Already have a rack & pannier and for this commute & bike I prefer a pack or messenger bag.

SO…

my office has changed and my gym situation has changed - I no longer have a permanent locker at my office campus gym. so I now need to carry a 15” laptop fairly regularly, toiletries, and work clothes and probably shoes (though I may leave a pair under my desk so I don’t have to carry them too often).

so I need a bag big enough to carry those things and some extra layers in the winter. And also probably be waterproof or fairly water resistant as I do bike when it rains.

I’ve never used a messenger bag before but am open to it.
I was looking at some pocampo and chrome industries bags late last night but didn’t get super in depth.

gimme your recs.

So far this one is leading the charge:
https://www.osprey.com/us/en/product...RADIALF19.html

Looks like a really nice bag and I always go for Osprey backpacks for my long distance hikes and wear there viper 9 for every day use.

A couple of a type I’ve been eyeing.
In your case, will a single top opening work?
Leather:
Berliner Bag

Similarly, but In canvas and has hooks for racks.
Tourbon

I commute with a backpack and have moved to larger, lighter ones over time. You don't need the comfort features of a regular pack that's intended for hiking because you're not hiking. Over time I've mostly come to cheap packs designed for packing in one of their own pockets for travel, the largest I can find, and you can't believe the specs as to how many liters any of them hold (volumes for backpacks are ALWAYS with every pocket and add-on--water bottle pockets, etc.--stuffed to breaking. Look at overall dimensions for the truth.) My current one came from Walmart for under twenty bux, but I see they no longer sell it. If you search Amazon for "packable backpack 40l" quite a few will come up. The only absolute necessity for biking, IMO, is a sternum strap to keep the shoulder straps where you want them. Though it's not good backpacking form, I often let the straps out all the way to keep my back from getting sweaty, which is the biggest disadvantage of using a backpack for commuting.

I tried a messenger bag and did not like it. It never wanted to stay where I put it for very long and got inconveniently bulky and round when loaded. My first small backpack was an expensive LL Bean and I don't use it anymore because it's too small and all flash, no go. Going cheap and simple is better, I think.

One example: https://www.amazon.com/G4Free-Lightw.../dp/B08LN11YRV
Whatever you get, read the reviews. For this one they're pretty good, but it might not fit your laptop. It's just an example of the type of thing you can find.

Nothing is waterproof. Campers use trash compactor bags as liners.

I'd get one that is inherently watertight and doesn't need a cover. The covet is extra weight and space. Or you forget to bring it. Or you have to stop mid-ride to put it on.

I don't know the model, but people I see commuting use what are roll up drybag packs. I have a drybag backpack for kayaking I will try once rain season starts. Only downside it doesn't have the fancy anti sweat mesh panel. But if it rains, it's wet anyway.

This has been a little harder than I thought - there are a lot of options out there, but most are too small, or aren't really for full bike commuters, more for people packing just laptops and files and maybe a shirt or something.
That Osprey pack is still the tops because it has a lot of storage sorting options - especually since I will be bringing dress shoes back and forth sometimes, as well as having to pack shower sandals, and soaps/creams, etc every day. Most other packs are just giant single caverns, or they're just too small.

The closest competitor is the Chrome Industries Barrage - but again, it's got a slot for a laptop but the rest is just one big hole. I'd rather separate my things into existing different built in pouches, then buy a whole mess of separate carrying cases for stuff.

If you don't have a locker, you can store soap, gel, dress shoes etc. In your desk maybe? That way you don't have yo schlepp it every day.
I keep my work shoes, shampoo etc under or in my desk for that reason. I only bring new towel, and clothes for after shower with me every day.

Maybe that helps you?

It may not be possible for you, but maybe instead of schlepping a laptop forth and back, get a home PC and remote into the work laptop. That may be out of your control....

If you need to haul a lot of stuff, a Timbuk2 messenger bag in large might be good. I alternated between that on large load days and a chrome industries citizen when I didn’t need to lug around so much stuff.
I prefer the older timbuk2 stuff over their newer bags, though.

the shower/day use locker is across the street at the YMCA, so keeping stuff at my desk is pretty much a non-starter. I will eventually have a pair of dress shoes there, but that’s about the most I can do.
My office also has a “we want you in the office” policy so working from home isn’t prevalent. I won’t need to bring the laptop home everyday but I need the ability as I don’t know what days I will need to.

