Just for information purposes.
.3mm is .011”, or basically the width of 2 sheets of paper.
Tolerances will probably be near +.1/-0mm on the wheel, and +0/-.1mm on the hub. They make millions of these, and the tighter the tolerance, the higher the scrap rate.
The wheel bore is not a full solid diameter. It has reliefs, if you look closely at the picture. This allows expansion for heat, and variances in diameters. Some will fit tighter than others, and not cause issues.
There will also be a tolerance on the position of the lug holes to the center bore. My experience was that the bore and outer tire mounting surface on the wheel were established at the same time, and the lugs were drilled afterwards. This will cause a bit of difference between the two centerlines.
If you expect that over the years of taking wheels off and on to rotate or change tires, that the mechanic is going to use precision to remount your aluminum wheel onto a steel hub, without dinging that bore more than the thickness of 2 sheets of paper, your expectations may be a little high. This is the second reason for the reliefs in the bore on the wheel.
So, if you feel unsafe because your wheels might be a couple thicknesses of a sheet of paper off-center, or too tight, then spend the extra cash on a better brand. I bought the cheaper ones, took the extra money and bought Brickyard 400 tickets, where I can watch pit crews slam lug centric wheels onto cars in mere seconds that drive 200+ miles per hour.
