Though not enforced, there are quality standards to govern the production of wheels. Some countries though, like Germany and Japan, have government regulations requiring aftermarket wheels to meet certain criteria and ensure proper fit. The United States has taken steps to establish guidelines but it will be some time before they can enact regulation of any kind.
Consequently, all wheels are not made the same. The performance of an alloy wheel is a direct result of the manufacturing technique employed.
iD Select offers a wide range of wheel choices from manufactures that have adopted the manufacturing processes that meet the strict O.E.M. (Original Equipment manufacturers) requirements. Wheel companies that supply to the O.E.M. market must follow certain procedures during the manufacturing process to maintain the quality and integrity of their product.
"...all wheels are not made the same. The performance of an alloy wheel is a direct result of the manufacturing technique employed."
There are many factors to consider when purchasing an alloy wheel.
It may seem obvious, but a wheel is comprised of a hub, spokes and rim. Sometimes these components will be one piece, sometimes two or three. The hub is the center portion of the wheel and is what attaches the wheel to the suspension. The spokes radiate out from the hub and attach to the rim. The rim is the outer part of the wheel that holds the tire. While many people refer to wheels as "rims," this is technically incorrect. Well discuss several ways that wheels are manufactured below.
This is the most common type of aluminum wheel. The casting of wheels is the process of getting molten aluminum inside a mold to form a wheel. There are different ways this can be accomplished and although it sounds simple, this is truly an art when done properly.
Gravity casting is the most basic process of pouring molten aluminum into a mold utilizing the earths gravity to fill the mold. Gravity casting offers a very reasonable production cost and is a good method for casting designs that are more visually oriented or when reducing weight is not a primary concern. Since the process relies on gravity to fill the mold, the aluminum is not as densely packed in the mold as some other casting processes. Often gravity cast wheels will have a higher weight to achieve the required strength.
Low pressure casting uses positive pressure to move the molten aluminum into the mold quicker and achieve a finished product that has improved mechanical properties (more density) over a gravity cast wheel. There is a slightly higher production cost over gravity casting, but low pressure casting is the most common process approved for aluminum wheels sold to the O.E.M. market. Some companies offer wheels that are produced under a higher pressure in special casting equipment to create a wheel that is lighter and stronger than a wheel produced in low pressure, but theres a higher cost associated with the process. Low pressure cast wheels offer a good value for the aftermarket while still maintaining strength and a lighter weight.
This specialized process begins with a low pressure type of casting and uses a special machine that spins the initial casting, heats the outer portion of the casting and then uses steel rollers pressed against the rim area to pull the rim to it's final width and shape. The combination of the heat, pressure and spinning create a rim area with the strength similar to a forged wheel without the high cost of the forging. Some of the special wheels produced for the O.E.M. high performance or limited production vehicles utilize this type of technology resulting in a light and strong wheel at a reasonable cost. O.Z. has used this technology for several years in their production of racing wheels for Formula One and Indy cars. O.Z.s Formula HLT wheel for the aftermarket is an example of a wheel produced using spun-rim technology.
The High Light Technology (HLT) process used in the manufacturing of select O.Z. Racing wheels uses rollers to compress and elongate the material along the barrel of a low-pressure cast aluminum wheel to obtain the desired profile. This process, which is directly derived from O.Z.s experience in F1, produces wheels that are extremely light and strong.
CNC Mill. In forged wheels, computer numerically controlled (CNC) mills add the cosmetics and the bolt circle to exacting tolerances.
The ultimate in one-piece wheels. Forging is the process of forcing a solid billet of aluminum between the forging dies under an extreme amount of pressure. This creates a finished product that is very dense, very strong and therefore can be very light. The costs of tooling, development, equipment, etc., make this type of wheel very exclusive and usually demand a high price in the aftermarket.
