What is a good way to mount / secure a regular backpack, while commuting?

Question

This is a purely commuting issue.

I have an around 3km route to the office, and a regular backpack (laptop, accessories, notebooks, ...) which is not a problem to carry around during autumn and winter months, but in the summer the back of my shirt quickly becomes sweaty from carrying it, and carrying it only on one shoulder isn't so good stability wise, while on the road.

I'm looking for advice, what would be a good way to mount it to a bike, or securing it in some way so it lasts throughout the trip, so I don't have to carry it on me.

I've tried securing it to my rear rack with "bungee ropes" (those elastic ropes), but it tends to slip to the side during the ride, and I'm afraid it might fall down.

Bike: Author Reflex SX trekking, with rear rack installed.

Edit (Clarification of what I'm looking for): Solutions for carrying regular rucksacks, like baskets that can be secured to rear rack, or side baskets (I've yet to see examples of those), or some solutions that would enable securing a backpack directly to a rear rack, but in a way that enables me to quickly clamp/unclamp it. I'm also not interested in buying specialized bike backpacks/panniers, but wish to carry my current one.

Answer 1

Option 1

Your bike has a parcel rack on the rear - I'd suggest exploring modifications to that rack to hold your existing backpack more securely.

Bungee cords are good because they have tension, holding the hooks on. And the length will somewhat adjust for bigger or smaller loads.

Downside - they do slip and move under vibration.

Answer - either make or buy a mesh of bungees to hold your existing bag on top of your rack. Something like this:

I'd secure the rear edge and one side to your rack and organise the hooks so they secure to your seatpost, and to the other side of your rack, forming a nice mesh. Each hole should be too small for your bag to slip through even at full stretch.

The shoulder straps on your bag may hang off the side. Just position it so they don't. If the straps hang through the structure of your rack then line the underside of the rack with some firm PVC scrap plastic (also, that's a decent mudguard too. Or you might want to drape the shoulder straps over your seatpost before securing the mesh down.

Perhaps use carabiners instead of bent wire hooks, for added security.

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Option 2

You have a rear rack, but its not good enough. Use the rack to carry a cage like this:

Picture shows two, but you could easily just ahve one rack on whatever side you prefer. The pictured bags aren't required either - they're more for grocery shopping.

Advantage is that it takes a heck of a bump to throw something up and out of the cage. They will also "concertina" when empty and take up much less space. Also good for keeping long skirts out of the rear wheel!

Downsides are added weight and they're not rated for heavy loads.

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Option 3

You have a rear rack, why not add a matching front rack too ?

This shows a front basket on a rigid MTB. These work well and can carry a lot more weight because of the bottom struts. A bike with front suspension can't carry as much cos the struts would change length.

Advantage, your stuff is right there in sight at all times, its not going to jump out of the basket, and also you can access it easier.

Downside, the handling of the bike might change - it depends how close you can get it to your head tube and how long your stem is. Plus the brake cables can sometimes foul the basket.

Answer 2

It looks a bit funny, but I see many cyclist carry their backpack in child seat (when child is not there obviously). As funny as it may appear, it seems to me this is the way backpack is most securely carried (aside from your own back).

Answer 3

Option 1: Cheap rear pannier to hold backpack.

You mention you already have a backpack you like, and a rear rack on the bike.

I know you're trying to avoid buying more gear, but have you considered buying a single large rear pannier that would be big enough to drop your entire current backpack into? Since it's just for a short commute and is just there to hold another bag (your backpack), you don't need anything special and can buy basically the cheapest one you can find. If the rack clips on the bag you buy turn out to be cheap and crappy, poke holes through the pannier and zip tie it to the rack. Bonus, then you don't need to take the pannier off the bike when you get to work, just take your backpack out of it.

I don't know where you're located, but a quick search of Walmart shows basic panniers starting at under $50. I'm sure you can find similar on Amazon, or can get even cheaper if you look at local used ads, especially if you don't mind buying a well-worn (possible some small holes in it) used pannier. Keeping in mind it's just going to be a backpack holder, and the bonus to a worn out crappy looking one is it's less likely to be stolen if you want to just zip tie it to your rack.

Option 2: Milk crate

I've seen lots of people take old plastic milk crates and bolt them to their rear racks. That should be big enough to put a backpack in. It's ugly, but therefore not appealing to thieves.

Option 3: Ride Slower

Also, not to second-guess your summer sweat assessment, but 3km is a pretty short ride. Have you considered just riding very slowly on the hotter days and see if you still have the same problem? If your ride is not to hilly, I think you can do that even on a hot day without getting sweaty. Even if you ride at the glacial pace of 12km/h, you'll still be there in 15 minutes, much faster than walking.

Bad Option: Bungee backpack directly to rack

You mention you already tried this and found it slipped down. Good. IMO, this is dangerous. If the bag slips down far enough, it or its straps can get tangled in your drivetrain causing damage to the drivetrain or sudden loss of control if your rear wheel locks up.

On a bike tour a few years ago a friend's poorly-secured camp towel slipped down off his rear rack onto his chain while he was pedaling along at a nice clip. It got pulled back into his rear derailleur and in about 2 seconds, jammed the derailleur, which flipped up around the casette, into the spokes (breaking several), before basically exploding. Luckily nobody was hurt, but his derailleur and spokes were trashed, making this my go-to anicdote about the havoc soft items can do when they hit the drivetrain.

Answer 4

I suggest a folding rack like this:

Probably not the best quality and intrinsically weak (the bottom must fold as well). However, since you can fold it when not used, you can also attach securely it to your rack, so it does not get stolen that easily.