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Gear review: Rucksacks for wild camping

Gear review: Rucksacks for wild camping


Postby Paul Webster » Thu Feb 28, 2013 6:18 pm

Phil Turner wrote:Rucksacks are load carriers, so must be selected based on the weight and volume of said load. Lightweight loads can be accommodated in a simple frameless rucksack – perhaps with a stiffened backpad and simple hipbelt – but once weight reaches about 10kg some kind of frame will be appreciated.....


Read Phil's full review of rucksacks for wildcamping - and let us know what you use 8)
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Re: Gear review: Rucksacks for wild camping

Postby rockhopper » Thu Feb 28, 2013 7:27 pm

Good to see your conclusion on the Exos 58. Following several recommendations I recently bought an Exos 58 to replace my Berghaus C71. I did like the C71 and its bioflex system but the rucksack alone was about 2.6kg, ie nearly 1.5kg heavier than the Exos 58. I also tried an Osprey Kestrel 68 (as I use a Kestrel 38 as a daypack) but rather oddly found that I could get my stuff more easily into the Exos 58 despite it being slightly smaller. I've yet to use the Exos 58 but have some plans for the coming months - cheers :)
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Re: Gear review: Rucksacks for wild camping

Postby Rudolph » Thu Feb 28, 2013 7:51 pm

This frame should transfer the weight of the load from the weak muscles in the shoulders to the waist to take advantage of those large leg muscles which are also closer to an adult’s centre of gravity


Eh? :? :? :?

Still, glad to see the response to the Exos 58. I reckon the 58 is too big for 3 season use and wonder why the Exos 46 which is cheaper and a little lighter was not included chosen.
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Re: Gear review: Rucksacks for wild camping

Postby PhilTurner » Thu Feb 28, 2013 9:02 pm

Rudolph wrote:
This frame should transfer the weight of the load from the weak muscles in the shoulders to the waist to take advantage of those large leg muscles which are also closer to an adult’s centre of gravity


Eh? :? :? :?


Hi Rudolph - which bit confuses you?
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Re: Gear review: Rucksacks for wild camping

Postby Rudolph » Thu Feb 28, 2013 11:24 pm

Why is transferring the load to a point closer to the adult's centre of gravity relevant. Changing the load point does not alter the centre of gravity of the combined person / rucksack nor the centre of gravity of the pack. There may well be something about getting better load stability with a framed rucksack because of the improved binding of sack to person but that was not what was said.

Also, the leg muscles surely take the same force wherever the load is taken (unless you strap it to your foot). The point of taking the force on the waist is that it doesn't load the torso.

I'm confused about both these points as I must be missing something.
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Re: Gear review: Rucksacks for wild camping

Postby nathan79 » Fri Mar 01, 2013 1:02 am

I checked out the Exos 48, nice pack but shame about the slim straps and tiny buckles. Great, uber-light pack if they don't bother you.

I picked up a 65L Mammut pack last year, The Heron Element, for £60 quid and that's been my pack of choice. 1.7Kg, wads of room and a comfy carry.
This one should do me for years, but I'm intrigued by Montane's new 55L Grand Tour should I ever need a replacement.
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Re: Gear review: Rucksacks for wild camping

Postby Klaasloopt » Fri Mar 01, 2013 4:44 pm

Rudolph wrote: I reckon the 58 is too big for 3 season use and wonder why the Exos 46 which is cheaper and a little lighter was not included chosen.


I agree. I own a '46', an L version, which is about 50 litres an comfortable for loads up to 14kg. (my early spring gear in it weighs 8,8 kg excluding food and fuel). I think the '58' is best chosen if tent and sleeping bag are not-so-lightweight or voluminous. The L version of the 46 weighs 1.020 grammes.
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Re: Gear review: Rucksacks for wild camping

Postby tenohfive » Fri Mar 01, 2013 6:33 pm

Rudolph wrote:Why is transferring the load to a point closer to the adult's centre of gravity relevant. Changing the load point does not alter the centre of gravity of the combined person / rucksack nor the centre of gravity of the pack.


The lower the point of weight transference the lower the centre of gravity for the loaded person overall surely? That to me would be a good thing?
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Re: Gear review: Rucksacks for wild camping

Postby Rudolph » Fri Mar 01, 2013 11:22 pm

tenohfive wrote:The lower the point of weight transference the lower the centre of gravity for the loaded person overall surely?


I think that's what the reviewer thought. But it's wrong. Centre of gravity is determined only by the distribution of mass within a system. That's not affected by the points of contact betwen the different parts of the system.

I really don't understand the explanation the reviewer gave for the genuine advantages of a frame system. Maybe there is some literature out there which has this same explanation in it?
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Re: Gear review: Rucksacks for wild camping

Postby Paul Webster » Sat Mar 02, 2013 9:36 am

The point about centre of gravity may be correct if the person and the pack are completely stationary, but when you are walking along the pack (and weight inside it) has its own momentum, as does the walker's body. I've no expertise on this, but surely the advantage of the weight being lower is that your leg muscles are better placed to resist this momentum? If the objective is to remain stable i.e. not to fall if you stumble, kick a rock etc., then the fulcrum point could be thought of as your feet, and if the load is lower on your body then wouldn't less force from your muscles would be required to stay upright than if the load was further from your feet? I think it is remaining stable whilst walking along with the pack and changing direction etc. - managing the momentum of the weight - which demands the most effort from your muscles rather than simply holding the weight up. So a would a pack which has the weight lower will require less effort to walk stably in in a real life outdoors situation on rougher ground? This would help explain why the African way of carrying things balanced on your height needs the expert skill of keeping their body completely straight, upright and perfectly steady whilst walking in order to work well.

