We've talked about how to properly lock your bicycle before, but some bike racks -- particularly cheaper comb racks -- might require a few tricks. Here's what you need to do.
Obviously, the best thing you can do is lock your bike to something that's cemented in place, like a pole or a U-Rack. But if you're stuck with one of the more common grid or comb racks, things get a little trickier. We recently had some installed in my apartment building, and I had no idea how to lock them to the frame of my bike -- which, as we know, is the only way to keep it secure.
I found two tricks, posted online by Rich Swent (who took the above photos). Most people just put their front wheel in the "comb", but mount your bike with the front wheel over the top if you can, as shown below. That way, you can lock your frame directly to the rack (left image above).
If that isn't possible (some comb racks are too tall), try to grab a spot on the very end of the rack, so you can avoid the comb altogether and lock your frame to the side (right image above).
Obviously, a more secure rack is ideal -- so use one if you can -- but if you're in a pinch, one of the above tricks should work (as long as you're using a U-lock, not the easy-to-break cable lock). Remember, the goal is to make your bike more secure than the guy next to you.
Locking Your Bike [Bicyclist Education by Rich Swent]