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Title says it all. I have a 65L backpack and would like to mount it on bike rack so it's most convenient to ride with and doesn't catch much air friction.

Currently I'm doing this (sorry for the bad photo quality (it was intended to describe something else) but you can basically see it - putting the big backpack across the rack and securing it with two rubber straps):

enter image description here

Problem is that the backpack of course isn't very stable and takes a lot of air friction. I'd like to fix the greatest possible amount of this.

So, the question -- are there any better backpack mounting methods I didn't think of that would allow me to securely attach the backpack preferably in "vertical" or "lenghtwise parallel with the bike direction" position? Or, is there any equipment or special rack that would allow me to do that without some advanced rubber strap magic? :]

Thanks a lot!

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4 Answers 4

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I would suggest splitting the weight in half and putting it low on your bike for stability. Here is my daily commuting configuration (2 matched 6 gallon plastic waste baskets mounted by hose clamps to a standard bike rack.enter image description here) (Your emptied backpack could be rolled up and placed on top if you need it for off-bike use.)

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  • Or you can put your pack across the top of the bins, where it is supported over most of its length. (I would put the weight in the bins though.)
    – Willeke ♦
    Commented May 13, 2015 at 18:14
  • Interesting idea, but it doesn't serve the frontal area question... this would have more than the pack alone. Plus it looks to add weight mostly at or behind the rear wheels.
    – Criggie ♦
    Commented Nov 21, 2015 at 21:30
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This is more of an extended comment.

If you're mounting it on one side, that's likely to be quite a lot of weight off-centre, which will also affect the handling. I'd aim for vertical, but you'll need something solid underneath to support the weight - like 2/3 of another rack inverted and bolted/clamped to your rack.

Alternatively you might get this to work -- it's meant for baby buggies (strollers) and holds the weight quite long way back. It might not be rated for your loads though. The parent category of the linked site might be helpful for inspiration even if you're on the wrong continent.

You'd still need some serious strapping as well as a good way of keeping the rucksack straps out of your wheel (perhaps a rucksack cover on the wrong way round).

I suggest not having the load stick out much behind the back axle -- I've extended my rack backwards to mount panniers with a baby seat, and also used the buggy-mee I linked to above, and I found the centre of gravity so far back made the front wheel grip suffer (partially offset by carrying locks etc on the front forks).

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    One way to manage the straps is to put the backpack on the rack lengthwise and tighten the straps around rack supports. The trick requires unfastening the straps and may not work for tightly padded straps.
    – ojs
    Commented May 1, 2015 at 13:44
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    @ojs that's true for smaller backpacks (I might have a need to try something like this soon) though in some cases unthreading the straps is made to be tricky (stitched after they're threaded). I'm not sure it would work for a full size pack (65L in the Q) which would hang too far back.
    – Chris H
    Commented May 1, 2015 at 15:42
  • Good points. I learned this trick with Finnish Army backpacks which were big but short and wide. 65 L is huge for rack mounting, I would probably use panniers instead or if I really needed the backpack, a trailer.
    – ojs
    Commented May 2, 2015 at 11:29
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    @ojs perhaps the best solution would be to empty the rucksack into front and rear panniers then squash it as much as possible and strap it across the rack.
    – Chris H
    Commented May 2, 2015 at 12:28
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Backpacks are intended and designed for backs. I've biked with a tramping pack on and its not fun (modern ones tend to be too tall behind your head)

I'd go with a trailer. Here's some ideas

These guys make single-wheel trailers and are well known. http://www.bobgear.com/bike-trailers They are "in line" and give the least frontal area increase.

https://www.biketrailershop.com/single-wheel-bike-trailers-e-158.html Some trailers are built with the same size wheel as your bike, so you have a spare with you.

Some more "home made" approaches http://www.cycletrailers.co.nz/html/catalog.html Here's exactly what I meanenter image description here

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There is more than just air friction to consider.

If you extend the rack back then you would have too much weight aft and it would make the font wheel lite (it may even bring it off the ground).

Vertical you don't have base size to secure and now you have weight higher. The bike would be wobbly.

You are not going to have a lot of speed. I would go the current orientation for stability. If you have steel rack you could weld in extensions. You should go steel - a Surly steel rack is like $140.

I would pull some weight like bag / tent and strap it to the handle bar.

Not cheap but a trailer. travoy

Or even more money a cargo bike like a Surly Big Dummy.

.

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    A trailer isn't a bad suggestions. There are more expensive options as well.
    – Kibbee
    Commented May 1, 2015 at 14:26
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    With an alloy rack you could clamp something on, perhaps using p-clips (engineering supply ones rather than the ones designed for seat stays - this is how I extended my rack backwards with aluminium tube). I've sketched out a few folding designs in the past but never got round to prototyping anything.
    – Chris H
    Commented May 1, 2015 at 15:47
  • @ChrisH I don't think an alloy rack with a clamp on will hold a loaded 65L pack. By weld I mean include an angle support piece.
    – paparazzo
    Commented May 1, 2015 at 15:51
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    I was assuming a brace as well for that much load - worst case you could use something like square section extrusion though by the time you'd bought the fittings a trailer would be cheaper. I'm only assuming about 20kg for the pack though (that's what mine used to weigh excluding water when I hiked with a full pack), and it does just work on the existing rack.
    – Chris H
    Commented May 1, 2015 at 15:59
  • well, I'm not going for speed, but if you catch some bad wind with this, you'll suffer. :D Anyway, the backpack isn't that heavy (~13kg at most) and well I was planning some construction anyway -- thanks for mentioning P-clips. :D
    – exa
    Commented May 2, 2015 at 12:01

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