Tom Bihn Synapse 25

A heck of a bag for those who like a pocket for everything and everything in a pocket.

Note: Tom Bihn sent this backpack for review purposes.

My dad previously reviewed this bag, but my review of Tom Bihn’s well loved Synapse has been a long time coming. I chose the 25L because it is a more versatile size than the 19L and because I wasn’t confident a 19L bag would look right on my back. For those who follow the cult of onebag travel, this bag is nothing new as it has been among the preferred bags in that group for years.

Let’s dive into Tom Bihn’s Synapse 25 and see what is what.

The Basics

There’s four main variations of this backpack to know about: the 19L, the 25L, ballistic nylon, and dyneema. But wait, not all dyneema is the same, the dyneema you are thinking of is likely Dyneema Composite (aka Cuben Fiber) where’s this Dyneema is like super thin and strong nylon.

For this post I am talking about the 25L in black ballistic nylon. I have tried enough Dyneema bags from Tom Bihn to say that I really like their Dyneema and you should opt for that variant of their bags if there is a color of the bag you like with Dyneema. It is much better and lighter to use, but will telegraph more what is inside the bag.

Ok, back to this Synapse: the idea behind this bag is to make something versatile, but highly organized. There are six compartments, and seven freaking zipper pulls. But that’s also misleading, because there’s actually more than that. There’s three pen slots in one. A pouch area in another. And a big ass pouch in the big ass main compartment. It can be, and at times is, a bit overwhelming.

What’s also key to note about this bag is two additional options which I am going to assume are must buys, and I used the entire time. The first is a ‘Cache’ which is Tom Bihn’s nomenclature for a padded laptop sleeve. Yes the bag doesn’t come with one, so get a Cache to clip in. The second is the optional Frame Sheet, which should not be optional — it is great.

Who It’s For

I do think there exist more people who want a bag which has a place for all their stuff, than there are people who want one big spot for everything. That is to say, then, this bag seems to be designed for most people.

Organization is hard for many people (Marie Kondo basically has a career because of this universal truth) and so people want help and this bag is designed to help with just that. It can be overwhelming to people who really like to customize where and how things are stored, adding your own hacks to bags. However for those who have no desire to think about adding organization to a bag, but they want a good spot for their water bottle and chargers and stuff, welcome to the Synapse.


I packed up for a 3 day and 2 night work trip with just this bag and used it at my feet on the plane. You’ll need to brace yourself here because I have nothing but overwhelming praise for traveling with this bag.

It fits delightfully at your feet with ease. Something other bags can struggle with. I literally never ran out of space, and I think that is a first for me in quite some time. All of the highly organized and accessible pockets meant that it was really easy to get what I needed and when I needed it.

Just perfect for travel. Even the comfort was exceptional on my back (though I did need to reshape the frame sheet in my hotel, but that took 1 minute to do). The straps and materials won’t wear on any of your finer clothing and make for a good experience all around.

Daily Use

I did not, however like this bag for daily use. I carry a smaller kit of gear and found it harder to find which pocket something was in during my trips with the bag to the coffee shop. I also felt like the bag was just too large for me on a daily basis.

I know plenty who use these daily, but the size and amount of pockets (which make the bag great for travel) hindered the bag in daily use for me. What was hard for me is moving new kit in and out of the bag was a chore, because I had to take stuff out of pouches to fit them into designated areas in the bag. It is not very hot swappable.


Some things of note:

  • When empty the bag can have trouble keeping a full water bottle from moving about if it is in the water bottle pocket.
  • The lack of a padded bottom will make you think twice about tossing in any electronics which are not in a sleeve. Making it hard to travel with many larger devices at once.
  • The straps are comfortable, but they do not make weight disappear. I stood with the backpack on for 2.5 hours straight while waiting through flight delays. I was fine, but I wouldn’t say I didn’t feel it.
  • There’s too many zippers and they make too much noise. I put the cord zipper pulls on from Tom Bihn, but I would rather cut the metal zipper tabs off. It’s too much noise.


I really think this is a great travel bag, and honestly the backpack most people should get. But, probably not the people reading this site. If you still read along with my backpack reviews, then you are likely to prefer some other options. There’s basically nothing wrong with this bag, and a ton of things it gets right.

If anyone asks me which backpack they should get, I’d tell them the Synapse unless they gave me reason to recommend something else. It’s a backpack you can toss on in just about any scenario and be perfectly happy with.

Additional Notes

A few more things that don’t fit in well I noted while testing the backpack:

  • Tom Bihn’s new Cache design is great. It works in either orientation and the zippers make it easier to get your stuff in and out. Very happy with that.
  • The front bottom compartment is killer for jackets, I was able to stuff my Proof Nova jacket in that spot which gave me very easy and fast access to the jacket when leaving buildings. And it made it fast to stow the jacket when I got to TSA.
  • The water bottle pocket is like a custom home for my 40% mechanical keyboard, how cool is that? It’s fine also for a water bottle, but keyboards!
  • I forgot to close the million zippers on several occasions. Nothing feel out, but I always feel like an idiot when someone points that out. It happened a few times, and I have not experienced that with other bags. There’s just so many of them.

For me, this isn’t a bag I’ll regularly go back to, simply because I prefer a different ‘one big area’ type of bag design. It did really well traveling, but outside of the airport, I was less enamored with it. At the end of the day, it is not a bag that I have reviewed before because I knew I would struggle with the amount of pockets and organization. And on that thought, I was right.

Where I really misjudged this bag is on how well it worked for me when traveling. That was impressive.

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