The Synapse 25 Frame Sheet with the pull-tab open to show the t-bar behind the aluminum stay. The Synapse 25 Frame Sheet A close shot of the Synapse 25 Frame Sheet installed in the rail loops of a Synapse 25. The Synapse 25 Frame Sheet installed in a Synapse 25 under a Cache. The Synapse 25 Frame Sheet installed in a Synapse 25. The Synapse 19 Frame Sheet with the pull-tab open to show the t-bar behind the aluminum stay. The Synapse 19 Frame Sheet A close shot of the Synapse 19 Frame Sheet installed in the rail loops of a Synapse 19. The Synapse 19 Frame Sheet installed in a Synapse 19 under a Cache. The Synapse 19 Frame Sheet installed in a Synapse 19.
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Synapse 19 or 25 Internal Frame

$32.00

Optional internal frames with aluminum stays designed to work with any generation of Synapse 19 or 25 that has rail loops.

Description

Optional internal frames with aluminum stays designed to work with any generation of Synapse 19 or 25 that has rail loops.

We present for your use these optional, removable internal frames with aluminum stays for the Synapse 19 and Synapse 25 backpacks. 

The frames are made of die-cut .055” thick High Density Polyethylene (HDPE), with a nylon webbing sleeve sewn down the center that encases a 1” / 25mm wide 6061 aluminum stay. 

We’ve bent the stay to a generic spinal curve; we recommend you re-bend and/or adjust the curvature to best fit your own back (see here for instructions). If you just want a frame sheet, the stay is removable, though it's worth noting that a frame sheet sans aluminum stay does just about nada when it comes to shifting the weight of the pack onto one's hips. (Read more about that here in our Guide To Backpack Frames.)

Because the Synapses were not originally intended to accommodate an internal frame, they weren't designed with a way to attach one; this required us to make some modifications to the frame design. We took advantage of the loops for the Cache tablet/laptop sleeve ​at the top of the packs to retain the internal frame: a clever “T” bar holds the frame in place relative to the loops. The lower edge of the internal frame floats free in the Synapses—we’ve found this isn’t much of an issue as the contents of the bag tend to hold this lower extreme in place. Please note: your Synapse must have rail loops in order to use these new, optional internal frames. If your Synapse doesn't have rail loops, you're welcome to try using the internal frame anyhow; let us know how it works for you.

If you order the internal frame on the Synapse 19 or Synapse 25 pages along with the pack itself, it will come pre-installed. If you order the internal frame separately for an existing Synapse, or if you remove the installed frame and then want to add it back, take a look here: Video + Text Instructions On How To Install or Remove the Synapse Internal Frame

And don't worry: even with an internal frame in the Synapse, you can still use the very same loops to secure a Cache.

Once we engineered a frame for the Synapse 25, making one for the Synapse 19 was easy enough. You may be thinking: isn't an internal frame for a pack the size of the Synapse 19 overkill? One could argue yes and one could argue no, but really it's up to the person using the pack. 

And, of course, we tested both sizes of Synapse with the internal frame on over a hundred miles of day hikes. Our take, after testing? The pros and cons of the frames resonate with our experience and the reasons listed below. 

Benefits of an Internal Frame

• On bags with a webbing or padded hip belt, the vertical stability facilitated by an internal frame with an aluminum stay can help to lift some of the pack’s weight on to one's hips. 

• It creates a hard back panel that prevents less-than-carefully packed objects like a thermos or DSLR from poking one in the back. 

• It can prevent an overstuffed bag from barreling out against one's back.

• To some folks, a rigid frame against their back (with padding between the frame and their pack) just feels right. 

Why You Might Not Want To Use a Frame

• A frame adds weight to a bag. Our Synapse 25 Internal Frame weighs 9.6 ounces / 272 grams and our Synapse 19 Internal Frame weighs 6.9 ounces / 195 grams. In many cases, you can forgo the frame and achieve similar benefits with careful and thoughtful packing. 

• The rigidity offered by the internal frame becomes a liability when you’re squeezing your pack into the overhead compartment or under the seat in front of you, or when you’re packing your backpack inside other luggage. That's a reason it's nice to be able to remove the internal frame when you want to.

• Some folks simply prefer the feeling of a frameless or soft-back pack. 

