For 83-85 Riviera Base Convertible (2) 1.5" 5x4.75 Hubcentric Wheel Spacers

How to choose correct wheel spacers/ adapters? 1. Check Your Vehicle/ Wheel Bolt Pattern/ PCD - 5x4.75" or 5x120.65mm The bolt pattern of a wheel is the layout of the mounting holes. A wheel's bolt pattern can also be called its "Bolt Circle" or "Pitch Circle Diameter (PCD)" Bolt pattern is expressed as the number of lugs by the diameter of the imaginary circle formed by the center of the lugs. For example, 5 x 4.5 in., or 4 x 100mm The bolt pattern MUST match the pattern on the axle hub. Even a slight difference will cause the wheel to be off-center. This will cause excessive vibration while driving 2. Check Vehicle Hub Bore Size - 70.5mm Measure the diameter of the center bore, make sure the spacer's diameter is the same as the axle diameter 3. Check Vehicle Thread Pitch - 12x1.5 There are different types of studs, sunch as M14X1.5, M12X1.5, 1/2"x20, 9/16"x18, please make sure the studs of wheel spacers is the same as the vehicle's, otherwise the spacer will not fit 4. Measure the fender gap to choose suitable thickness. - 1.5" or 38mm The thickness of spacer you need will vary depending on the individual vehicles you’ve performed, determining that correct thickness is extremely important Measuring the wheel gap is the most basic beginning. The wheel gap is the amount of space between the inner fender lip and the outside edge of your wheel tires or rims The main reason for vibration from wheel spacers 1.Sometimes wheel weights get knocked off or lost when pulling wheels on/off the car 2.If the wheels were out of balance, the spacers would magnify the effect 3.Its possible that the wheels didn't seat correctly on the hubs. Lowering the car more than was necessary to keep the wheel from turning How to fix the problem ? 1. Firstly, getting rid of the problem of wheel spacers themselves and making sure everything was mating up correctly. For example,wheel bore should match the hub.When the wheel is in the air, give it a spin and check for any misalignment/wobble/etc.Both the face of the wheel hub and the back of the wheel spacers are clean,no rust or corrosion. Maybe it is just a small burr on one surface.Make sure wheel bolts are long enough and are torqued and retorqued after a few miles.After check it,pls try to remove them and re-install 2. Rebalance or correct an out of round condition of your tires Following the above step,removed everything, cleaned/inspected for any small dents/gashes in the wheels/hubs/spacers, put everything back together and torqued the bolts in a star pattern with only a bit of weight on the wheels but it’s still vibrating.Then it’s certainly the vibration wasn’t caused by wheel spacers but there is an existing imbalance or out of round in a tire of your car.Then you need to go for a rebalance.Finding a technician that actually understands how the tire balance works. Most better shops can handle this. Just go in and ask if the technician knows how to overide the automatic zero or whatever its called. Expect to pay extra for the additional time it will take.If the tire may be out of round, in which case a small amount of shaving will be necessary. If you find a shop that can correct an out of round condition, we’ll assume they also understand balancing to less than 1/8 oz.And the problem is now almost gone 3. Very smooth roads don't cause any vibration. After rebalance or correct an out of round condition of your tires,any vibration left its entirely road induced.Very smooth roads don't cause any vibration