Do Internal frame packs lead to sweaty backs?

[Paul455]

As my children have grown up I can switch from an 80L pack to something lighter. Considering a 50L Atom The Mo but wonder if internal frame packs create a problem with sweat build up?

[Neo]

I always get a sweaty back to some degree, using different packs in hot or cold weather.

Grooves for venting and the trampoline style harness are a bit better.

I don't let it bother me, best has probably been the design of the Exped Lightning, it has a nice lumbar pad and then touches on my upper back leaving good air flow.

[GregG]

Yes

[Petew]

I get a sweaty everything! A trampoline style harness is a bit less sweaty but not amazingly so. I have a MO and it's a fantastic pack. Reasonably light and durable.

[JohnnoMcJohnno]

Being a hot sweaty bloke I mainly use an external frame pack and an Exos to try and avoid hot sweaty back syndrome. I do have an Osprey Xenith which uses a grooved back panel - not as good as a trampoline back but its not bad. The Xenith also has a mighty hip belt so you can loosen the shoulder straps and promote some air flow. I also have a Granite Gear Crown (the massdrop version) which is miserable on a hot day. It uses a flat panel in the back. Even though its grooved, it's way hotter on the back than any other pack I own.

Someone mentioned the Lightning. Don't have one but the back support system certainly looks like it will help with air flow. However I'm not sure those Exped packs qualify as internal frame. The frame support is definitely outside the pack.

[ChrisJHC]

Every pack I’ve ever worn has given me a sweaty back. I am a fairly good sweater!

I used to wear a cheap cotton T-shirt while hiking then change into a dry top when I stopped for the night.

I then joined this forum and learnt that I would die if I wore cotton so now I wear an expensive merino T-shirt while hiking then change into a dry top when I stop for the night.

[Warin]

[quote="ChrisJHC"]Every pack I’ve ever worn has given me a sweaty back. I am a fairly good sweater!

I used to wear a cheap cotton T-shirt while hiking then change into a dry top when I stopped for the night.

I then joined this forum and learnt that I would die if I wore cotton so now I wear an expensive merino T-shirt while hiking then change into a dry top when I stop for the night.[/quote

Cotton works well for hot sweaty conditions. Only when it gets cool does cotton pose a problem.

Using a cotton T=-shirt while sweating and then changing to something dry when the sweating stops would be fine.

[crollsurf]

I had an Exos where the pack sits off your back but still got sweaty. As someone pointed out, sweating isn't the real issue, it's getting too hot, so the Exos works well in that regard. Plus an external frame, you're still going to sweat on the shoulders and hips.
The other option for up to 4 day walks is to go UL. Then you can sling your pack on 1 shoulder for a time, to let the sweat on your back evaporate.

Also like Warins explanation, cotton is nice.

[Huntsman247]

I think the key thing to avoiding sweat is avoiding the pack altogether and not combine it with any physical activity. Lol.
I've got an osprey pack that has one of those suspended mesh backs and my shirt will be completely saturated whenever I take the pack off.
The difference I've noticed is that due to the mesh design the pack doesn't absorb as much sweat which leads to a less smelly pack.

[Lamont]

As my children have grown up I can switch from an 80L pack to something lighter. Considering a 50L Atom The Mo but wonder if internal frame packs create a problem with sweat build up?

Every rucksack causes sweat. You're not going to avoid it. The Exos Crolly referred to will stop you from completely becoming saturated in many cases-it did for me.
You walk with a hot weight on your back you'll sweat. My best solution to this is to dress appropriately-use a good Nylon fishing shirt that dries very quick- it will dry in a blink and as Crolly said, something UL is likely to also be much smaller so less there will be less fabric is in contact with your back. The Atoms all come with Cordura back panels-that's hot stuff but probably no hotter than any other material. Go for it going from 80L to 50L(which is actually a 40L) you'll think the world has changed, colours will be brighter, birdsong will be all the sweeter.
The Mo is the about same as the Wilderness Threadworks Ossa I think-Atoms are 3 months on the wait (they shut to make masks fir a time) apparently not including posting time which I'd reckon from experience will be at least three weeks.