United Kingdom transport research laboratory has estimated that in the UK alone, 7,500-11,000 wheel fixing defects are recorded annually (considerably more go unreported).
45% due to failed wheel studs (due to fretting)
23% worn studs (due to fretting)
13% stripped threads
4% corroded studs
15% other defects
The consensus of opinion remains the same. insufficient clamping force is the main reason wheel assemblies fail.