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Bottom of the Synapse 25 folds up

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    Bottom of the Synapse 25 folds up

    Hi, I recently got my S25, and it's great, but I noticed that the bottom of my bag folds upwards when the straps are being used, which kind of makes it a little uncomfortable against my back, since I can feel the folded part pressing against me.

    Is this a common thing for Synapses (or S25), and are there any suggestions? Just curious.

    I'm on the Ballistic 525 with Halcyon interior.

    I didn't have that issue when I owned an S25 (Halcyon if it matters). It does, however, look like you have the shoulder strap cinched down all the way and that it may be pulling up on the lower attachment point creating the ripple. I'm not sure if it's a matter of there not being enough shoulder strap to allow the pack to lay flat.


      My back is short and I have had similar issues with my S25 buckling at the bottom. It doesn't tend to do this when I have my Freudian Slip in it (thanks, Ilkyway!) but it is possible that you might find an S19 more comfortable for your height. I have yet to try one (I love the bottom S25 pocket too much) but I know it would sit better on my back.

      Sent from my iPad using Tapatalk


        I love my S25s but they do not have enough structure. Period. They need a frame sheet.


          Hi @chungliwen!

          My immediate thought is similar to Muni_Jedi's. It looks like that is caused by the backpack straps being pulled as tight as possible, and causing that ripple in the lower portion of the back panel. How does your Synapse fit if you loosen up on those straps some?

          It is possible that the bag is a little large for you, we find that the Synapse 25 works well for most folks, but it could be too big. It is also possible that you're wearing the backpack a little higher on your back than is necessary, so you might experiment with loosening those straps.

          Different folks find different things comfortable but a good, general rule of thumb is that the spot where the backpack strap curves over your shoulder and meets the bag should be right around your shoulder blade. And even after years of wearing backpacks, I always find it helpful to give my backpack straps a little bit of loosening every time I take the bag off, and give it a little tightening tug to find the sweet spot each time I put the bag on. You might try something like that to help find your sweet spot

          Of course, we're happy to help brainstorm further on this directly too. You're welcome to call or send a note to [email protected] if you'd like in situations like this.


            Hi Guys,

            Thanks for the quick feedback.

            I do wear my backpack slightly higher than most (I think). Picture below. My usual strap length/adjustment. Feels just about right, or maybe slightly too long for me, but I'm ok with that. I'm 172cm (5.64 feet) tall, just for reference.

            Though I just undid the strap and let it run pretty long just to test, and it still folds that way. Sorry for the crappy picture. Hard to hold it away from me and take a pic. Picture below.

            I kind of agree with @Cristina and @SIM that perhaps a frame sheet (or Freudian Slip which should have the same effect) might be a solution. Or maybe stuffing a jacket at the bottom. I'll go experiment a bit when I have some time this weekend.

            Thanks @MikeV for the offer for me to email support. I'll experiment a bit more first and enjoy the discussion here, then maybe drop a follow up email. I haven't emailed in yet because I'm just guessing it's just due to the bags design. Not a deal breaker, so no big deal. Just curious as always.



              I haven’t tried the S25, but I did return a SA because of a backside issue. Coincidentally, the bag I chose does have a framesheet, which I quite like.

              (I passed on the S25 due to lack of interest in pockets.)


                This additional info is interesting to see @chungliwen. In the photo of you wearing the bag — are the straps cinched down to their maximum shortness in that photo? My guess is that the Synapse 25 remains bunched because its foam became creased when the straps were initially pulled really tight. It doesn't look normal, and is not part of the bag's design.

                You and I are similar in height- I'm about 175cm (5'9") and I've been wearing a Synapse 25 around the factory a lot of the morning. I find that I have about 5 inches of the backpack strap between the buckle and where it connects to the bag.

