How does one lock their bike when on a tour and stopping at a grocery store or restaurant? There are actually quite a few options here. At the most basic level we can assume that most people are honest and the main purpose of locking the bike is to keep them that way. If a crack head or junkie wants your bike they will probably get it unless you use a stout, heavy lock such as a U-Lock. But these are heavy and it’s difficult to justify carrying that extra weight.
I have read a suggestion somewhere that a person can simply strap their helmet through the wheel and frame. If a thief tries to take off with the bike they will be caught up short and abandon the project. A slightly more secure option might be to use a leather or nylon toe strap, the kind used on pedal toe clips, the same way.
My personal preference is to use a thin braided steel cable such as the Kryptoflex with a keyed padlock. I don’t think I would trust this arrangement in a high or even medium-high crime area, and definitely not for locking the bike overnight if it was out of my sight. Somewhere I heard that motorcycle gang members will use a padlock with a bandana tied through the shackle as a weapon, like some sort of medieval flail. I hope I never have to use my lock that way, but there is that option.
Most times I can arrange to be seated in a restaurant where I am able to keep an eye on the bike. Even on tours when I have not brought a lock or when I forget the lock back at camp, upon arriving at a grocery store I often roll the bike in and ask if it’s OK to leave it in the front area inside the store. I have never been refused, in fact in Danville, CA the woman I asked told me I could roll it inside the customer service area.
The next level of security can be had with a braided cable lock of a larger diameter. These come in keyed and combination versions. Any braided cable lock can be cut fairly easily with a sharp pair of wire cutters or bolt cutters, so the determined thief can still get your bike.
The greatest security might be had with a U-Lock. These locks have hardened steel shackles which are impossible to cut by most mechanical means, and secure locking mechanisms. The dis-advantages are the heavier weight and the fact that the size and shape of the shackles limits the versatility as far as objects to attach to.
The best defense against bike theft is to be careful, and always assume that someone will think they deserve your bike and gear more than you do.