I like rack trunks. But if you're commuting, you have a lot of things to carry, like lunch, change of clothes, rain gear etc.

I couldn't find a trunk that's 20l in volume and backpacks or duffels strapped to the rack are too cumbersome.

I now use an Arkel pannier/backpack. The advantage is that when I over stuff it and hang it off the left side, it looks bulky so motorists tend to give me more clearance. At least that's what I like to think.

If I carried a laptop every day, I'd want stable, strapped-down panniers for it. Other than that, I don't really like them for commuting. I just strap my backpack on the rear rack, and do something else on the bike that doesn't have one.

I *hate* riding with a backpack on. It's uncomfortable. And it can obstruct your view when you turn your head to look over your shoulder, which is necessary to ride safely in traffic.

On the other hand, panniers are attached to the bike when you ride. You're not carrying any weight on your shoulders or torso. You're not going to get a sweaty back. Mobility and sight are unimpeded. When you get off the bike, just take the pannier with you.

There are even panniers that can be worn as backpacks, making them even more convenient off the bike. Banjo Brothers and Blackburn offer some reasonably priced models (below). Arkel and Ortlieb offer some higher-end versions.

Banjo Brothers Convertible Backpack Pannier
Blackburn Wayside Backpack & Pannier

You must have a huge non-contoured backpack to impede view.

Also, those Ortlieb panniers are excellent as a pannier and ****ty as a backpack (no comfort). I'll admit that they're extremely durable (usually about 10 years of usage before wearing through) but like most things German, lacking in comfort.

It's not the slimmest backpack ever, so that's definitely a factor, but it's also a matter of posture. The more upright you are, the less likely it is to be a problem.

I have an Arc'tetyx Spear 20 and it's never been a problem in an urban non-race environment. Not even in the drops.

Good info for the OP. I personally hate riding with a backpack, but it might be a good solution for him. Different strokes and all that.

I just fought through that madhouse this Oxford circus my up yo Newmarket for a horserace. Needed my black tie suit in one hand and would've hated a messenger bag or anything else.

Long live the arc'teryx spear 20!!!!!!!!

I think it must depend on your frame as well. I never feel my pannier on on my long, touring frame, whereas I do feel a pull when I'm wearing a heavily loaded backpack up high. As far as expense, Axiom makes a very cheap transit-oriented series I like called the "Mount Royal." You can get it for $25. Two sided, saddle-bags style.

Regarding all these Londoners with backpacks, it couldn't be any different in NYC. A good bit of totes and messenger bags on the train here. It's absolutely annoying when passengers get on with backpacks and leave them on, taking up twice the space on crowded trains. They have messages over the intercom that tell you to hold it at your feet. The worst: since your backpack lacks nerve-endings, you don't feel when it's prodding others. Ugh, sorry for the tangent here...

Packs always come off on the tube, we're quite considerate. Never really liked NYC (Bronx is OK tho.)

backpack by a mile. my backpack is like a loyal buddy. baskets are real handy too if you don't want a bag on your back.

I hate backpack. My back gets way too much sweaty. Here's my bike configured in commute mode. That bag has expandable side pannier if you need more room and expandable top lid for even more room. Clips to the rack in seconds. It's also water resistant but they do also have a rain cover for those downpour. Comes with a shoulder strap so backpack looses that advantage when carrying it away from the bike.

Did a 35 mi ride with my Osprey Radial 26 pack today. Brought it for a change of clothes because of iffy weather. Didn't really notice it. It has a mesh back with and air space that allows air to flow between the back and pack and it works.

I highly recommend this pack. If you do this a lot I would look for a bike-specific pack like this one. It has lots of great features that makes it a pleasure to use. like a "kick stand" so you can sit the pack upright - it basically is a stiff underside that parks the pack upright and is very stable, so you can get things in an out with ease. A pull out rain cobver, soft poacket for phone, a bottle holder, helmet holder etc, etc.

I rode with a backpack for a while when I first started commuting. I used the same Osprey Radial as GeneO above, but in the 34 liter size. I loved that pack for commuting. It was bright, came with a raincover, and because of the mesh back panel and rigid frame it was very comfortable. I would recommend it to anyone looking for a good commuting backpack.