So there is a work place worse than mine....

With all the stuff you need to carry, a backpack will be heavy and bounce around. I'd look into panniers. I only carry my clothes, food and towel on my back and that is about the limit. Some people at my work have panniers they can take off and carry in like a bag.

If you already have another large bagpack, you could try how the weight feels. A modern, better backpack will make things somewhat easier, but you still will have a lot of weight high up.

All depends on the distance you ride. I decided on a bagpack since i rather suffer with that, than suffering adding a rack etc. but my commute is 9 km only. if it was longer, or i had more weight to carry, panniers would be more appealing.

The problem with carrying a backpack is that it necessitates carrying more stuff like a change of shirts because of the extra sweat, etc. That said, I love my Osprey bag because of the support mesh that helps keep the back cool. During graduate school, I commuted every day to school and to hospital internships, so I couldn't show up sweaty. I had a small cabinet under the desk where I could keep my backpack, helmet and shoes, so it worked out fine. I'm in the process of moving to my next clinical job which will be about 8 miles farther away and I'm not going to be wearing clipless shoes, so I have to be looking at other options. Anyway, I digress. The messenger bag thing might be cool, but it's for folks who need quick access to their cargo. You probably don't want all that weight on just one shoulder and a little support from a dogleg strap; that said, my Crumpler messenger bag got me completely through undergrad and years of bicycle wrenching, and it still is in fantastic condition, albeit a bit dirty. If you must go with a pack to be worn on your body, get one that has good breathing room on your back and can accommodate hip support. Good warranty and customer service are pluses.

Well, I ordered the Osprey Radial backapck I linked to in the 2nd post. I'm not worried about carrying extra clothes because I ride in bike shorts/shirt, and pack my work clothes. It's a 9.5 mile route. It sounds like a lot, but it's not too bad - just more than I used to have to take. I already have an Osprey day-hiking pack (forget the name) from around 2016 - I used that for the commuting for about 3 years before WFH started at the beginning of covid. That was my old job and I had a permanent locker in the gym where I kept about 5 hangers for hanging up my bike stuff to dry, a belt, a pair of shoes, and facial cream, etc. The showers had shampoo and body wash pumps, and towels were plentiful and provided so I never needed any of that stuff. All I carried was my work clothes, and a different pair of shoes now and then - and sometimes an extra layer for changing commute temps.

But now, the Y doesn't provide anything but a temp locker so I have to carry towel, soap, shower flip flops, work clothes, laptop with me every day. I can hang the bike clothes in the locker during the day along with the towel (it's a microfiber packing hiking towel) and the flip flops. I'll bring my pack with helmet, over to the office and put it under my desk.

I didn't want to use a rack & panniers because i use my commuter bike for other things (weekly rides) and I didn't want a rack hanging around on it. Plus, the panniers I have aren't big enough for a laptop and I'd rather have a laptop backpack I can double use for traveling.

Hopefully it'll work out!

Little late to the party, but I recommend timbuk2 messenger bags. Simple, bomber. Been using them for 20+ years. Currently using the second one I’ve ever purchased. Size medium. Fits a surprising amount of stuff!

I'm not here to second-guess your preferences or tell you what to do, but I'm genuinely curious: why do you prefer a backpack over a pannier?

If you want a backpack for ease of walking across the street to the YMCA but you already have a rack, maybe something like the Ortlieb Vario would be a good fit?

The rack isn't currently on the bike. It partly because it's not just my dedicated commuter bike. It's a single speed I use for group rides and general buffoonery. So I didn't want a rack hanging off the back of it. I've never thought the convertible pannier-to-backpacks worked great - espeically hacing the shoulder straps to contend with while putting on the rack, etc. I rode with a rack and pannier for about 3 years. For me, I just enjoy the back pack more.

The Osprey Radial pack arrived. It's nice. It's got a crapton of room and I love all the pocket/pouches options. Plus like most Osprey packs it's got the back vent thing so that's a plus.In fact it's orobably more room than I'll usually need because I won't always have to bring dress shoes - I'll leave a pair under my desk. Looking forward to using it this coming week!

I really liked a few of the Chrome Industries backpacks but they were mostly just one big deep cavernous void. I needed to separate things.