Helmet locking

[4gteen]

Usually, I take my helmet with me when I leave the bike. But sometimes that isn't convenient and I need to lock my helmet to the bike.
My other modern (well, modern-ish) bikes have helmet locks, but I don't see anything on my 401.
What are you using?

 

[Vintage Veloce]

I carry a short cable that I can loop and connect under the seat. Of course, a cable is easily cut, so I do not consider it very secure.

 

[Dr.Shifty]

A bicycle lock will do for a helmet, either a cable lock or U-lock. Something visible is a deterrent and helmets are not often the target for theft.

Most helmet locks on bikes are just a hook under the seat, it's the seat lock that secures it. You can make something up yourself. I've seen somebody do it with a single bolt screwed vertically into a frame member. Hook the helmet fastener over the bolt and lock down the seat.