The ideal lightweight rucksack?

I've been having a long discussion this weekend, (as you do) about what would go to make up the most useful, generally practical, reasonably sized, functional, lightweight rucksack.

What should it include, and what should it leave out? The average user I have in mind, is the day/weekend hiker anywhere from 'urban outdoors' (that's the cool new word for people on the High St who wear outdoor gear) to hill walking/backpacking, with a bias towards all things lightweight.

NOT uberlightweight - more general lightweight so 5-10kg use rather than 12kg+.

I would be interested to see what folks here think ...

So;

Approx 40-45lt capacity, roll top enclosure but with a removeable pouch which clips into the neck inside which can hold small valuables, or a 1 lt Platy.

Side and bottom compression. Deep side mesh pockets with a sloped entrance eitherside, and a second deeper mesh pocket the full height of the bag.

Front pocket - my preference is for a large mesh pocket with the ability to clip it closed at the neck, so that when you open the top part of the sack it doesn't fally open.

Set back lengths, with a shoulder harness for male and female form to suit.

Simple shoulder harness, with a few webbing loops to attach items should you want. A hipbelt which clips in (but as the pack is carrying a light load the idea is not to have one) but if the hipbelt is there, maybe a couple of mesh pockets.

NO hydration slot down the back, but a wide pouch so you could use your sleeping pad as a back support. But supplied without any padding or support.

Does it really need any mesh on the back panel I wonder? Most of my basic bags done have any and I don't really notice any performance (sweat) issues?

Material? Hmm ripstop Nylon maybe for part of it, but possibly something a bit more durable like thin Cordura, Kevlar or Dyneema for the main ebrasive areas.

Keep in mind the KISS principle, but what do folks think of this I wonder?

Awfully close to a lot of MMarathon style sacs there

I'd certainly want a hip belt for the pockets. And do like being able to loosen off the shoulder straps if need be. Gets you some good venting actually. 

Not urban outdoors though as that 'needs' rather tougher fabrics than lightweight backpacking. The stuff will get much more abuse over time.

As an aside, have you considered front pouches (removable like the OMM TRio)? If you are looking at a sack like this would combining it with a front pouch help the balance and functionality a bit?

I had a  thought, which might not work, but has anyone used their tent flysheet or a tarp as a back padding? I have a 20litre alpkit drybag sack which has an externally reached pocket at the back. This contains a removeable sitmat pad and can take a bladder. It made me think for comfort a tarp could go in there. Probably a non-idea.

My experience of mesh pockets are they can be prone to fraying a lot easier than the sacks. However they are useful.

Would be interested in your design when you put it out there Bob. THink you have all the main bits down well. I reckon you'll come up with some interesting extra features too. I'd always look to other makes. I mean OMM have some good features. THe hipbelt pockets, removeable (without permanent damage) of bits like the compression panel. The UGR too. Others too do some designs with unique features. Without copying you could design better versions from a few makers. AS a punter I have often seen sacks and wished a combination of features from different makes and models would best suit me.

a removeable frame sheet so you have the option of fulll on outdoors use or for use anywhere e.g. without a framesheet you need a sleep roll inside the pack to provide structure and to stop things poking you in the back. this then becomes "non-lightweight" when the pack is used for anything else.

easy access side pcokets with compression straps passing on the inside of the pockets

large hipbelt pocktes but i've found placement and size crucial to avoid your inner arm brushing against them.

elastic material rather than mesh for a front pocket - mesh snags on things and it's easier to damage wha's inside. makes what you're carrying invisible too (think urban)

The average user I have in mind, is the day/weekend hiker

That's a rather schizophrenic "average".  An average day hike doesn't need nearly as much space as an average weekend one.  And also the amount of space one needs varies with time, so I'll cart about far more in midwinter than midsummer if all else is equal.

The variation is also why I have multiple packs.  Because a single one would not be ideal in every situation.

Set back lengths, with a shoulder harness for male and female form to suit.

Adjustables don't make much sense on a lightweight so I'm with you there.  The second bit though needs to acknowledge that a notional female may differ from another notional female at least as much as she differs from a notional man.  In theory you want a range of back sizes and shapes that would fit anyone, but in practice that's just not possible and you'll have to rule out some folk.

Pete.

