As far as hydration pack ... I don't like to wear them on the bike either, but on the road bike, I let the shoulder straps all the way out and let the waist strap support the weight of the water on my hipbones. That's the only way I can wear it without straining my back. If needed, I CAN ride all day like that.
Nathan makes a hydration vest for MTB. I have no idea what it's like, but their running vests are EXTREMELY well balanced and comfortable, if that's any indication.
As far as triathlete water systems ... what about one of those frame mounted wedges with the straw? Expensive, but no more than a wearable pack. Would that leave you enough room for a second bottle on the seat tube?
Last edited by OakLeaf; 02-09-2013 at 08:11 AM.
Speed comes from what you put behind you. - Judi Ketteler