For more on our philosophy and experience regarding internal frames, please see our Guide To Internal Frames.

Materials

.055” thick High Density Polyethylene (HDPE)
1” / 25mm wide 6061 aluminum
Nylon webbing

Specs

Weight:
Synapse 25 Internal Frame: 9.6 oz / 272 grams
Synapse 19 Internal Frame: 6.9 oz / 195 grams
Dimensions:
Synapse 25 Internal Frame: 9.7" (w) x 17.9" (h) / 247 (w) x 455 (h) mm
Synapse 19 Internal Frame: 8.2" (w) x 15.2" (h) / 208 (w) x 385 (h) mm
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Sewn in Seattle

Our bags are designed and sewn right here in Seattle, Washington, U.S.A.

That allows us to be control freaks in the best way possible; we have direct control and oversight of the quality of our materials, our products, and the jobs and working environment that we help create. It also offers us a unique spontaneity: when we have an idea for a new product or accessory, we can design it, figure out how to build it, add it to our website and be ready to ship it out our front door all within just a few weeks. How cool is that?

Intrigued? You can find out more about the unusual way we do business on our Company Philosophy page.

THE BIHN Guarantee

Everything you buy from us here at TOM BIHN is satisfaction guaranteed. We’ve been in business for over 30 years and we stand behind what we make.

If something goes wrong and it's our fault, we'll fix it for free. Repairs due to normal wear and tear or due to other things that are not our fault will be performed, when possible, at a reasonable charge right here in our Seattle factory where your bag was made. Defects in materials or workmanship are uncommon and almost always evident while the product is still new. Keep in mind that bags and packs are often subject to extreme wear in everyday use: do not expect them to last forever. Only true love lasts forever! You can expect a TOM BIHN product to give years and years of hard service.

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Rated 3.8 out of 5
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average rating 3.8 out of 5
Based on 6 reviews
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67% of reviewers would recommend this product to a friend
Quality
Rated 4 out of 5
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Reviewed by Noah
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Rated 5 out of 5

The McRib of Tom Bihn items

The S25 frame is like the McRib. It only comes out every once in a while. Waiting for a 7 a.m restock, I sit quietly. It sadly turned into fishing for me. The thrill of the catch. Once I finally got it on the hook, I threw it back / returned it for whatever reason. I have not been able to get one since. My mistake. If you can get ahold of a frame, I recommend it. It works well as far as keeping items from poking you in the back, and adds structure

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Reviewed by Zachary R.
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Product Standouts
  • Comfortable
  • High Quality Craftsmanship
  • Durable
  • Great Gift
  • Made in USA
Rated 5 out of 5

Adds structure and comfort

This made the backpack much more comfortable and also reduced fatigue a bit on longer trips by distributing weight. Not very difficult to install. Makes it slightly more difficult to stand the bag up on its own. Also tougher to fit in small spaces, of course. I use this for my hiking/traveling Synapse 25, but not in my work 19 because I have to squeeze it into bins/cubbies more often.

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Reviewed by Heather A.
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  • Comfortable
Rated 5 out of 5

Frame

Important. With a little bending this baby keeps my new Synapse 19 off my sciatic, something no other backpack could do before. This is a two-fold success - a back pack perfect for a short girl with a short torso and a frame to ensure the frame stays off the painful parts of my back. Success!!

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Reviewed by Jason E.
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  • Comfortable
  • Durable
Rated 4 out of 5

Nice

Quality-wise, nothing at Tom Bihn can be beat. I definitely appreciate the rigidity of the internal frame. It definitely protects my back and keeps things inside the bag in a good order. It didn't really do as much for me as far as letting the bag stand on it's own, but that wasn't a huge downfall for me. Overall, I do think it's a bit overpriced for what it offers, and it should really be included with the bag itself. However, I don't regret buying it, and I definitely use it everyday.

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Reviewed by Michael G.
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Rated 1 out of 5

Didn’t work

I thought this would connect to my Synapse 25, but I guess I can only slide it into my bag, unattached, which doesn’t suit my needs. I love TB, but this one was a miss.

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Rated 3 out of 5
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TOM BIHN

Hi there! I'm sorry your frame isn't working well for you! I just sent you an email to ask a couple questions to see if we can get this figured out :)