I've read several posts in the past which indicate backpacks are not a good idea for bike touring, but I'm wondering if anyone has tried the large, newly-designed hydration packs without the bladder.
I'm looking at the Dueter Cross Air (100 oz) as a replacement for my rear Topeak rack and trunk bag to go along with my Bob. Since I will doing a touring/mountain biking combo, I'd just as soon not have the rack on my bike when riding singletrack without the trailer.
The Cross Air has a mesh panel to keep the pack off your back and a 1350 cu in capacity.
Looks like a good design.

According to Deuter the airstripes system is better than the advanced aircomfort system for heavier loads as the advanced aircomfort's frame might dig into your back.

BTW, the Cross Air is only 22l, not 100.

Have you seen the Arkel Bug? It's a pannier that converts to a backpack. 1500 cu in volume.

https://www.arkel-od.com/panniers/bac...asp?fl=1&site=

Thanks. Yea, it's 100 ounces.

I think you are confusing the liquid capacity of the water bladder with the volume of space in the backpack. One hundred ounces is the amount of water the bladder will hold. Twenty two liters is the amount of space in the backpack.

Well, what I'm really wondering is whether these large hydration packs (Cross Air or Camelback Hawg) would be a significant upgrade over a conventional daypack for touring. I won't be using the bladder, so I'm really wondering about the pack itself.

I have a Deuter Trans Alpine 25l bag which I love. It's very well designed with the cyclist in mind. That being said, I wouldn't want to tour with it, or any other backpack for that matter, but for day trips it's perfect.

They also make a 30l version.

I have ridden with a small camelbak and discovered that I could only fill it about 2/3 full of water or it would start to be painful after about 30 minutes of riding. Even 2/3 full of water or less (because I drank the water), it gave me some serious pain after a while.

I have ridden with backpacks as well. For my 6.5 km commute in Winnipeg, my backpack was fine. But for my 30 km commute here, my backpack was NOT fine. I used it once and that was it.

Do a test, just grab any old backpack you have lying around your place, fill it with whatever you want to carry in the backpack, and do a ride of the distance you think you'll usually cover in a day. That should give you a pretty good indication of what carrying something like that on your back feels like. Even better would be to go out the very next day and repeat the same experiment. If it felt all right on the first day, it might feel quite different on the second day.

I ride with a cammelback pack to work - about 1hr each way and that's fine with a moderate load, but for a day in day out tour - no way. I definitely don't want any weight on my back and frankly that's what all the silly looking bags attached to my bike are for.

I do carry a Serratus Genie climbing pack in my panniers so I can go hiking and buy groceries when I need to. It folds amazingly small and works well as a pack when you need it. For those near a MEC Serratus is no longer and MEC is clearing these packs out at $39. They are a GREAT item for travellers and when they are gone they are gone. I know the Calgary store has a few left.

During my first tour, I was unable to get all my gear in the Bob drysac and still buckle it, so I used the topeak trunk bag.
What about strapping the backpack on top of the drysac for the fully loaded portions of the trip and using it for sidetrips without the Bob ?
For this type of use, what is the largest pack that would not be too cumbersome to ride with on occaisonal sidetrips ?
I'm looking at the Dueter Futura 28l 1709 cu in @ 2lbs 14 oz
and " " 32l 1950 cu in @ 3.8 lbs
" Cross Air 1350 cu in @ 2.8 lbs

Make sure whatever pack you buy from Deuter that it has the airstripes system (foam stripes molded on the back) rather than the advanced aircomfort system (the mesh thing that holds the pack away from your back).

Here's part of an email from Deuter that discusses the differences:

As for the back systems, the Aircomfort back system provides a maximum
of ventilation, since only the mesh has direct contact with the back
whereas the pack is kept in some distance. However, when the pack is
loaded heavily it is possible that the metal frame may be uncomfortable on
the hips.

The Airstripes back system with it's contoured foam stripes on the back
is more flexible and adapts better to the differnt back positions when
cycling. The pack has closer contact to the back, which may be of
advantage for balance when cycling in difficult terrain or when carrying
heavier load.