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The ultimate Wheel Thread! Differences between CAST, FLOW FORGED and FORGED Wheels.

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    The ultimate Wheel Thread! Differences between CAST, FLOW FORGED and FORGED Wheels.

    Hey Guys,

    since i get this question alot from friends, group Members and customers on a daily basis i thought that i am going to make a thread with the full explanation about the differences of the types of wheels that are available in the Market. I will do this my way, so it may be a little bit funny to read at times but i hope you enjoy. The main reason i am doing this is to educate those that do not have the knowledge yet in order to be able to compare apples to apples and not apples to banana. And mainly that people understand that not all wheels are the same and thats why there are significant price differences.

    I am not posting this to start a discussion but more to share my own experience and also to share facts. I have used some data from the Internet as sometimes it is simply on point.

    So lets do this :)

    1. What do Cast, Flow Forged and Forged wheels have in common?

    - Well if you re lucky they are all round and they will bring your car from A to B, however in a different way. Consequently, all wheels are not made the same. The performance of an alloy wheel is a direct result of the manufacturing technique employed.

    2. What is a Cast wheel and how is it manufactured?

    - There are 2 ways of Casting a wheel.

    The cheapest of all is called 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. Some final machining work is then done to clean up the rough surface, and paint/finishing is applied. These are the lowest priced wheels. 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. Cast aluminum is not very dense, and so greater weight of metal is needed for strength. So this is the cheapest of the cheapest wheel you can buy. Cost of manufacturing these is as cheap as it gets, but interestingly enough it comes at a price! Whenever you pore a liquid in a "container" you WILL have air bubbles. Due to this Gravity Cast wheels are the weakest of all. They are not very durable, they tend to crack or worst case scenario fail completely. Most of the "replica" wheels are gravity casted. They are the heaviest, the weakest and probably the worst thing you can add to a high performance vehicle. They are also very very difficult to balance to 100% even with high weights as the quality standards are low.

    The biggest factories for Gravity Cast wheels are in china.

    Pros: Lowest price, easiest to mass-produce.
    Cons: More brittle than forged wheels. Spoke details and edges aren't as sharp as a machined forged wheel. Heaviest weight of all wheel construction types. Lowest quality. Limited offsets, width increments, diameter selection available. Nearly impossible to repair when cracked or severely bent - safely, that is. A damaged cast wheel usually needs to be replaced

    Below is a picture of the process.


    photo upload

    Here is a great acticle about "FAKE" wheels compared to OEM Wheels : Are fake wheels safe? Holden & Mercedes team up to find out | PerformanceDrive!



    Below are some pictures of failed "Replica wheels" Do you really want to run something like this on your car?














    gif upload

    The 2nd cheapest way of casting is low pressure casting. Low pressure casting is widely used to manufacture "Branded" cast wheels. And yes there are big well known brands that sell their cast wheels. And yes they are low pressure casted and made in China. If you will look at the wheel or on the box, it will always say made in China and they do not mean the box they come it ;). 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. However, you can buy "good" low pressure cast wheels. If you are only after the looks and you do not care about performance, weight and fitment this is an OK option. Yes they are still heavy and fitment is limited so you mostly going to have to use spacers to have good fitment but they are a better choice than gravity casted wheels. Most of the OEM wheels a re low pressure casting technology which pretty much suits the purpose. However, they are still heavy and not as stong as forged wheels. NOTE: OEM wheels of high performance vehicles are FORGED! So sometimes when you have a high performance vehicle you pretty much downgrade from what you have on the car from the factory by putting cast wheels on.

    3. Flow form wheels

    - Flow-Formed wheels start out identical to cast poured wheels, but with different hoop thickness. The casting process above is used to create the spoke pattern only. Then the wheel castings are put into a flow-forming machine to form the outer hoops. This is done using high heat and high pressure rollers, which "flow-form" the outer hoop. This results in a stronger outer hoop, with aligned aluminum grain structure. The resulting wheel is a cast faced wheel with a hoop that has properties similar to a forged wheel. They are stronger and lighter than cast wheels, but yet not as light or strong like a forged wheel. But once again you will have fitment limitations as also these type of wheels are mass produced and NOT built to order. Some OEM Manufacturers use this technology. If Budget does not permit a custom tailored forged wheel then the flow form wheel would be the 2nd best option. But there is still quite a Gap between a Flowform and a Forged wheel.

    Here is a Video of the Flow Forming Process: Flow forming wheel machine LW 3 245 proces 02 - YouTube


    Pros: Low Pricer than forged wheels, Lighter than cast wheels, Higher strength than cast wheels.
    Cons: Cast face still lacks the sharp edges and details of a machined forged wheel. Limited width increments and diameters available. Hard to repair when severely bent or cracked.


