are they a necessity? do you need use them? what do they do?

They help keep the rim centered on the hub. Most aftermarket rims have a larger than stock centerbore, that puts all the weight on the lug studs.. A hub ring helps by adding that spacer into the centerbore to 1) keep the rim centered and 2) transfer some of the weight of the rim to the hub -- meaning, less chance of shearing the studs.

what size should we use?

V Dub wrote:"Portion control my ass. Good thing she's not a psychiatrist. Oh, your addicted to alcohol, oh you're addicted to crack? Well next time you get that crack rock...... just smoke half of it."

http://www.j-body.org/forums/read.php?f=42&i=31356&t=31356#31356

Quote:

You just need to know the Cavaliers Hub Diameter (57.1mm) and your aftermarket wheels Hub Bore.

Lots of good info in that link too

searching is like a lost art

StrippedCav98 (Now Quotable) wrote:searching is like a lost art

Are you surprised?