Originally Posted by amanlikemike
The US-30 is actually only around 2" longer than the US-20, so it shouldn't be an issue - especially with the new Alloy Hook Straps, which enable the pack to be secured further back at the rearmost point of the subframe, where it will not shift forward. So the difference will be negligible at the most
However, if you do find that the 30 is encroaching on your seat space, you could always mount it across the saddle, as opposed to in-line with it, which will actually give you more room than you already have with the US-20. The only downside to this configuration is that you can't then mount a US-20 on either side. But this still leaves you with the option to stack your US-20 on top of it (or indeed another US-30) and possibly use a US Tank adaptor to mount a second US-20 on the tank to get your 70 liters that way.
Personally, I tend to travel as light as possible and generally just use a UScombo40 on the tail, with a 10 or 20 on the tank and any camping gear etc strapped to a rear rack (my bike is something of a workhorse and I went for a Renntec one). Alternatively, a rear rack could be used to carry more US packs.
I hope that helps, but feel free to post up any more questions you may have.
Thanks Mike. I am attempting to avoid a rear rack. Which is where the Kriega's really come in. So most things will need to fit inside the bags to properly mount. I might eventually break down and buy a rack, but just think the Bonnie's look really cool without personally.
I wonder if I could do what you suggest with fitting a 30 across the saddle (90 degrees), and then attach 1 bag above and 1 bag behind. Either 30+30+20 or 30+20+20. That would give plenty of room. Have you heard of this configuration working?