To find out the outer bore of the your wheel you will need to measure the center hole from the back of the wheel. You need to measure the actual hole and not the taper. The picture below shows which bit is...
To find out if your alloy wheel needs "Tuner" style or "Standard" size bolts/nuts simply measure the hole size. The tuner style holes are normally around 2" width the standard size is normally around 3" Most...