This type of wheel utilizes two or three components assembled together to produce a finished wheel. Multi-piece wheels can use many different methods of manufacturing. Centers can be cast in various methods or forged. The rim sections for 3-piece wheels are normally spun from disks of aluminum. Generally, spun rim sections offer the ability to custom-tailor wheels for special applications that would not be available otherwise. The rim sections are bolted to the center and normally a sealant is applied in or on the assembly area to seal the wheel. This type of 3-piece construction was originally developed for racing in the early 1970s and has been used on cars ever since. The 3-piece wheels are most popular in the 17" and larger diameters.
There are now many options for 2-piece wheels in the market. The 2-piece wheel design does not offer as wide a range of application that a 3-piece wheel allows; however, they are more common in the market and the prices start well below the average 3-piece wheel. Some 2-piece wheels have the center bolted into a cast or cast/spun rim section and other manufacturers press centers into spun rim sections and weld the unit together. When BBS developed a new 2-piece wheel to replace the previous 3-piece street wheel, they used the special rim-rolling technology (originally developed for racing wheels) to give the rim section the weight and strength advantages similar to a forged rim. On the high-end of the 2-piece wheel market you can find wheels using forged rims and forged centers. Since these are only sold in small volume and due to the high development and production costs associated with the forging process, they tend to be on the high end of the price scale.
In addition to coming in many different sizes and designs, wheels come in all different styles of construction and composition. Here are a few of the most important compositions and methods for wheel owners to know about.
Steel is both heavier and stronger than aluminum, and has been used for wheel construction a great deal longer. Steel bends and becomes damaged much less easily than alloy. Because steel is already so strong, further casting or forging methods are generally not necessary. Most steel wheels are stamped out by massive presses and then welded together to form the wheel, as in these steel racing wheels. The downside to this is that steel will not allow for the kinds of spoke and face designs that make allow wheels such an artistic platform on the car. For the most part all one can do with steel faceplates is to stamp some windows in them for brake cooling purposes. However, several companies nowadays are working hard on creating steel wheels that are chrome-clad, meaning that they have a thin overlay, usually made of tin, which has been chrome plated and then glued on the face of the wheel.
Many Ford and Chevy pickup trucks now come with chrome-clad wheels as standard options.
Aluminum alloy is a mixture of aluminum and nickel. The proportions of metal in the alloy determine both the strength and weight of the wheel. Less nickel in the alloy means a lighter wheel, but one which is more pliable and easier to bend in an impact. More nickel means a heavier wheel, one that does not bend easily, but may be more brittle and prone to cracking.
Cast aluminum is just what it sounds like – molten alloy is poured into a mold and allowed to cool. Several types of casting methods exist, but what they have in common is that cast aluminum is not very dense, and so greater weight of metal is needed for strength.
The simplest form of casting metal is to pour the molten metal directly into the mold. This also creates the least dense metal, as only the force of gravity is pushing the metal into the mold. Gravity-cast aluminum alloy must therefore be thicker and heavier than other methods in order to have enough strength to be used safely for wheels.
There are two types of pressure casting in use, low pressure and counter pressure casting. Low pressure castings uses air pressure to force molten metal into the mold. This causes the molten metal to pack itself into the mold with more density and greater strength. Counter pressure casting uses the opposite process – creating a mild vacuum inside the mold, which literally sucks the molten alloy into it. The results are basically the same for either process.
Flow Forming is a hybrid process in which low pressure cast aluminum is stretched and formed using heat and high-pressure rollers to shape the wheel. The stretching and forming process creates a thin and dense metal which has properties similar to forged aluminum.
Forged Aluminum is created by taking a solid “billet” of aluminum alloy and subjecting it to a tremendous amount of heat and pressure, usually about 13 million pounds of pressure, in fact. The pressure simply crushes the metal into the desired shape. The forged blank can then also be flow-formed to shape the barrel. This creates a wheel that is extremely dense and enormously strong, but also very light. Pound for pound, forged aluminum is orders of magnitude stronger than a cast aluminum alloy.