    3. Monoblock Forged wheels

    - 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 be very light, in fact the lightest of all wheels! The costs of tooling, development, equipment, etc., make this type of wheel very exclusive and usually demand a high price in the aftermarket. The term "Monoblock" is used throughout the industry to describe the 1-piece forged wheels. "Mono" meaning one, and "Block" meaning it was created from one block of aluminum. The block in this case is actually a round bar stock of high quality, aerospace-quality 6061-T6 Aluminum Alloy. The round bar is pressed in a huge forging machine, to stamp out a wheel shaped blank. Forging is a hot working process, and helps to align the grain structure of the alloy. This results in a very strong, very lightweight wheel construction material. The wheel blank is then flow-formed to create the outer barrel shape. Following that process, the wheel blank is loaded into a CNC milling machine and there the spoke pattern is milled out.

    Forged wheels are built to order and custom tailored to your needs. Therefore, PCD, size, widht, offset, color combination can all be specifically manufactured as per your needs. It is the lightest and strongest of all, can be made in perfect fitment! Hece it comes with a price. Typically the ONE Forged blank alone costs more then 4 cast wheels, finished, painted, packed and ready to go. Not to mention the engineering and machining costs to build a wheel. When we talk about weight this is a big factor when it comes to forged wheels. Weight on a wheel changes the rotating mass, therefore as lighter the wheel, pretty much as faster the car. Steering is lighter and the overall performance is much better. Believe it or not, a car with a forged wheel has less rotating mass that the engine has to moove and therefore puts down more power than a car with a cast wheel. Marginally but measurable! Most of the OEM Wheels on high performance vehicles are forged, and yes they do come on some of the M Power cars from the Factory. Once gain, anything less than a forged wheel would be a downgrade to the existing wheel you are running on your car. Most of the well known forged wheels factories are in the USA. However there are some in China and Taiwan, so ask where the wheels are manufactured as they are some differences. Mainly with the Raw Material used, the Quality Control, Engineering and LOAD TESTING! Asian Made Forged wheels tend to be much cheaper than US Made Forged wheels. Yes there are also many Factories in Japan and Europe as well. So make sure where your wheels are coming from!

    Pros: Lightest of the forged wheel construction methods.
    Cons: Price and Manufacturing Time.

    Now lets get to the weight differences of a FORGED and a Cast wheel. Yes this is my favourite part now :)

    OEM BMW Design 162 wheels have been weight on another forum on a calibrated to medical scale digital Scale!

    18x8 Front = 30 lbs each
    18x8.5 Rear = 32.2 lbs each

    As a Comparison yesterday i weight my 19 Inch AMP Forged Monoblocks yesterday.

    8.5x19 Front = 22 lbs each
    11x19 Rear = 24 lbs each

    So here we have the following

    The Front AMP Monoblock forged wheels are 0.5 inch wider and 1 inch larger but weigh 8 lbs less even though being the larger wheel!
    The Rear AMP Monoblock forged whels are 2.5 inch wider and 1 inch larger but weigh 8.2 lbs less even though being the larger wheel!

    So that is a total weight saving of 32,4 lbs!

    Now you might say, ok this is not a good comparsion. So lets get a better comparison.

    Since there are many M3 drivers here lets take the OEM e92 M3 FORGED wheel made by Fuchs! This is probably the greatest comparison since this wheel is forged as well

    8x19 Front = 27,8 lbs each
    9.5x19 Rear = 29.2 lbs each

    AMP Monoblock Forged wheels

    8.5x19 Front = 22 lbs each
    11x19 Rear = 24 lbs each

    The Front AMP Forged Monoblocks are 0.5 inch wider than the BMW OEM M3 Forged Wheels but still weigh 5.8 lbs less
    The Rear AMP Forged Monoblocks are 1.5 inch wider than the BMW OEM M3 Forged wheels but still weight 5.2 lbs less

    Total weight saving : 21,7 lbs

    So if you would take the same sized wheel you can imagine that the weight saving would be even higher.

    Below is a some pictures of how forged wheels are made.


    image upload









    imagur

    3. 2-Piece Forged wheels

    - 2- Piece forged wheels are pretty much manufactured the same as the Monoblock forged wheels except that they are mashiened out of 2 seperate pices which are then bolted togoether.There are many different type of 2-Piece forged wheels. For example with welded centers, bolted cast centers and so on but the ones which i are the most common in for the well known brands are the ones with a forged center and forged barrel. A 2-piece wheel in this configuration pretty much looks like a Monoblock Wheel but with exposed Hardware (showing Bolts) If you do not want the bolts to be seen it is also possible to make them with non exposed hardware so the bolts will not be visible. So there is NO LIP! Yes there are 2-Piece wheels with lip but those are not the ones i am reffering to. Now the question is, why a 2 piece wheel? Mostly because with a 2 piece wheel in some applications you can run a more concave profile. On some applications, NOT on all applications. Its also easier to have 2 tone finishes.

