This little snippet of info may save people a lot of anguish. I just hope that it won't get "bounced" by some "difficult" administrator (I have had so much trouble with this that I may have to start my own website as being thwarted in my attempts to give out free information gleaned in a lifetime of engineering is rather annoying to say the least)
Ever noticed that bicycle pedals have opposite handed threads? The reason is to prevent the pedals unscrewing themselves owing to "precessionary forces". Regrettably handing of threads is seldom seen on wheel nuts nowadays. The new idea is that if the nuts are tight enough they will never unscrew. Whilst this works OK for millions of people everyday it is bad engineering especially on "lugcentric" wheels (wheels located by the studs - not sitting on a centre spigot). The real problems occur when what are basically bubble car wheels or minicar wheels are used on trailers. The tyres can be upgraded to 6, 8, or even 10 ply rating but the studs and nuts were never really designed for so much weight. Add in a few potholes and an 800 mile round trip and problems are likely to occur. Invariably it is the left hand wheels that come loose. Reverse engineering the design by manufacturing lefthanded nuts and studs is not easy as high tensile steel is needed so what can be done? New studs and nuts do help as these can be tightened to a higher torque than old rusted worn nuts and studs. Threadlocking compound also helps tremendously. If the studs are long enough, locknuts can be fitted, this is easy to do and highly recommended and it is also possible to use Nyloc nuts as locknuts . (these dodges are only needed on the left hand side) In some motor racing circles the scrutineers demand that wheel nuts be drilled and wired as used to be done on aircraft and the practice does have merit. Curiously the problem of wheel loss is not restricted to small domestic trailers. Allegedly thousands of wheels are lost each year in the UK alone and the bigger wheels can cause fatalities. Good Luck!