Want to source some mag wheels for our 1970 beetle convertable but am not sure of what questions to ask when it comes to buying through the trading post or ebay. At the moment there are 4 stud P185/70 R14's on it. What are the questions I need to ask of an advertiser of mags as I understand not all 4 stud mags are the same. Been stung once with rims where the stud holes were out by a bee's whatsit bought over ebay. Any help out there???

make sure the PCD (pitch circle diameter) and wheel offset match up with your cars specifications then you should be ok.

That's 4x130mm for late-model Beetle. You need to check offset, too. Different original and aftermarket wheels have different offsets which makes them poke out or sit under the guards more

Basically any wheel not made for a 4 stud beetle will not be able to fit. eg you will be limited to beetle specific wheels, such as empi's , etc. drop a line to one of the large vw shops.

Thanks BiX, VWCOOL, blutopless2 and the u2u from *did* for the responses, what is the PCD and how do I measure it? Is it (excuse me for asking like I'm a 9 yo) for example if the four studs were lined up in a cross pattern, one north, one south and one each at east and west, take a measurement from N to S, OR E to W, it comes out at 130mm. From any diagonal stud to another?

Can't find too much in all the books I have on offset either, is that the width of the imprint? At the moment the tread footprint made is 15cm or 19.5 cm from wall bulge to wall bulge. The tyres only just show outside the guards now. (avatar not much help there)

Yes you are right about PCD (Pitch Circle Diameter), it is simply the diameter of the circle of the bolt pattern. All 4 stud Beetles and Type 3's have 130mmPCD.
Offset is the measurment from the wheel mounting flange or surface to the outside of the rim, therefore if the wheels have too much "offset" they will protrude outside the mudguards.
Similarly "backspace" is the measurement from the mounting flange of the rim to the inside of the rim. Too much "backspace" could see the rims fouling on suspension or stering components.