If you put velcro all over the disc it would not look anymore cool which is one of the most importat factors in using clear hubcaps
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Also the hubcaps needs to hold on at top speed whatever the car has. In europe the topspeed is restricstred on most cars to 250 km/h. If the hubcap is not perfectly centerer velcro is little bit loose on side Z-axis and at high speeds that does not end well.
I will do a quick test to at least 180 km/h and see what the results are. If someone wants to go even faster that ok with me but on spec sheet it is told you to what speeds hubcaps will last...