(Pocket Sized) Messenger Bag Anti-slide Strap




aka the Pocket Sized Messenger Bag Spatial Orientation Stabilisation Device, or PSMBSOSD

If, like a large percentage of the population of Instructables, you wear a messenger bag and ride a bike, you'll be familiar with the problem of the bag slipping off your back and ending up under one armpit as seen below. This is a pocket-sized solution that you can quite easily make for free, or for at most a few quid. This is also my entry for the Pocket Sized competition.

Step 1: Materials

The Pocket Sized Messenger Bag Spatial Orientation Stabilisation Device, or PSMBSOSD, was inspired on one of my bike commutes to work that I could hook the strap of an umbrella in the side pocket of my bag over the strap adjuster and keep the bag in place. Having just read about the Pocket Sized competition, I pondered the idea on the ride home and came up with this by the time I arrived.

You will need:
- String or webbing, about 50cm/20" should be enough
- Two key clips (you could get away with one but it would make the PSMBSOSD slower to assemble)
- A split ring (again, not entirely essential- you could replace with a small amount of string or thread)
- A messenger bag
- Optional- a credit card sized card, sturdy business card or just a rectangle of flat plastic

- Scissors
- A lighter (if you are using synthetic string and want to seal the ends)

Step 2: Preparing the Patient

To prevent the bag slipping around, we are aiming to attach one end of the strap to the middle of the strap, and pass the attachment under the armpit. Note- I believe most right-handed people wear their bag the other way, so if you normally have the strap over your left shoulder you will want to attach to the left-hand side of the bag, so should mirror the following instructions.

Attach the split ring to the bag at or around the point where the strap is attached to the bag. You can just poke two small holes and thread the ring through- the nylony fabric this bag is made of won't unpick if you do that, but YMMV (Your Messenger-bag May Vary).

Step 3: Start the PSMBSOSD

Go boy scout style and tie one end of the string to the key clip you have chosen to be the bottom one. I chose the blue anodized one to go at the top because it's larger, opens more easily and looks funkier :)

If you are only using one key clip, you can tie a loop in the end of the string and feed that into the split ring or just tie/untie the knot every time you want to attach or remove the PSMBSOSD.

Step 4: Do You Measure Up?

Attach the clip to the split ring, put the bag on and measure how much string you will need. The string should run loosely (but not excessively so) from the bag to the strap, and meet the strap at approximately 90 degrees, in the rough area of your sternum (breastbone).

Step 5: Knot Again...

Tie the second key clip to the string at the point you determined in the last step. Optionally cut and melt the string- I didn't because I didn't want to waste a perfectly good shoelace :)

Step 6: You're All Done!

To operate the PSMBSOSD:

Clip bottom end to split ring on bag, put on bag, pass top end under armpit and loop around bag strap, and clip top end to the string to form a loop.

The PSMBSOSD has been rigorously tested on at least two of my commutes to work over a combined urban/extra-urban cycle of approximately one mile. It prevents the bag from slipping.

Step 7: Enhancements


Well, to justify the Pocket Sized entry you have to be able to put it in your pocket, and if you put a length of string in your pocket it gets tangled or ends up dangling out. That's why I invented the Handy Anti-Dangle Tangle Preventor, or HADTP. To make a HADTP, take your gift card/library card/business card/rectangle, and cut a triangular notch about 1cm deep into each of the short ends. Wrap the PSMBSOSD around the HADTP, and secure the ends together. This has been exhaustively tested by putting in my trouser pocket and jogging up and down the stairs- when I took it back out it was tangle- and dangle-free.

Also, the strap length adjuster on my bag is in just the right place to stop the PSMBSOSD from sliding around. If your bag doesn't have this handy attribute you could sew a couple of buttons or studs onto the relevant part of the strap to stop this happening.

If you made yours out of webbing rather than string, you could incorporate those pinch-release buckles, because everyone loves those things, and then you could attach/release the PSMBSOSD even more easily. They can often be found on unwanted or charity shop-bought bags, or on free lanyards from corporate events and games expos, etc.

OK, so if you've read to this point I guess you liked (or just tolerated) my Instructable. I've told people off for asking for competition votes so it would be hypocritical of me to do so here, so I'll just say this is an entry in the Pocket Sized competition and my first competition entry to date.



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    11 Discussions


    7 years ago on Introduction

    THis could also be accomplished with a small leader running from the main strap to a clip on your belt.


    7 years ago on Introduction

    and there me on me boike thinking that my messenger bag looked cool right up to the point where it turned left for me. This is one instructable I will be carrying out tomorrow

    Nice fix! You could even run (or continue) another string over your other shoulder and attach it to the bag at about the same point. You would have a sort of "X" of straps over your chest. Only downside I guess is it starts feeling like a backpack.


    cool, but why not just another one of those black straps that come with the bags


    10 years ago on Introduction

    I'm a big guy, and I'm not sure of the physics, but I think that it's even harder for me to keep a messenger bag on my back, probably my roundish shape, lol. Your solution is simple, elegant, and effective, and bonus, it's portable and deployable. I love it!

    I like it. The problem that I have more often is that when I run, the little jacket that protects your shoulder from the strap slides around. I think that could easily be solved with a safety pin, though.

    1 reply

    11 years ago on Introduction

    Nice job! Bring about 50 or something, then you have a lot. :P But you don't have 50 pockets...