I have towed trailers all my life, a few years ago the count here was seven owned by me (now much reduced) and I hold HGV 1 which for non UK people means articulated trucks of any size, trailer maintenance has always been kept up by me, and my self built three bike/cargo trailer has been to Breganze three times in recent years, but yes, I got nicked in Austria for speeding with it and the fine came to me in the UK eight months after the offence, 112KPH it was and perfectly stable, even the wind/weather can alter that mind. I have demonstrated it fully loaded at 160KPH.
I did have a failure on the last trip back which is worth mentioning, a wheel very nearly came off! as DoC Booth and I were approaching our overnight stop in Switzerland (the house of engineer/scientist, Amicale friend, Patrick Fugelister of nuclear power fame) we heard and felt something not correct, so we stopped, and yes the OS wheel had two snapped studs, one missing nut and one still holding but loosed, and very "ovalised" bolt holes in the wheel, swapping a nut from the NS wheel gave us two to tighten, and three remaining on the other, a desperate repair.
The two wheels were from a Austin Mini of maybe 1962 vintage, and although looking to be OK, they were not, they were an accessory popular at the time, made by Weller for autograss, autocross racing etc , how old were they, I don't know but the wrong side of 40 years in my ownership anyway, the problem was that they had got progressively thinner and thinner, and eventually the nuts had started to "pull through" I was aware of this, but didn't think hard enough about it. At Patricks we fashioned a better repair using the spare wheel and two M10 bolts, and nylocs, the wheel is centred not on its hub as is more common today, but by the countersink and the 60 degree cone faced nuts The (second) temp repair got me the 600 odd miles to home. Patrick had a super heavy duty toe jack, which meant we didn't have to unload the two triples,500 kilos between them probably.
Later I bought new wheels x3 and tyres, specific trailer type now, and it shocked me how thick the metal was!, new studs all round and new nuts, but this time the nuts are all drilled and lock wired, I even carried a grease gun to give the bearings a shot on arrival at Breganze,(it stays in the car at all times) but payed far too little attention to the actual wheels themselves, very lucky that it did not end badly. picture shows trailer with old wheels, Chrissiewissy might have one showing the new wheels.
Moral being don't take the actual wheels for granted, they are of as much importance as anything else.
CLEM