Originally Posted by cyccommute

All of my racks have built in locks. The fork mounts have lock cores that lock onto the fork and the hitch rack I have has a hasp mechanism that covers over the top tube and locks in place.

That said, a cable can be pretty effective. It worked well enough for these 4 bikes that fell off the back of an RV near Devil's Tower


I couldn't get the bike loose or I'd taken them for what parts I could salvage.