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Mountainsmith lumbar pack tensioning and maximum load

February 23, 2021 — BarryK

Continuing to investigate the carrying capacity of the Mountainsmith lumbar packs. See earlier posts:

Here is a video posted by Paul in 2013. He is a thin guy like me, and he carries up to 11kg in his lumbar pack:


...oh man, does he ever carry a lot of stuff! However, he has a shoulder strap to stop the bounce.

Paul's Day pack is an old model, apparently made from lighter material, before Mountainsmith went over to "Cordura" fabric, which is made from recycled plastic bottles.

It seems that Mountainsmith have moved their entire range of lumbar packs to Cordura, which may be why they dropped the Daylight model.

The problem is that the Cordura packs are much heavier. But, I guess Mountainsmith are going for the "green credentials" rather than minimizing weight.

I looked carefully at Paul's video, his pack doesn't seem to have the tensioning straps, which would be why he had issues with the pack falling away from the back, and lots of bouncing.

That tensioning strap system is called "Delta Wing Compression Strap" and was patented by Mountainsmith in 1996, see this image from the patent application:


The image is from here:

Yes, my Daylight pack has that same 2-strap tensioning system. Weird that their redesigned Daylight model in 2016 uses only a single strap -- and I have already commented that I think that is less effective.

Interesting that both Paul and Drew claim that a shoulder strap can be setup so that it does not pull on the shoulders, just pulls the upper-pack toward the back. 

Tags: light