the hubcentrics can stop vibrations but are not always neccesary for all models. I had a pair of 17 in Tenzo tantrums and didnt need them but on the chrome Alba 17 in. wheels I have I needed them. From what I can tell it helps take up the gap between the hub on the brake assembly and the wheel. If there is a gap it will leave room for play. all they do is take up that space. if you can afford them and there is a gap I would suggest getting them. your local tire centers usually carry them fairly inexpensive.