10 mil will rub too.
I was having a bit of drive in the north york moors and on the some of the more severe compressions, the back tyres give a rub. Going to have a look at fitting a smaller screw myself. The road I was on was a bit of a rally stage and very bumpy, on day to day driving i've had no probs!
Whoever it was that mentioned when they rub you end up pulling a bit of a face was dead right!!!!