I'm not sure whether this is relevent or not, but Zulu's just finished so I feel like swinging the lantern.
During my Boy Racer days, I bought a set of alloy wheels off Ebay (kurbed to feck, but I still thought I looked well 'ard with 'em on) and put standard studs on them, and bought some locking wheel nuts to go with them..
Anyways, about a month or so later every time my rear wheel would rotate 360 degrees it would make a knocking noise. I thought this would be a bearing in the brakes or something (not much else can go wrong with the arse end of a FWD car) and after a week or so of driving about like this I decided to have a look..
Upon inspection every single steel nut had worked its self loose from the hub, with ONLY the flimsy locking wheel nut holding it on. So every time the wheel would turn, it would come away from the hub, and then bounce back and "knock" it, making the noise.
Now I do quite a bit of motorway driving and with only a single locking wheel nut stopping my wheels from popping off at 70mph I was a lucky bugger indeed!
Now, after a swift change of underwear, the first thing I did was DRIVE (yes, with the same nuts tightened up a bit ) to the nearest scrappy to get some alloy wheel nuts, thus stopping natural selection from successfully killing off the less intellegent of the species (IE: Me).