                Here’s a photo of me wearing the bag how I would normally fit/wear a backpack:

                Click image for larger version

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                Here’s a photo of me wearing the bag with the straps cinched to their maximum shortness:

                Click image for larger version

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                This morning, I set out to replicate what you’re experiencing. First, I put on an empty Synapse 25, and tightened the straps to their maximum shortness; I was not able to recreate the fold as seen in your photos. Next, I fully packed the Synapse 25 (using packing methodology as outlined here: Packing for Ideal Weight Distribution and here: How to Pack a Backpack) and wore it with the straps tightened to their maximum shortness, and no fold. Next, I left the main compartment of the Synapse empty, but packed the front pockets with heavy items, put the pack on, tightened those straps totally down, and no fold… but, I did see how the back of the bag caved in and a fold formed when I wasn’t wearing the bag. However, that fold curved outward as opposed to inward. So, I wasn’t able to figure out exactly what’s going on here, which is a little frustrating as I was pretty determined to recreate your photos!

                Do you happen to carry heavy objects in the side pockets or water bottle pocket, or maybe a laptop in the internal open-top pocket, but not much else? That could potentially be part of what’s impacting the bag.

                Ultimately, one shouldn’t have to cinch backpack straps down all the way in order for a pack to fit comfortably, and if that’s what’s happening, the pack itself might just be too tall or not the right fit. And, of course, we want you to have the most comfortable pack and the best carrying experience possible and not have to go to extremes to make it work. I’ve reached out to you via email to see what we can do to figure this out together in the most efficient way.

                Now, on to a different topic (you’ve got me on a roll here…..)

                There is quite a lot to think about regarding internal frames and frame sheets. It could help with some of what you're showing but it's not, at least in our view, what they're designed to do. There are two elements to internal frames in how I look at backpacks: a stiff panel to keep things from poking into your back, and a stiffener- most often a metal stay, to help anchor the weight of the bag. When a backpack with an internal frame is used with a hip belt, that is the best way to anchor a heavy load to the hips. And it's really tough to anchor significant weight to the hips without some sort of stay. In most of our bags, we rely more on folks thoughtful packing to achieve comfort, as is true of most day packs on the market. That means packing clothes and jackets against your back and your thermos or camera in front of that clothing. That is critical when using a bag like the Daylight Backpack, and certainly helpful when using a bag like a Synapse.

                On larger packs, more intended for extended day hikes or overnights, an internal frame can really shine. Our Guide's Pack and Hero's Journey both have internal frames with aluminum stays and are the ideal chooses for more extreme outdoor pursuits, partially for this reason. They protect from the poking, and allow you to comfortably transfer the heavier loads more securely to the hips. Even so, internal frames are a bit of a hot topic these days. Lots of really fast, long distance hikers choose packs without a frame sheet or stays in an effort to save the weight. Hiking 20-30 miles a day, for days on end, puts a lot of strain on the body, and anything you can do to lessen that is valuable to some folks. Still other folks use really large, and by some standards- heavy backpacking packs for these pursuits. They value ultimate comfort over saving the few ounces or pounds. Most folks find their happy place in between these extremes.

                A bunch of us around here are pretty active hikers and outdoors folks. Darcy regularly goes on 15-20 mile dayhikes and carries a variety of packs, depending on remoteness, camera gear, and time of year. She comfortably carries a Synapse 25 or 19, and the Guide's Pack gets plenty of use too (she's 5'5"). I hike with a Synapse 19 quite a lot, and use a Smart Alec some if I need that much gear. Most of the time I'm a lighter style hiker/runner. It's not uncommon for me to use a really light and small, non-TB (shhhh!) running style backpack. Similar to Darcy, I routinely cover 15+ miles in my pursuits. All of this is to say different folks have different wants and needs in their gear. We offer a lot of great choices, and if what we offer isn't right, there are a lot of other great makers out there.

                None of this is to say we don't see value in internal frames. It's an idea that we've taken very seriously, and may offer at some point. Wouldn't it be great to offer a bag that you could choose to use that feature, or not, depending on your needs. Maybe one day


                  I have a Synapse 25 and find I occasionally get a similar ripple. I mainly use this bag for school, and find that a quick readjustment of some binders and/or whatever I have in the bottom pouch usually fixes it. I'm about 5'5" (I know, the S19 would fit me better, but I wanted the extra space) and also keep the straps cinched all the way up. I normally don't have much of a problem with it though. All that to say, is there a different way you could pack things to avoid this problem? Side note: when I have classes lasting all day, I take lunch with me and that bottom pouch is PERFECT for my lunchbox. It's a great fit and keeps it out of the way of my binders, etc so I don't have to deal with it when grabbing stuff out of my bag. Love that pouch.