Rotary Forging is a brand new process. In rotary forging the aluminum billet is forged under the same kinds of pressures, but is done while the forge is spinning at high speed, and often at an angle. The centrifugal force involved causes the molecular structure of the metal to reform in circular chains that are strongly bonded together. This creates a wheel that is even stronger against radial impacts than conventionally forged aluminum. TSW is rather cagey about their process, but it seems to also involve some variant of flow-forming, with rollers on each side of the barrel that forge the metal still further.
Wheels might seem like the most mindless part of your car to modify, but if you care about making whatever it is you drive any better, youve got all sorts of things to think about beyond how they look. Besides whether or not a wheel might bolt into place and fit, youve got to consider it's weight and rigidity, shape and design, manufacturing process, and what sort of material it's made out of. It's all of those things that can mean the difference between you hard-parking your Civic at your next boba shop meet or chilling in a ditch on the side of the road because of some slipshod knock-offs that all of a sudden came apart.
The time to stop thinking of wheels as nothing more than some sort of aesthetic improvement is now. Switch to something lighter, wider, or of a different diameter and you just mightve made one of the biggest improvements you could hope for. Get rid of enough weight and all of a sudden your car just got a whole lot faster. Size things up properly and get ready for increased mechanical grip at the tires.
With the exception of heavy steel slugs youve got no business caring about, most wheels are made out of aluminum or some mixture thereof. Aluminums relatively inexpensive and, when compared to steel, exhibits a higher strength-to-weight ratio. In other words, aluminum wheels can be strong and light.
Just how strong and how light they are, though, depends on how theyre made. There are only a handful of ways wheels can be manufactured, the most popular of which are a couple of different types of casting processes, flow-forming, and the most expensive of all, which accounts for the sort of wheels that keep you up at night, forging.
The results of whatever material your wheels are made out of and how exactly theyre manufactured will determine how well and how safely your car will perform. In the world of wheels, light weight and high rigidity wins; skimp on either and youve just passed up one of the simplest ways of making your car better.
Speaking of bunk wheels, you might think youre outsmarting science by wrapping a set of high-dollar R-comp tires around your knock-off wheels, but know that the better a tire does it's job, the harder the wheels got to work, which can result in premature failure and all sorts of collateral damage that will make the $500 you saved by skimping on rims not so big of a deal anymore
Wheels can be cast in two ways: by means of gravity or through a low-pressure application. Gravity casting is the simplest and least expensive process. Here, molten aluminum gets dumped into a mold where it's spread, set, hardened and turned into a wheel. No forces other than the Earths pull pack the aluminum into place, which means gravity-cast wheels arent the strongest.
Low-pressure casting applies a vacuum onto the molten aluminum, packing it's molecules into place, reducing impurities and resulting in a denser, stronger wheel. If whatever car youve got was originally sold with aluminum rims, chances are theyve been low-pressure cast.
As it turns out, aside from being heavy, those OEM wheels arent all that bad. Government regulations require original-equipment rims to be a whole lot stronger than they really need to be—at least twice as strong as recommendations for aftermarket wheels. Speaking of aftermarket wheels, here, regulations arent enforced outside of places like Germany or Japan, which means you sourcing your next set from a reputable company with some sort of racing pedigree just got a whole lot more important.
Also known as spun-rim manufacturing, flow-forming starts off like low-pressure casting but finishes with a whole lot of heat and a series of steel rollers that finalize the wheels shape. What you end up with is something almost as strong as a wheel thats been forged but for a little less money.
In terms of strength and durability, forging cant be beat. Forged wheels begin life as hunks of billet aluminum that are heated up and compressed using all sorts of expensive machinery until they resemble a wheel. Billet aluminum is about as dense as it gets, which means more material can be removed, resulting in something extremely light but without sacrificing strength. The results can lead to a wheel three times stronger than something cast yet weighing as much as 25% less. The forging process also allows for less material to be used, which means larger brake components that typically wouldnt clear now do thanks to a potentially lower-profile design.
