Generally, the wheels of cars and trucks, and actually most roadgoing vehicles, have a hole in its center. This hole is called the “center bore” and its main function is to seat the wheel onto the vehicle hub properly and securely. Therefore, it is important that the center bore of the wheel matches or is a little bit larger in diameter than the vehicle’s hub size for it to be seated properly. It prevents vibration, resulting in more fluid steering (for the front wheels) as well as a smoother ride (for all the wheels).
Aside from the center bore being a guide for seating the wheel, center caps prevent dirt and grime from entering the hub assembly. It is also a way to reduce the wheel weight, according to some car enthusiasts. Other car nuts say it’s there to allow access to the wheel hub without having to take the wheel off. Still, other car gearheads say the whole is a part of the manufacturing process and allows for mounting the wheel over several kinds of wheel balancing equipment.
Whatever the reason is, wheels have holes at their centers, and while most cars come from the factory or dealership with wheel center caps fitted, some center caps can and do get dislodged and lost.
This brings us to perhaps the main reason why your wheels need center caps: they make the wheels look complete and great. Admit it; wheels without center caps really don’t look nice. Cars and trucks with missing center caps look poorly maintained, run-down, and unattractive.
Whether you lost your wheel center cap because it came loose, or they broke because they’re already old, or you just want to change the look of your car or truck, replacing them is very easy.
There are three ways to find the proper size of your wheel center cap:
1. By using the part number of your center cap and ordering it from a dealer or online; you may also take your vehicle to the dealer, pick one from their selection, and attempt to fit it directly onto your wheel; this is perhaps the easiest way to replace center caps
2. By measuring the center bore of your wheel
3. By measuring the dimensions of the old or original wheel center cap
For option 2, follow these steps:
Step 1: Take the diameter of the wheel’s center bore using a vernier caliper. Using this will give you the most accurate measurement of the center bore. However, you will need to know how to use a vernier caliper to make the correct measurement. If you don’t have a vernier caliper, take a ruler and lay it flat across the center bore. Place it at the approximate middle of the bore and take the measurement. Repeat the same step at different positions around the diameter and average out your findings to get the most exact measurement. Round this number up or down.
Step 2: Take your measurement to the auto supply or accessory store and find a center cap whose flange matches the measurement of your wheel’s center bore (you can find instructions on how to measure this in the next option).
For the third option, there are three measurements to make for the proper fixture on the wheel. Perform the following:
Step 1: Take the old center cap and place it on a flat surface, making sure the open end is facing up.
Step 2: Using a ruler or steel tape measure, measure the inner diameter of the original center cap. This is the distance between the inner walls of the center cap. As in the first option, try to get several measurements and average them out to be more accurate, round the final measurement up or down, then list down the final measurement.
Step 3: Look for the widest portion of the cap, and measure this part. This will be the outer diameter of the center cap. Again, measure this several times and average them out to get a better final measurement. List this down.
Step 4: Measure the depth of the center cap. To do this, hold the center cap and insert the tape measure into the opening until the edge of the tape measure meets the plat inside portion of the cap. Take the measurement from the bottom part to the edge of the opening. To get a better result, place a ruler (or anything thin, flat, and hard) on top of the opening and take the measurement from where the tape measure meets the edge of the ruler. List this down.
Step 5: Take your measurements to the auto supply or accessory store and look for a wheel center cap that exactly matches your measurements.
Wheel center caps are usually designed simply. Most have the car maker’s logo embossed or stamped on its face. Aftermarket center caps may have smooth, blank faces to allow for customization by attaching decals on the flat surface. Whether you’re getting original equipment wheel center caps or aftermarket ones really depends on your taste. However, if you do decide to get aftermarket center caps that have a different design from the original, it would be a good idea to choose a center cap whose design still matches or complements your vehicle’s styling. Imagine putting a futuristic-looking center cap on your vintage car. That would definitely look rather off, wouldn’t it?