I use an M-Wave D 8.6 Combination Lock, it is a combination lock-cable, weighs 2.4oz. For touring, people seem to respect what you are doing. In the past for most of my touring, I used my helmet. Just buckle it through the rear wheel and down tube. It will just stop someone from rolling off with your bike, since lifting it is unlikely. Never had a problem. the M-wave is a huge step up in security for me.