ok so whats the verdict??

All I have changed is the wheels, Titans off,Volans on.
so why all of a sudden am I losing wheels???
Its been suggested the nuts dont fit the wheels correctly and are coming loose, but they worked fine on the Titans???
maybe that the Volans are 7 spoke, instead of 5, so less cooling??
Im getting mixed views about the causes, but it has to be fixed permanently, so I am safe,the marshalls are safe and my wallet can stay closed for a while.

As I am now running out of wheels and tyres, I will be needing replacements,so will be looking at getting some 18s. can anyone see any problems with those, before I have any more accidents????

thanks in advance for any sensible comments