[PeterAllen]

Mine uses 3 3/8 bolts. The shear force required to break these is way more than the traction of the tyres can hold.[/quote]

Is it the bolts that shear or would the latch mechanism and/or the hinges, even with spreader plates, pull out of the fibreglass?

One thing in my favour is that I'm running narrow wire wheels and narrow period size tyres. The down side is they might get me into trouble in the first place!