[Trevor]

Here here Beav,

The sqeel is caused by simple mechanical reciprocal vibration (high frequency chattering) as you have previously pointed out. Violin bow, finger on wine glass, scraping metal, how could it be more simple.

Whistling, farting gasses what a lot of hot air and bull****. That is what the shims are for, ie to assist in reducing clearance and not allow room for vibration and they are arranged to provide spring tension to maintain a constant pressure. However it must be accepted that vibration can still occur resulting in noise in some circumstances. Exactly the same problem was present with drum brakes and was assisted by chamfering the leading edge of the lining.

However the snake oil accessory trade will always attract suckers particularly if they offer something different with eye appeal ( see what I have and you haven't stuff). My car goes faster than yours because my exhaust oatlets are chrome and pretty, etc. etc. etc. They should " Get real " as they say, lets leave them to it!

Trevor.