I just bought my GF an Arc'teryx Spear 20 today (and saw my first Surly in Germany at the outdoor store as well). It fit her quite well and we didn't even realize that it had the capacity for carry a water bag, so that's a nice bonus.

We'll try it on commuting trip and day rides and let you know how it goes.

Here it is:

nice bag, but I don't like wearing a backpack while riding.

sorry man. it must limit your options

Topeak MTX. Backpacks suck on bikes.

your opinion.

if you ride on flat ground, in the middle of a desert, maybe it doesn't matter.

but if you're on/off the bike all the time, it's quite nice. in addition, the bag doesn't have a built in holster, which may be a limitation for people in the US.\

also, only with someone of limited knowledge would call a 20L rucksack a "backpack"

a 20 litre pack, worn on the back, is indeed a back pack in US english, whatever you might call it. Please control the hate.

Meh. I'm in the backpacking set, but I'm not too impressed with this particular one. Sure, it has a couple of good features going for it, but lacks a rain cover of it's own and has virtually no organizational capacity that I could tell from doing a Google search. Besides, 20L/1,200 c.i. capacity is a bit too small for my needs.

I'm not in the backpacking set, but I realize it does work for some types of commuting... especially shorter commutes, temps not too hot. Backpacks are also great in that there's lots of them around, easy to get second hand.

to be honest, it really complements our current bags (2 messenger bags ... 1 with organizational capacity via a laptop separator and one without any organization, and one 65L Apline Lowe for longer trips).

the commute isn't super long and the bag easily handles 2 changes of clothes and lunch for day without being super huge.

also, it may not be waterproof, but i have a hard time imagining anything getting really wet inside (doesn't rain so long/heavy here)

i'll take a ride with it today and see how it goes.

Looks like a nice bag. Arc Teryx stuff is rock solid, build-wise. Let us know how it works once you give it a spin. I'm in the backpacking camp & agree that they are more practical than panniers (for me & my uses).

I just did a 50-mile ride with it and loved it. it's really small and sits high on my back. i also has a strap that goes around my lower rib cage. i'd highly recommend trying one on.

Even the opening at the top is brilliant.