That said, I have personally used unframed packs for some years - and don't even usually have a hipbelt, which some people think is crazy. I use the most minimalist GoLite packs - the no-longer-available Ray Jardine designed Breeze and Gust - but with these the shaping of the pack itself is what transfers the weight onto your bum instead of all being on your shoulders. I think the Jam is the closest modern equivalent, though it is heavier.

Many of the rucksacks are available in different capacities, but the review tries to compare those with roughly the same capacity for a fair comparison - manufacturers were asked to submit 60l sacks for this review. Different people may prefer a larger or smaller pack - depending on what sort of trips / length of trips are planned.
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Re: Gear review: Rucksacks for wild camping

Postby Rudolph » Sat Mar 02, 2013 11:10 am

The weight is not lower!!!!! The point of the centre of gravity (or centre of mass if we are talking about accelerations caused by walking) being independent of the points of contact is true for all circumstances. Of course balancing somthing on your head is difficult. That's because 1). the centre of mass of the object is above the centre of effort which is a inherently unstable 2) the combined centre of mass of person and object is higher becuase the load is higher. 3) the head is not generally flat on top so it's hard to keep the object from wobbling.

Back to the case of a rucksack.The belt/hips take most of the downward force for a framed rucksack. But the sideways forces caused by the mass being accelerated and deccelerated by all the wobbles, stops and starts of walking has to be corrected by the point of contact higher up as well as the belt. The balance between these two has to act through the centre of mass of the loaded rucksack. The position of the COM is determined solely by the way the rucksack is packed.

These total corrective forces which need to be applied to the load in the rucksac don't change. The moment of the forces about the foot on the ground required to control the rucksack don't change however the pack is strapped to the body. The total upward force has to balance the weight of the rucksack, the total moment applied to the rucksac (taken about the foot or any other point) has to balance the moment of the acceleration of the centre of mass of the rucksack about that same point. You can move the points of contact about and the lateral forces change as a result, but the moment about the foot stays constant. Sorry, but its just basic physics / mechanics.

I believe the framed is generally more stable, but I think it's because the points of contact on the sack are more rigidly held in position so the rucksac is prevented from swinging. That means the centre of gravity of the rucksack stays put relative to your body and so doesn't alter your balance point.

All this is pretty moot really. we all know to pack the rucksack weight low down for stability and higher up for aerobic efficiency. Stop the rucksack swinging too.

Anyway MrsSanta says she loves me very much but it's time to stop being a physics nerd and go out for a walk. She says using kg to measure weight is not a criminal offence and that Sheldon from the big bang theory is not a good role model for a grown up. :( :(
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Re: Gear review: Rucksacks for wild camping

Postby Guinessman » Sat Mar 02, 2013 12:43 pm

Was in Go Outdoors yersterday and looking at Lightwave 60ltr sack and a Montane 55ltr sack. Has any body used these sacks. They seemed a bit femma and i just wondered how they stand up to load carrying and the effects on the hips and back
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Re: Gear review: Rucksacks for wild camping

Postby PhilTurner » Mon Mar 04, 2013 1:09 pm

Thanks for putting the effort into these lengthy replies - all very interesting stuff. Please note that all comments made in the gear review articles are based on empirical research (ie. actually getting out and using the products), and any secondary sources would always be appropriately referenced.

Following this practical approach, the best way to experience the advantage of a framed pack is to actually get a framed pack, stick some heavy stuff in it and put it on without doing up the hipbelt. After a few miles it'll certainly feel like this weight is being carried on your shoulders and will probably feel pretty unpleasant and unstable, even with the hipbelt done up loosely to prevent the load swinging. Then do the hipbelt up tightly and feel the difference. The frame transfers a significant proportion of the weight to that padded hipbelt, to the extent that load lifter straps can be used to lift the shoulder straps completely clear of the shoulder. A perfectly fitted framed pack will permit a finger between strap and shoulder. In fact - you should be able to remove your arms from the shoulder straps without the pack flopping backwards. Centre of gravity, centre of mass - whatever - I find that I'm more stable and sure-footed with a heavy load that feels like it's closer to my personal centre of gravity at the waist rather than pulling back or pushing down on my shoulders. Your mileage may vary, and that's why we have the forum link at the bottom of each review.

I find frameless packs great for lighter loads though - my personal non-winter multi-day rucksack is about 35 litres but my total packweight is often around 5kg. As well as weighing less a frameless pack will also offer greater freedom of movement and by wearing on just one shoulder in a Jardine-esque manner helps to prevent a sweaty back! This does not reflect the approach taken by the majority of outdoor equipment manufacturers (and therefore buyers) who recommend a 55-75 litre rucksack for multi-day wild camping trips in non-winter conditions. Given the size of some synthetic sleeping bags I can see why.
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Re: Gear review: Rucksacks for wild camping

Postby brpro26 » Mon Mar 04, 2013 6:00 pm

I'd like to through into the equation the coefficient of friction on an inclined plane...this will surely change the COG for any given load and will be inversely proportional to the square root of the piece box. :?
Give me a tonner so I can put all my sh*te in it. :lol:
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Re: Gear review: Rucksacks for wild camping

Postby NickScots » Mon Mar 04, 2013 7:20 pm

A lot of those packs would not be big enough to take an overnight camping trip's kit. Maybe better to see a list or pictures of what kit was put in the rucksacs for an overnight trip.

Unless I carry too much !

Weight needs to be sitting on the hips as much as possible. If you put a water bottle, half full in the top of a rucksac it swooshes about. Put it on the bottom of the rucksac and it moves about less. So heaviest weight at the base.

Conclusion - the VANGO should be best buy

.......There’s very little to distinguish this pack from those costing twice as much – all stitching is neat and whilst the fabrics are chunky they should offer excellent durability....

That statement makes me think it's best buy ?
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