I have a 30 foot log chain around the axle and a tree, tongue ball lock, pad lock on the tongue and a short piece of tempered chain and padlock through the wheel spokes and around the spring. I used to work for a construction company and trailers were being constantly stolen, thieves have some very sophisticated cutting equipment all you can do is slow them down and hope that it looks like it will take too long and go on to easier pickings.
Most receiver hitch locks are a joke also, my guys were constantly losing keys and most being hardened will break with a good blow from a hammer or slip a piece of pipe over it and snap it off. I now use a 5/8' Grade 8 bolt and drill the nut once its on and put a roll pin in.
