I had good results with the Wolfman Enduro duffel bag on the back of the 630's with out a rack. I used some 1"x18" soft-tyes handlebar straps and looped them under the seat and rear grab rails. The bags stayed put over 150 or so dirt miles. Cheap and durable. Here is a side view:
That's me standing next to my 630 with the stock Metzeler Karoos on. XLEnduroMan just put a set of 606s on his 630 and I have a set waiting to go on when the Karoos bite the dust. The bag set up was Great, stayed put didn't move a bit and I didn't have to give it a second thought. It was wonderful.
OH! i took the Karoos off after 50 miles and sliping around real bad in some gravel and grass. I forgot what they looked like.
