On Sat, 27 Sep 2014 14:15:06 -0700, Joerg
wrote:

Folks,

Tried in a European NG but no luck so far. I get a nasty-looking red
skin rash on my shoulders and upper chest where the main carrying straps
of by hydration pack run along. I generally cycle in a thin T-shirt
because I can't take anything other than cotton. Gets totally sweaty, of
course. The backpack is a Zefal hydration pack and weighs about 12lbs at
the start of a ride, about 6lbs at the end after most water is consumed.
The rides are usually 3-4h long, sometimes strenuous and on rough
offroad terrain so the backpack jumps a lot.

Thick cotton layers over the straps didn't help much. Does anyone else
have that problem? Any ideas what to do?

That is 2.7 Kg of drink in 3 hours? Unless you are riding in the heat
of the day that sounds like a lot although that is also dependent on
how hard you are working.

But why not switch to bottles? You can get those behind the seat racks
and carry two on the frame and two behind the seat and the large
bottles would make up about the approximately 3 liters that you say
you are drinking.
--
Cheers,

John B.