BMW riders are some of the most likely to be wearing a helmet — and some of the least likely to have a place to put it. I’ve always been frustrated by the lack of a helmet lock for my bikes. Lately I’ve been trying the Helmet Guardian and it’s become one of my favorite gadgets. It’s kinda boring (I’d rather add a GPS or something else fun) but it does the job. It’s pretty inconspicuous and securely holds two helmets.
Here’s an action shot from Cycle Gadgets — the bike I have mine on is a bit torn apart right now.