iv read up on hubcentricity..... but how do i tell if it fits or not without driving down the road and hearing a grinding?
also where would i get such rings?
OK, lets try this. Wheels bolt on to the hubs of the car. The hubs consist of a circular flat surface with bolts sticking out of it that go through the bolt holes on the wheel you are going to attach. There is also a circular raised portion in the center of this circle of bolts on the hub. With most (all?) factory supplied (OEM) wheels the hole in the center of the wheel is exactly the same diameter as the raised circular part of the hub. This means that the wheel is a reasonably snug fit over the center of the hub. This serves to locate the wheel precisely, even before the nuts are put on the bolts to fasten it there. This method of locating the wheel is referred to as 'hub-centric'.
For comparison, if the hole in the center of the wheel is larger than the raised portion of the hub then the wheel will be 'centered' by the bolts as the tapered nuts are tightened up. This is known as bolt (or stud) centric mounting. There is nothing inherently wrong or bad about stud-centric mounting, but hub centric is generally considered 'better' as it is less likely to cause vibration. If the wheels have a larger hole than the size of the hub you can usually purchase spacers to fill this void and make the oversize-holed wheel hub-centric. These are called 'hub-centric rings' and are available in a variety of sizes, hopefully a combo that fits your wheel/hub pairing. The ring has to have an outer diameter the same as the size of the hole in your wheel and an inner diameter the same as the raised portion of your hub. These hub-centric rings are generally available anywhere that custom wheels are sold and of course on eBay.
The problem happens if the hole in the center of your wheel is smaller than the raised center portion of your hub. Then the wheel will simply not go on to the hub
and lay flat against the mounting surface with the bolts in it. This should be immediately obvious when you try to mount the wheel.
So to summarize (whew!), if the the wheel hole and your hub center are the same size just bolt on the wheels and you're golden. If the hole in your wheel is larger than your hub just bolt on your wheel being careful to tighten the nuts in several progressive steps allowing the wheel to center itself on the bolts and you are golden. If you have trouble with vibration in this case, or just want to be sure, buy some hub-centric rings and use them. If the wheel hole is smaller than your hub center the wheel simply will not fit properly.