I have just been looking at the trailer threads . Here in the UK most trailers have to have brakes on all wheels,the exception being if they are very small. I also saw that the bearings are fairly standard being of one or two sizes. Here trailers seem to be made by their manufacturers from all sorts of motor trade bits.the bearings being the worst. There are so many that the only place you can buy them is from a trailer spares shop,Even then its best to take the old bearing with you so they can get the numbers off them. At the moment Im trying to get some wheel studs and nuts for my 2001 trailer so far Ive not been able to get any,(threads wrong,wrong diameter,wrong length etc).So it looks like Ive got to start modifying the hubs to fit the studs. Who said boating was fun