I've long wanted a back bike rack bag (say that 4 times fast) that was also convenient as a messenger-style bag.
I have a couple of Ortlieb back bike rack bags that I bought when I first started bike commuting regularly. I think the clipping mechanism is ingenious and the bags are very solid, but the bags became annoying once I took them off the bike. Also I had found out that I didn't really need two.
Separately I came across this bag last year, and found it excellent in many other ways. Solidly built, well thought out, plenty of pockets, and even a fun reference to the fake institute of higher dark learning that features in many H. P. Lovecraft stories, "Miskatonic University".
Gradually it dawned on me what I was leaning towards the whole time: I could just make my ideal bike rack/walking around bag, with parts from my spare Ortlieb bag.
It worked out much better and easier than I expected, to the point where these two particular bags just seemed ideally suited for this merger. This could probably work for just about any bag you'd like to have hanging off your bike and also off your back. But the unexpected benefit of the Miskatonic bag was the secondary flap that can go right over the bike rack clip, to keep it from digging into your side when you're walking around.
This took me about 2 hours total time, and I expect people who are more used to working with clothes and bags could do it in less.
- 1 Miskatonic University bag, or similar
- 1 Ortlieb pannier AKA back bike rack bag, or similar
- 1 set Dritz heavy duty snaps or similar (optional)
- 1 power drill
- 1 3/8 drill bit
- 1 regular Phillips screwdriver
- 1 pretty small regular screwdriver
- 1 pair pliers
- 1 sharp knife
- 1 hammer (optional)
- 1 plank (optional)
Teachers! Did you use this instructable in your classroom?
Add a Teacher Note to share how you incorporated it into your lesson.
Step 1: Take the Rack Clip Off of the Ortlieb Bag
You trusty Philips screwdriver should do for this. Of course, also keep all the parts you're removing in a single place so you won't lose any.
Once you have the main top pieces off, the other screws holding it together will require a small regular screwdriver.
Some of the screws were new to me and I thought they might be Torx, a format that basically exists to make it harder for people to unscrew things. But it turns out they were Pozidriv, which is probably why a small regular screwdriver was sufficient for this. I also found myself using pliers on the back parts of the screws, to hold them still as I unscrewed them from the front.
Step 2: Put the Rack Clip's Backing Plate on the Back of the Miskatonic Bag, and Mark the Holes
Pretty self explanatory. If you've unscrewed everything you should easily be able to pull the backing out.
Lay it on top of the back of the Miskatonic bag, place it where you think it should most go.
Then poke a sharpie through the Ortlieb backing plate onto the Miskatonic bag, to mark where you're going to drill in the Miskatonic bag.
Note: when I originally did this, I didn't realize I had put the plate so that the bike rack clip would partly cover the Miskatonic bag's velcro strips. The result of this is that the bag's secondary flap would flop loose. This ended up leading me to a solution I liked even better, that I include in the next couple of steps.
But if you want to potentially save a step, you can try placing the plate so that the secondary flap will reach over the clip to reach the velcro that the Miskatonic bag comes with. This could also require removing some of the bottom of the Ortlieb backing plate. This could also mean the bag would ride a little higher on the bike's back rack, which could be cool.
If you do that and like it, you could just skip ahead to putting it all back together.
Alternately, put it wherever you want and get ready to put on snaps, which I really like for how they worked out.
Step 3: Drill!
Drill the holes that you marked into the Miskatonic bag. This bag has a plastic plate of its own in the back, for stiffness. Drill through that, taking care to not go to far into the rest of the bag. It's probably a good practice to put a plank of wood behind where you're drilling to stop it from going further into the bag. I just held the bag with my hands and get the cloth away. Do as I say, not as i did.
Step 4: Add Snaps to the Secondary Flap, to Cover the Bike Rack Clip When Not in Use
So I got some heavy duty snaps from a crafts store. "Dritz" was the brand I bought, but I expect any similar brand will do. Dritz also had some videos.
Above is the YouTube video I watched about the overall process of putting in snaps. I have to say I found this interesting by itself, having used snaps in clothing my whole life without thinking about how they were put in and put together.
Putting the snaps into the back of the Miskatonic bag took a bit more work than expected--really the most work of this project. The heavy duty snaps weren't quite long enough to go through both plastic plates. So I put them through the first one Miskatonic bag's plate. I also cut into the bag's cloth that covered the backing plate, and widened the drilled hole on the top side. Then I put a wood board behind the snap so I could properly hammer it into place.
This is also a good time to remove the velcro strips on the Miskatonic bag from the back and the secondary flap, as you likely won't be using them now.
Step 5: Screw the Plate and Rack Together Into the Miskatonic Bag
Again, pretty self explanatory. Put the Ortlieb backing plate on the further side of the Mistakonic bag's own plate, and put the screws and backing plastic knobs in. Be careful not to strip the screws.
Note: above pic doesn't show the snaps. as this was taken before I realized I wanted a way to cover the clip assembly, or it could dig into my side as a I walked.
Step 6: Voila!
And that's it!
It's been great so far. One other minor detail has been making sure the Miskatonic bag's side zipper doesn't come loose in transit. My workmanlike solution has been to just tie the loop around the top of that zipper to another loop from the front zipper.
I've commuted daily with this for a week now. Looks great, words great, and great compliments so far. If I did this, I am absolutely sure you can too.