I've already got my "perfect" lightweight sack, if you can call 715gr lightweight, the Vaude Triset ultralight, it's everything i want from a pack, light, relatively tough, the back system is spot on and it's very comfortable even with 10kg in it.

35lt though, not 40, but big enough for me, and it's without doubt my favourite piece of kit.

Btw, i can't stand frameless packs and would never buy another one.

Include a little history in your walks. Pecsaetan - Ancient Derbyshire, Staffordshire and South Yorkshire - http://pecsaetan.weebly.com/

Add another requirement - capable of meeting cabin baggage size limits on most airlines.

John Kilgour wrote (see)

Add another requirement - capable of meeting cabin baggage size limits on most airlines.

I bought a 40L sack, Golite Peak, having used a 70L sack for 30 years which was getting less-full as my gear shrunk. I tried to put my camping gear with autumnal clothing in 40L and it was an extremely tight sack to point of unusable on-the-hill. I concluded 50L requirement when camping.

When not camping, 25L would do even in winter.

I fly many times with a backpack. My experience:

• sod the baggage rules, they are not enforced by the check-in, gate or cabin crews, it is truly first-come-first-served basis so unless you board first such to the back of the plane or have some kind of privilaged status, you can often find no room in overhead bins for the "allowed" cabin bag size.
• under-seat is random space, some seats have a metal box taking half your feet space.
• Do not over-use compression bags as it makes the bag less able to squish to available space, or place compression bags inside a daysack. 
• Take a simple daysack inside the backpack. If the backpack won't fit overhead, remove the daysack and place under-seat and then the backpack might fit overhead or at least the backpack is checked minus the more precious items you keep in the daysack.
• Simple and/or removable straps and buckles help the bag survive.Assume anything poking out will be torn off or lost.

Bob C - backpackinglight.co.uk wrote (see)

What about attachment points? Do we really need any at all? The walking/tent poles could slide down the side pockets, so what's the others for?

I'd say yes to attachment points for poles or axes. Yes, you can slide these into the side pockets but that then potentially limits what else you can put in there and how easily you can access it (thinking esp. map and water bottle - two things which many folk want easy on-the-go access to). Also, when carried in side pockets, poles and esp. a long ice axe, can sit uncomfortably high and feel rather near your head, so 'standard' pole/axe fitments prevent that .

For the sake of effectively 4 pieces of light bungee/webbing and cordlocks I'd rather see them present - they could even be removeable for those who can live without them.

I can see your point Matt, but what would be the ideal connection points and where for Ice Axes?

I think poles would be placed pretty well anywhere, but as I'm not a Axe user (man!) is it better for the head to be high or low in the pack? Most attchements points I've seen seem to have the head of the pole low central on the pack, rather than high central, if you get my drift?

Beaker wrote (see)

"Does it really need any mesh on the back panel I wonder? Most of my basic bags done have any and I don't really notice any performance (sweat) issues?" Yes please. I'm a bit overweight and not as fit as I could be and so prone to a bit of sweating. Anything to ventilate my back is welcome.

Sorry but that made me LoL. There is no relationship between weight, fitness, and sweating. All that being fitter and less weight does is make you move faster. Obviously walking in a group, if you're fit/unfit relative than the group you'll sweat less/more when keeping at the group's pace.

My first packs were flush on the back and I soaked the backpack, I must have weighed like 10St but still sweating. I got a later pack type which those arches but still sweated at shoulders/hips, and the arch reduced the pack's volume. The ones with a deep meshed back seem good compromise of not intruding into the pack's volume, of which the only I have experience with is the GoLite peak and it seems a good approach.

On the issue of loops for axes, etc - one of my cheapest packs has a small stiched loop on the sack and through it you loop an elasticated loop large enough to hold an axe and these elasticated loops can be removed. Ideal compromise???

I reckon attachments for axes or poles can easily be the same thing anyway. My preference is for two sets, mounted at either side of the rear panel. Elastic bungy with a cordlock serves for both upper and lower fastenings. I'd carry an axe with the head at the base of the pack and the spike upwards (but I use pretty short axes so no real risk of having someone's eye out!). Poles tend to go together as a pair with the handles up and tips down. In winter I'd probably have both - hence 2 sets of fittings are useful.

Nigel's notion of small loops that permit the addition of bungee (or other straps) as required, is a good one.