the front bag", idea.

The other idea is to flatten the pack, and just tuck it within something like the Revelant Designs Sweetroll and take it out when needed. That works fine, too. I've also used that front rack with the Sweetroll and using both at the same time seems to be compatible enough.

This shows the, "Stash in a Sweetroll" idea: https://www.instagram.com/p/BWglQHDDbzO/

[bmike-vt]

Depending on your cockpit you might be able to use the Revelate Harness and tuck the straps in and cinch it into the harness, maybe bring along a piece of ground cloth or Tyvek and wrap it first, then tuck it in.

How much gear are you carrying? Enough for day hikes? Are you carrying mountaineering equipment as well - crampons, axe, rope, anything else?

[drWalliser]

Thanks for your feedbacks!
The backpack is only for day hikes - no mountaineering equipment. So a volume of 10 to 15 L should be sufficient.

[THE LONG RANGER]

Thanks for your feedbacks!
The backpack is only for day hikes - no mountaineering equipment. So a volume of 10 to 15 L should be sufficient.

Would a trailrunning vest work instead? You can find one with a total liter of around 15L, if you add up all the various pockets:

https://ultimatedirection.com/adventure-vest-4-0/

It'll stuff down into about nothing. Less than a puffy jacket.