Then one day I got hit by a car on campus. After I recovered I quickly found out that my back couldn't handle the weight anymore, and I started looking for pannier options. I first tried the Banjo Brothers Backpack/Pannier. It was good for the cost, but the little hook that it attaches to at the base of the rack wore a hole in mine after about a year of use. Now I'm using the Arkel Bug Backpack/Pannier, and for the added cost it is a MUCH better bag. It has better organization, better water bottle pockets, and a helmet holding pocket for off the bike use.

So those are my recommendations for each style.

If you carry heavy stuff, or have an aversion to back sweat, go the pannier route.

Personally though, I'm not a pannier fan. Panniers make my bike feel heavy and less agile, so I use a backpack for my 15 miles of bike commuting. I'm a sweaty mess when I get to work, no matter what, so back sweat is no issue at all. And I try to keep my load at a reasonably sensible weight.

I initially tried brands like Osprey and Ortlieb, but my personal choice of backpack is a Chrome Barrage. I've been using it since they first came out, maybe 4 years ago? It's pretty much totally weatherproof, and ballistic as all getup. The cargo net on the back is great for storing my helmet, or other large objects when shopping.

I initially was all about carrying everything on the bike so I rode unencumbered. Long story made short - now I ride with a Patagonia Atom sling bag (with stabilizer strap) and the only thing on the bike is my computer. Phone/headphones are bluetooth so that's in the bag pocket on the strap. Water bottles and everything else in the bag. Mini u lock on the outside of the bag. Keys on the internal lanyard. Lights attached to the bag. Now when I stop, I just lock and leave instead of standing there stripping the bike to prevent theft.
I still have the front rack on my bike for when I go grocery shopping for big loads and use my cooler/panniers. but day to day it's the sling bag with a foldup nylon backpack inside for unexpected purchases. The backpack goes on my back and the sling bag rides as a front bag at my waist. The sling leaves plenty of circulation around my back, too.

As a third option... I prefer a side basket. It's just so easy to toss stuff into it, and it's also where I store my helmet and other gear. Kind of an odd side effect is that the basket is on the drive side, so it functions as a sort of roll cage for the delicate bits of the drivetrain, protecting the latter when I park the bike in some crowded place.

It's a Wald 585, attached with hose clamps, has lasted for 20 years so far. Wald is one of those amazing historical brands that just keeps going, making good honest stuff.

Again, I'm using the backpack off the bike. I'm flying over to Salt Lake City for a conference and a few days of camping. The backpack makes an excellent daypack, while the 65l back is hood for the bulk of the gear.

Try that with a pannier/backpack combo bag

Upgrade your bike before visit mountains because if there is any issue no one will help

Wald folding baskets on the rear rack. Just drop the backpack in and go (through a bungee cargo net over the top if you're worried about bumps). Gives you the ease of walking around with a backpack without the sweaty back or weight. Switch modes in seconds. When I bought them, a pair was in the $30 range and I already had the backpack that fit in it. Also made grocery trips a lot easier.

A backpack will work you do not need panniers to start just to see if you like bike commuting.

No bikes this trip. Marley is staying in UK and it's only hiking.

Clearly, it's a matter of taste. I never really liked riding with a backpack, but since so many people here endorse them, and since there are these new, narrow backpacks, I decided to try one, and it works well for me. It depends on the bike I'm riding. I don't like to attach things to my racing bike which make it heavy, so I use a backpack when I ride it. The trick is to use a small backpack so I don't put too much stuff in it. I rarely carry more than my laptop, lunch, and a couple of garments.

I rode with a backpack for years and never liked it much. It worked well enough, but for me, it caused discomfort in my chicken wings and a wet, nasty back from sweat.

Now that I am older, self-employed, and maintaining deteriorating knees, my days of aggressive riding and bunny-hopping are behind me. I can relax and choose a route and a pace that works for me. Rack and panniers are a much better choice.

I also use my bike for shopping and many other hauling activities, so again, the panniers make more sense for this stage of my cycling journey.

All that being said, backpacks are an excellent option if they work for your needs / system.

It all comes down to the level of temperature/back sweat you can live with!