Finally, theres roll-forging, which starts with a rough-cast wheel and is pressed into its final shape while rolling. The process allows roll-forged wheels to use thinner materials, which can lead to even less weight.
Every wheel consists of a hub, some spokes, and a rim. Multi-piece wheels are made up of two or three sections that when assembled make up a complete wheel. In some cases, multi-piece wheels can be made up of components that each underwent different manufacturing processes. For example, a two- or three-piece wheels center section can be cast or forged while it's rim is spun. The advantage here is versatility. Three-piece configurations allow manufacturers to offer a whole lot more sizes that would typically be cost-prohibitive with casting. Because of the way multi-piece wheels are bolted together, theyre often heavier than similar one-piece versions and sacrifice some rigidity.
You know that the lighter your car is the better itll accelerate, stop, and do just about anything else you ask it to. But what you dont know is that lighter-weight wheels also improve your cars unsprung weight. Were talking about all of those pounds that arent supported by the cars suspension, such as it's brakes, tires, and wheels. Reduce unsprung weight enough and get ready for more communicative steering and better turn-in characteristics when pushing it to the limit. According to Lee, heavier wheels mean slower throttle response, longer braking distances, and an overall less-nimble steering feel.
You already know that offset determines where a wheel sits laterally, but what youre missing is just how crucial it is to whether or not your carll handle like rubbish. Whoever designed your cars suspension went through all sorts of trouble to make it steer, turn, accelerate, and stop the way they thought it ought to. As it turns out, a wheels offset has a lot to do with all of that. Alter it enough and youve just told the engineer who developed your cars suspension that the scrub radius he implemented isnt all that important to you. It should be, though. It's the scrub radius that allows for traction differences between your two drive wheels, which can keep you in a straight line and out of that ditch. Modest offset changes wont result in these sort of shenanigans, though, and can often be implemented guilt-free in hopes of fitting wider wheels and tires into place. Vos advice? Stick to something as close to what the factory thought it ought to be in the first place in order to avoid rubbing, poor handling, and premature wheel hub failure.
This ones simple and reflects the amount of weight each wheels capable of supporting. Find the number, which is typically expressed in kilograms, multiply it by four, and expect it to be a whole lot bigger than your cars actual weight. Be sure to account for any sort of aero mods that increase downforce—and the amount of weight applied to the wheels—as speeds increase.
It doesnt get any simpler than identifying a wheels diameter and width—which is typically expressed in inches—than by peeping the identification sticker. Look for something along the lines of 16x7.0 or 18x9.5.
Now that you know why you ought to care about offset, look for the numbers following the "OF" or "ET" (German abbreviation for offset) on the sticker to determine what yours is. To keep all of this as complicated as possible, offset is typically expressed in millimeters, not inches, and may look something like this: OF +38.
Someplace on the identification sticker youll find a lone letter or three that, no matter how hard you try, will mean nothing to you but happen to represent the complex contour of the wheels flange and whether or not a safety humps been integrated into it's shape.
You recognize the series of numbers following the "PCD" but, until now, didnt realize that PCD stands for pitch diameter circle, or your wheels bolt pattern.
Most stickers include even more information thats specific to whomever made your wheels, like letters or numbers that indicate their color, finish, or lug count.
The difference between aluminum and alloy wheels is quite confusing to a few, but in fact, an alloy is just shorter, and used as an alternate word for aluminum wheels. Aluminum rims or wheels, alloy wheels and aluminum alloy wheels, are all different names of the same entities.
Aluminum and alloy wheels are different names of the same entities.
Alloy wheels are lightweight and corrosion resistant.
Aluminum and alloy wheels are also used for cosmetic purposes, and for racing cars
Aluminum and alloy wheels are stronger, and can be painted or left as they are.
Some of the types of aluminum or alloy wheels, such as forged aluminum and carbon fiber wheels, are extremely expensive.