Unfortunately, people often buy wheels whimsically, relying on the salespeople’s recommendations or guarantees from the wheel manufacturers that a set fits certain makes and models. A lack of research can endanger both your car and your wallet. Remember that many safety features rely on wheels: braking, suspension, steering, etc. So here are some specifications that should not be overlooked:
- center bore
- offset
- bolt pattern
Why Match the Center Bore Size?
Wheels are quite simple, but they are supposed to carry the weight of an entire vehicle. To do that, they must fit well. Your car or truck has a hub that connects the moving parts with the wheel. And each wheel has a special hole on the back, located in the center, where this wheel is attached to the hub. This hole is called the center bore and must perfectly match the hub, like a glove. Because otherwise, if the wheel center bore is too small or too large, there will be complications and issues.
There will always be enough options for you with the matching center bore sizes. But what should you do if the wheel set you want desperately has a different size? Obviously, that is not the best choice, but you can still fit such wheels with some extra work.
If the Center Bore Is Too Small
It would be a shame if someone ordered a set of new cool-looking wheels only to find out upon arrival that they are too small to fit the hubs. You can do two things with such wheels aside from returning them to the shop. You can take them to a professional to cut off some metal and make them bigger or use wheel spacers. Both options have pros and cons.
The first option is more expensive, costing about $200-$500 depending on the shop and its equipment. It requires special professional machinery not only to drill the metal but also to measure the diameter and distance to the center. Remember that the center bore must be located precisely in the center, or your wheels will get damaged over time, tires will wear out faster and alignment will be off-balanced. That is why you should never try that at home, even if you have some heavy equipment.
The alternative method, wheel spacers, is cheaper but also risky. Just like looking for a shop that has re-boring services, looking for high-quality spacers can take a lot of time. Many shops don’t recommend using them due to the poor quality of the materials. It really is a gamble sometimes. So look for old manufacturers with a good reputation and find some first-hand experience tips from other car enthusiasts.
If the Center Bore Is Too Big
Dealing with larger center bores is different. This situation is more common since most aftermarket wheel manufacturers tend to make their center bores wider to fit more vehicles. You can fit such wheels using special parts called spigot rings or hub-centric rings. They fill the free space between the center bore and the hub, making a smooth connection.
To choose the right one, look at the sizes. They have two diameters. The bigger one represents the center bore diameter, it’s the outer side. And the smaller number matches the hub diameter. Choose the ring that fits both, and you can mount wheels with bigger center bores without any issues.
Driving will cause noise and wheel damage if they don’t fit perfectly. The rings are not sturdy enough to withstand vibrations and shocks, so be extra careful. If you hear a weird noise, stop at the closest repair shop and let them check the fitment.
Why Offset Matters
Bigger or smaller rims often alter the offset or how your wheels sit in the wheel wells. You can go as far as 5 mm from the OEM wheels to stay safe. If you already use aftermarket wheels, do not apply this rule to them because they can already have an alternative offset value.
You can find the recommended offset measurements in your car’s manual, on charts and on a sticker on the driver’s door. This information is usually enough to make a decision. You can also use an online calculator. Just put the original parameters in one section and the new wheels’ parameters in the other for comparison.
Maintaining the offset within this recommended range is important to protect your tires and car’s body. If the offset is wrong, the wheel can come into contact with the wheel well, rubbing against the walls. If the offset is too different, you might have to make some modifications to fit the wheels you want.
Why You Should Know the Bolt Pattern
The wheel must be properly centered and secured in that position. But the center bore is not the only thing that ensures that. Currently, you can find two types of wheels on the market: hub-centric (wheels are centered by how well the center bore fits the hub) and lug-centric (wheels are centered by lug bolts).
Both types require the bolts to be properly torqued and sized, but the lug-centric wheels will be in greater danger if you get anything wrong. “Bolt pattern keeps the wheel centered and prevents vibrations and mechanical damage of your wheels and other parts connected to the wheel,” says Oliver Brown, Data Coordinator at Wheelssize.com.
Each car has its own correct bolt pattern carefully measured by the manufacturers. It has its functional purposes, like distributing the weight, providing a safer connection or centering. Choosing a set of rims with a different bolt pattern is risky.
Bottom Line
For many people, cars are more than a convenient means of transport, it’s also a hobby or an extension of their character. We take pride in polishing and perfecting things. And it’s hard to imagine what else can bring the same sense of fulfillment and pride as a good custom car build.
Usually, there are two main reasons why car owners opt for aftermarket wheels. It is either for aesthetics or for a boost in performance. But regardless of the desired end result, one has to follow certain guidelines to make a safe choice.
