These Hub rings fit Light Truck wheels onto certain models. How to choose the right size: Check the Centre Bore (CB) data of the wheel you have on hand. This can be found on the box label. If CB cannot be found on the box or back of the wheel, measure the center hole?s diameter using a caliper. Inner Diameter (I.D.) should match the vehicles? center hub. Different vehicle comes with different hub size. The vehicles center hub will differ depending on year, model, make, and brand.Here is an I.D reference list? 77.8mm 78.1mm 87.1mm 93.1mmNot sure exactly what size hub-rings you need? Don't waste time and money guessing. Just send us a message with what wheels you have, what make, model, and year of vehicle you have, and we will be happy to recommend the correct hub-ring for you. How to install: Insert the Hub Centric Rings into the wheel center bore and then install the wheel onto vehicle wheel hub.Q&A Q: My wheel?s CB is 73.1mm. Can I use a hub ring Outer Diameter at 74.1? A: No. Must use the ones with O.D 73.1mm. Q: My wheel?s CB is 74.1mm. Can I use a hub ring Outer Diameter at 73.1? A: No. You can only use hub rings O.D 74.1 or sometimes marks as 74. Q: What is the tolerance of these Diameter data? A: Normally accept ±0.1mm. Like: 56.15=56.1; 60.06 = 60.1; 64.15 = 64.1; 66.06=66.1; 66.56 = 66.6; 72.56 = 72.6; 74=74.1 87.1=87.0 Q?I chose the right size, but Why can?t I push hubring into wheel, or push it onto Hub? A: Hub, hub ring, wheel are fit each other tightly, So they can?t fit in when there is rust or dirt on the Hub, or some rough edges of the hub ring or some paints over sprayed onto wheel center bore. So sand these slightly with a sand paper and try it again.