We are often asked if we can make lightweight rucksacks and the answer is yes we can and do. Quite often when we have discussed with the customer what exactly they are after they end up with one of our standard rucksacks because they are not that heavy to begin with. In our opinion, the easiest way to lower the weight of a rucksack is to remove all the features that can be done without. Take this to the extreme and we have a potato sack with shoulder straps. By reducing all features to an absolute minimum, we can end up with a light rucksack but one that is not very functional in use. It’s all about compromise.
Most people who talk to us about lightweight rucksacks believe that if you use lighter weight fabric you will end up with a lightweight sack. Whilst this does have an effect on weight it is not as great as most people imagine. After all, we do have to make it out of some fabric so that the weight is only reducing not disappearing! If you remove features, however, you are removing all of their weight so generally this has a far more significant effect.
At Aiguille we believe that on the sacks that we build we have got the balance between function and weight right for the vast majority of end users. We also believe that everyone is an individual and we are happy to produce bespoke rucksacks for our customers, for example, if you never use ice axe loops but use the compression straps for your axes instead we will miss the ice axe loops off or if you do not need wand pockets or an extendable lid, we will miss them off. All this saves weight. On the other hand if you would like an under lid pocket as well as a box lid pocket, no problem, but it does add weight.
Back to fabrics and trade off. We have mentioned in our advice on Climbing/Alpine rucksacks that we feel that 1-1.5kg is an acceptable weight for this end use and the reasons why. By using 1000D texturised nylon for the main body of the sack we can easily achieve this for a well-featured Climbing/Alpine rucksack and therefore fullfil our criteria for being ‘bomb-proof’ and reasonably lightweight. I am talking about the vast majority of end users here, that is, people who are using one rucksack as a summer crag sack, a Scottish winter rucksack and for their summer trip to the Alps or Dollies.
If we move beyond this to people who want to get the weight down further and are willing to sacrifice the longevity of their sack, this weight can be reduced to around 900gm or 700gm stripped weight for a 35L Alpine rucksack that is still total practical in use. However, do not expect to see many seasons using this as a summer crag sack on grit stone. To take things a stage on from here we can, as mentioned elsewhere, easily get a 45L sack to below 500gm but at this stage we are normally talking to people who require lightweight for a particular project and are willing to accept the limitations. See quote below from Climbing/Alpine Rucksacks on an alternative to lightweight fabric.
`Empty your mates sack that they reckon they have pared the gear down to a minimum. Weigh what you think they can leave out. Let them do the same to yours. The resulting ‘discussion’ should keep you entertained for years. Get the point? We can always reduce weight so why compromise the durability of the item which has to carry it all? If you rip the side out of a lightweight sack on a haul or chimney high on a route, life can get pretty interesting if not downright dangerous if all your kit is spread out several hundred metres below on the glacier.`
This same criteria has and can be applied to trekking rucksacks. Take our 65L Verte rucksack as an example. In 1000D texturised nylon this weighs in at 2.13kg. By using a 420D packcloth nylon we could reduce the weight by 170gm, not very much really. In fact the total weight of 1000D fabric is only 470 gm or 22% of the sack. Even at its original weight of 2.13kg for a load carrying sack of this size this is pretty light in comparison to many sacks of this volume especially considering the fabric used.
The problem here is people will often use the sack to travel to their destination, for example, fly London to Marrakesh and then bus or taxi to Imlil before their trek in the Atlas. Most damage that we see is caused by this aspect of the trip, on airport conveyor belts and roof racks of cars or buses. It is often totally impractical to put the sack in a travel tote to protect it during transport as there will be nowhere to leave this and you would not want to carry it on the trek (more weight!). So although on the trek a lightweight rucksack would fullfil all our needs, the travel aspect will not necessarily let us use one if we want the sack to last more than a couple of trips.
Back to features, by which I mean zips, webbing and buckles. On the Verte there is 17.25m of 25mm webbing alone, here we do have scope for making considerable weight saving but this may be at the expense of some practicality. UV exposure will weaken a sack over time and this has a greater effect on lighter weight fabrics. Unlike tents, sleeping bags, down jackets, etc., your rucksack is always exposed to UV light whenever you are in the outdoors reducing the life of the rucksack although this obviously has a lesser effect in the UK than it does in the Alps or Himalayas. We need to be realistic about the life of a lightweight rucksack and this is why we would hesitate to recommend them for the average end user.
Lastly, also consider the fact that carrying a load in a rucksack that has had all of its load control features stripped off and is using thinner foams on the load bearing areas can cost you more in energy than you are saving from weight reduction.