We check out the pros and cons of ventilated packs and look at the top designs.
With Berghaus launching their new Air Flow Pro
suspended air back packs
for next spring, 2010, we thought it'd be interesting to run a
quick overview of
the different variations on the
air-vent
back system theme and their strengths and weaknesses as
well as the pros and cons of ventilated back systems.
What's Good Generally?
Mesh back panels hold the main body of the pack away from
your back and allow air to pass over it cooling and venting as it goes.
That means a cooler, less sweaty back and a more efficient physiology
in warm conditions as there's more surface area available to lose heat
from.
What's Not So Good?
The air gap means the load is carried further away from
your back, which in turn can mean you can feel the pack levering away
from your back. To accommodate the back system, pack makers end up with
a long, thin, sometimes curved packing space making them deceptively
low in volume and awkward to pack.
Mesh isn't quite as breathable as you might think, a lot of it is still
solid nylon or whatever, so it may not be as cool as you think it
should be. Plus in cold conditions, wind can get at your back making
for a cold, chilled feeling.
Finally, the systems can be weighty thanks to tensioned plates and rods
needed to hold the load away from your back and the mesh.
Overall
To sum up, good in hot conditions but potentially less so
when it's cool and with some inherent weaknesses that need dealing
with, which is what the leading brands have been doing.
Osprey Atmos - Airspeed
The original Atmos was the first ventilated
pack we really got on with. It used mesh tensioned across a flexible
space frame that flexed with your back and shoulder movement and
transferred load brilliantly making for a great carry with no feel of
leverage from the load.
The second generation of the Atmos has a modified Airspeed system with
far less flex in it and a LightWire alloy frame backed up by a tightly
tensioned mesh back panel. The frame extends round the hips for better
load transfer and cross struts across the frame hold things stiffer and
control the flex, which gives a shallower air gap which is better for
stability. There's no internal plate, it relies on tension from the
frame which makes it relatively light.
The sides aren't completely open, but crescent-shaped holes allow
reasonable side ventilation. Carries well, though the hip area can be
problematic if you're shaped wrongly. Venting not quite as good as some.
Lowe Alpine Air Zone
Centro
Lowe Alpine makes some excellent and innovative packs,
interestingly, they developed a meshless system where two blocks held
the pack off the back giving an uninterrupted air gap. Gregory is doing
something similar for 2010.
The company went back to the trampolene model last year though with the
AirZone system. This uses a stiffened plate supported by an internal
alloy frame, which you can't see, but again stiffens the back meaning
Lowe can get away with a smaller air gap thanks to increased stiffness.
The mesh area itself has been minimised with big cut-outs
allowing air to get straight to the back with no mesh in the way.
Finally an adaptive hip-belt caters for variations in hip
shape.
It's a well developed system that carries very well and still gets as
much air to the back as possible. Narrow air gap means better
internal space and minimal leverage when loaded up.
New Berghaus FreeFlow Pro
We used the new FreeFlow Pro system at its launch in the
Lakes last week. The standard Freeflow uses flexible glass fibre /
Delrin struts which mean the air gap is easily compressed as the back
plate flexes. To prevent that happening, the new Pro uses a Nylon
backplate reinforced with two strong alloy tubes.
This means Berghaus can make the air gap smaller, so in turn, the pack
sits closer to the back for increased stability when loaded up. Like
Lowe Alpine - and Deuter who originated the concept - Berghaus has
removed some of the mesh to reduce contact area with the back. Finally
it too has a hip-belt that adapts to body shape.
At the launch we found it carries extremely well and unobtrusively and
there was no leverage even when scrambling. Finally, as promised the
air gap was relatively small, but still effective.
The Alternative - Gregory
Packs
At the recent Friedrichshafen OutDoor trade show, Gregory
was showing off its
new
back system which, like the discontinued Lowe
Alpine technology. Dubed Jetstream LTS, it uses a curved back plate and
alloy frame, but no mesh. The end result is a full air gap across the
centre of the back.
We haven't had a chance to use it yet, but bearing in mind the
deceptively limited breathability of mesh panels, it looks like an
interesting development and we're looking forward to trying it out.
Your Choice?
The main brands are getting better and better
at ventilated packs and minising the downsides by reducing air gaps,
increasing air contact with the back and improving load transfer
generally. All the systems we've looked at work far better than earlier
versions.
Our advice would be to try with a loaded pack before buying. The Osprey
system works well, but isn't cheap and has the edge for lightness while
the Lowe Alpine and new Berghaus packs share some similar features.
The Gregory, once it - like the Berghaus - is available in 2010 should
make for an interesting alternative to the mainstream options.
