Heelsonwheels

oem's are forged and the replicas are cast

lylerichards

That being said, here is an explanation that makes sense.


Two different trains of thought going on here, and much debate about whats best. I'll give you a example coming from a machinists standpoint and automotive engine. Billet crankshafts are cut from a solid billet of steel, which means no stretching or hammering was involved in the making of the crank. Less stresses are placed on the material as there is no heat or distortion involved in the making of the component. One side of the fence believes a billet crank is stronger for it's weight, but can be more brittle, as the grain flow is cut rather than stretched.

The forged crank proponents want you to believe that a forged crank is better because the grain flow is more consistant. By this I mean, they want you to believe that when a hammer pushes the crankshaft throw out, the grain of the material follows around the corner evenly. The idea being that grain flow can bend a 90 degree corner and still retain it's original integrity. Forged cranks tend to take more abuse and bend before breaking, billet cranks tend to be tougher to a point and then crack. So really it's about grain flow and which part would fracture and which part would be more apt to bend.

On a wheel is this really an important factor? It depends on who you talk to and which wheel they are trying to sell you. Forged wheels tend to be a bit heavier and denser, because they have crammed more material in the same area. Billet wheels tend to be lighter and hold a finish more consistantly (if you were going polished). If you hit a deer at 140 with a forged wheel it would bend long before breaking, and if it were a billet wheel it would slice up more deer before shattering.

Cost? Well it's faster to bolt a chunk of billet into a CNC machine and wittle away a fancy wheel. With a forged, you have to compress the shape (roughly) then go back and machine the finish, and artsy fartsy shapes. Forged just has additional steps involved.

Cast is just poured into a mold, allowed to cool and then machined into shape. Cast means less waste as your not cutting away more that half of the material you started with. The problem with casting is it generally has to be much thicker and heavier to amount to the same strength as a billet or forged. Casting is not nearly as consistant for material grain and strength.

Now I paid $1800 for a Miro wheel and tire package, what is the worst that can happen. I bend a wheel. The finish starts to come off. I am not losing any noticeable performance that will make or break the car, if you guys can notice performance, hats off. An OEM wheel will get curbed, bent and scratched just like any other wheel will. I know I had an E39 M5 for 6 years with OEM wheels. Don't get me wrong I completely understand the manufacturing process for both wheels and that OEM has the superior quality, but it just comes down to priorities.

L

jvcajita

*brings out his encyclopedia on wheels and pushes it down the center of the table*

firstly, not all OEM wheels are forged and all Reps are casted as heelsonwheels mentioned...in fact, almost every single OEM wheel out there is definitely not forged. here let me give you an example...Lancer Evo's have OZ Racing OEM Wheels that are forged...anybody else can think of OEM Wheels that are forged?

secondly, one must fully understand wheel construction to say which wheel would be more reliable...you can't just simply say that an OEM wheel is always better than an aftermarket wheel. At the same time too you can't simply say that a more expensive aftermarket wheel is more reliable than an affordable wheel...here's some cool trivia for everyone...

GRAVITY CASTING
Gravity casting is the most basic process of pouring molten aluminum into a mold utilizing the earth's 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
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 dense) over a gravity cast wheel. Low-pressure casting has a slightly higher production cost over gravity casting. Low pressure is the most common process approved for aluminum wheels sold to the O.E.M. market. Low-pressure cast wheels offer a good value for the aftermarket as well. 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. Once again in the quest for lighter weight, there is a higher cost associated with the process.

SPUN-RIM, FLOW-FORMING OR RIM ROLLING TECHNOLOGY
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 its 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. BBS has used this technology for several years in their production of racing wheels for Formula One and Indy cars. BBS's RC wheel for the aftermarket is an example of a wheel produced using spun rim technology.

FORGED OR SEMI-SOLID FORGED
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. Semi-solid forging (SSF) is a process that heats a billet of special alloy to an almost liquid state and then the aluminum is forced into a mold at a very high rate. The finished product offers mechanical properties very similar to a forged wheel without the high production and tooling costs of a forged wheel. When low weight and performance are on your priority list, the SSF technology offers an excellent value. Currently only SSR (Speed Star Racing) from Japan is licensed to use this process for the production of wheels.

http://www.tirerack.com/tires/tiretech/tec...e.jsp?techid=90

now with that info at hand, you gotta find out how a wheel your purchasing is manufactured. I'll tell you off the bat that NOT ALL OEM wheels are forged...BMW NA give us forged? uhm no way when a US Spec Car is typically a non-staggered setup while our Euro counterparts are still staggered. Its one of the many ways they try to cut cost...so if they go this route what more for actual production? another example would be Miro Design. I know personally that all the wheels in that line up is low pressure casted...which is actually the most common process that OEM manufacturers use...the difference between the two is the logo ur buying into...marketing cost you could say...prestige is also another factor...

but please, don't be part of trend just because...you need to be educated on your decision making through text, content, and also through self experience or experience of others...

btw, +1 on the previous post about forge being bendable and casting being crackable...they all pass US Market standards...so either way, the legitimate ones are safe...it's all about preference...

pointerman

You can always buy refurbished OEMs from someone like Detroit Tire and Wheel for the same price you would pay for an aftermarket wheel.