                    What I have in the main compartment. Purposely wore a white shirt and tucked it in so we can see, lol.


                    Pics below is when I've lengthened the strap very long.

                    Video https://i.imgur.com/EWJzdNC.mp4


                    Personally, I'm not complaining, as I think it's more of the design of the bag, rather than a defect. I think as long as you put more stuff into it, it should keep its shape better.

                    I've put some items in below.

                    Sorry for the many pictures, and thanks a lot MikeV for reaching out. Will be in touch! Appreciate the great service.


                      So, I was reading through this yesterday and had my S25 in front of me and fiddled around a bit.

                      I, too, could not get my bag to behave like OPs. However, I was able to get this sort of "bulge" in the middle of the back portion. It was also a bulge outward, not inward. It seemed to be caused by having the front pockets heavily loaded which would bring the front of the bag downward and put unnecessary stress on that portion of the bag. But my bag is also Halcyon, which perhaps contributes to its ability to "behave" better since it's a thinner material that sort of adapts to whatever it's up against.

                      I was looking at maybe ordering a new 525 material bag and potentially selling my halcyon model, but this has me kinda second guessing myself. I'm curious if you ever figure out how to create this situation so I know whether I'd encounter it myself. I'm about the same height as you and tend to have the straps cinched down reasonably close to the closest setting (there's about 1.5-2 inches from their maximum cinch point


                        Just as another point of reference, I'm 5'7" with an 18" long torso, and my s25 in 525 ballistic does a similar fold when worn on my back. I daily carry about 8-10lbs which predominantly consists of a filled 32oz stainless steel water bottle in the bottle pocket, keys and wallet in the pocket below that and a 3dsxl, large Anker charger, and first aid kit in the main cavern. The pack overall is a bit too long for me and when worn and underpacked it slouches away from my body. I do use the 1" padded waist strap and the shoulder straps are not cinched all the way down. As a comparison, the s19 is a bit too short on me holds its shape better and would be comfier if not for the narrower strap placement. Overall I find the s19 to be a more sturdy feeling pack while the s25 feels more slouchy in comparison.


                          Here's my theory.

                          I haven't got the s25, but I do have a rough idea of the compartment layout. At the same time, I have previously gotten this "fold" with a previous bag (Lowe Alpine 45L). As I understand it, It's a combination of heavy items + lots of empty room. Theoretically, to recreate it you need the following requirements:

                          1. Bag with no inner frame/framesheet.
                          2. Bag with lower front pouch (like the S25).
                          3. Unusually heavy/metal item. Try a barbell weight. 5kg should do the trick. Insert it into the lower (not upper) front pocket.
                          4. Attach heavy laptop to upper rear area (e.g. using cache right against your shoulders). This should make the fold more pronounced. (edited a bit)
                          5. Wear backpack and cinch the straps tight (while wearing it).

                          What should happen is that the bottom part of the bag close to you (lower rear/main compartment) goes up due to the straps tightening and being empty. If the bag was empty, everything would just float up and ride closer to you. But the bottom part far away from you (lower front pocket) is still quite heavy and stays down. The front part tries to stay down. The rear bottom part tries to go up. The rear upper part tries to stay down (laptop). A fold develops.

                          In fabric backpacks that are flexible enough (canvas. And halcyon maybe?), the whole back kinda scrunches up a bit and it's not so visible. With harder backs, it (probably) just doesn't fold. With the S25 foam padding (or my old pack), the padding is just hard enough to keep its shape but bend at a single point.

                          However, this is based off the anecdotal data of a single previous bag (which I no longer own and have returned). Hopefully someone who owns the S25 can try this out.
                          Last edited by Lodd; 11-03-2017, 11:32 AM.
                          Western Flyer Black Ballistic/Island Halcyon


                            Ah, this makes sense. Basically the heavy part of the bottom is causing the bottom part to push against the middle and crunch together. Because the S25 has no structure on the back really it's the weakest link so to speak and that's where the stress is being placed at the end of the day.