    Pros: More Concave Profiles, exposed hardware (bolts) if wanted, easier 2 Tone finishes.
    Cons: slightly heaver as the Monoblocks mainly due to the Hardware that is used to bolt the wheels togoether, also a bit more pricey do to the hardware and assebmly costs

    Below is an example of the same wheel design in Monoblock and in 2 Piece. Dont mind the color though






    imgurl


    3. 3-Piece Forged wheels

    3-Piece Forged 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, for example widebody applications. 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. Three piece forged wheels are usually the most expensive wheel construction, mostly due to the assembly labor and components used. The wheels consist of three main pieces; the center, the outer barrel (lip), and the inner barrel. These three parts are held together with a series of perimeter bolts. Silicone RTV is used to seal between the two hoops. Some manufacturers also offer cast aluminum centers, to reduce cost. Quality and weight of the cast centers is not as good as forged/machined, however. So be careful when you buy a 3 piece wheel and ask about the Materials used for the Centers. With that being said, most of the high quality forged wheel use forged centers!

    Pros: Most width increments available, truly perfect fitments available. Easiest of all wheels to repair if lip gets bent or damaged, as hoops are easy to replace. Easy to paint or chrome plate lip, when required since every piece is separate. Highest resale value for used wheels. Highest concave profiles
    Cons: Most expensive forged wheel construction. Heavier than Monoblock or 2 Piece wheels but STILL much lighter than Cast wheels.


    Below are some sample pictures of how a 3 piece wheel looks like and what it consists of.






    image upload


    3- Piece wheels always have a Lip. This lip can be a flat lip or a Step lip depending on your taste.

    The Gunmetal Gray wheel with polished lip as a FLAT LIP. The Gloss Black with Candy Red lip has a STEP LIP.






    photo hosting


    So i hope this helped a little bit and clears up alot of thoughts and questions on the WHEEL Topic. As you can see the only thing all these wheel types have in Common is that they are round :)
    sigpic

    Simon Motorsport L.L.C
    Dubai Investment Park 2
    The Curve Building Complex
    Warehouse No.1
    P.O Box 28638
    Dubai, United Arab Emirates
    Contact: +971559564303
    Office: +97148830851
    Web: www.simonmotorsport.com
    Email: Franz@simonmotorsport.com
    Facebook: https://www.facebook.com/simonmotorsportdxb
    Instagram: http://instagram.com/simon_motorsport_dubai#

    #2
    Nice Write up Franz !

    Very Very informative , STICK THIS THREAD ADMIN !

    2008 E90 M3 6MT - Nardo Grey - Harrop TVS1740 SC @ 6.5PSI - UCP Pedal - Bullet Valvtronic Exhaust
    - Rouge Engineering Shifter Kit - Fabspeed X-pipe - Evolve test pipes - DEFI CR gauges/P3 Vent Gauge -
    BMW Iconic Custom Headlights - Custom Authentic Alcantara Interior .. And many other mods :P

    1996 SC300- AT- SOLD
    2012 Toyota Fortuner - DD
    1994 Toyota Supra MKIV - 883 WHP ;) drag queen - Track only

    Comment


      #3
      Originally posted by E90_M3_6MT View Post
      Nice Write up Franz !

      Very Very informative , STICK THIS THREAD ADMIN !
      Thanks bro :) only took me half a day to do it LOL.

      But i think it will help people to choose the right thing while purchasing something and especially to do the right comparisons.
      sigpic

      Simon Motorsport L.L.C
      Dubai Investment Park 2
      The Curve Building Complex
      Warehouse No.1
      P.O Box 28638
      Dubai, United Arab Emirates
      Contact: +971559564303
      Office: +97148830851
      Web: www.simonmotorsport.com
      Email: Franz@simonmotorsport.com
      Facebook: https://www.facebook.com/simonmotorsportdxb
      Instagram: http://instagram.com/simon_motorsport_dubai#

      Comment


        #4
        Great info!! thank you for sharing :thumbsup2:
        sigpic

        Jerez Black 2008 E92 M3 - The beast unleashed

        History:
        Black 2005 E46 330ci Mtech2
        Silver 2003 E46 330i Mtech2
        Black 2002 E46 320i Mtech2
        Black 1986 E28 535i
        Burgundi 1986 E23 728i
        Blue 1985 E30 323i Mtech
        Hellrot 1981 E21 325i

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