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Are OEM modular wheels stronger than 1pc OEM wheels?

Discussion in 'Technical Q&A' started by cwwhk, Feb 8, 2004.

  1. cwwhk

    cwwhk Formula 3

    Nov 13, 2003
    1,535
    Hong Kong, Tokyo
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    Wayne
    Are present day modular wheels actually stronger and lighter than one piece wheels? This was the case many years ago, but current wheel manufacturing processes are so advanced I am not sure if the modular approch is still valid.

    My understanding is that the center piece of the modular wheel is forged, the rims are usually rolled or forged. Forging creates dense and uniform grain structure therefore allowing thinner and lighter design.

    However, now a days we have forged or low pressure casting one piece designs. Without the need for rivets or bolts (even if titanium) surely the forged one piece design will be stronger and lighter than the modular ones. No???

    355 came with Speedline magnesium (not sure if forged or not) one piece wheels that were exceptionally light and strong. Saw first hand how well they stood up to impact in a track day event. The 550 also came with Speedline magnesium wheels before the recall to switch to aluminum ones due to nut seat cracking. I like the look of the modular OEM wheels, but would like to find out if they are actually stronger and lighter before spending big bucks for just looks alone.


    Thanks.
     
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  3. chaa

    chaa F1 Veteran

    Mar 21, 2003
    5,058
    Kin ell!! Acording to his profile this guys got 5 ferraris? Im going to check out his web site.
     
  4. Auraraptor

    Auraraptor F1 World Champ
    Lifetime Rossa Owner

    Sep 25, 2002
    11,470
    MO
    cwwhk, Very interesting thoughts, can you post a picture of the Mag. Speedlines? How much do they run a set? Thanks
     
  5. 348paul

    348paul Formula 3

    Dec 27, 2002
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    Paul Hill
    If I had to chose what would be strongest it would be a Billet/Rotary forged centrepiece with spun work hardened rim halves and Ti Nuts & Bolts! (Grade 23 ELI !)

    I suppose its down to the quality of the centrepiece - I seem to recall a certain manufacturer using this rotary forging process that created a radial grain structure. A cast component will be a lot less shock resistant compared to a billet / forged item. We have all seen pictures of cars that have been in accidents where the rims of cast alloy wheels have literally disintegrated under impact. I find it quite frightening that some of the wheels that are on the market hardly look as though they can take the weight of the car! - I suppose the FEA software that the manufacturers use these days allow these wheels to be trimmed down to the bone (quite scary IMHO!)


    Paul
     
  6. cwwhk

    cwwhk Formula 3

    Nov 13, 2003
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    Wayne
    The magnesium Speedlines are the regular 5 spoke OEM wheels you see on 99% of the 355s. I think the 355 Challenge style 5 spokes are also magnesium Speedlines, but I don't have a picture of that wheel.
     
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  8. Auraraptor

    Auraraptor F1 World Champ
    Lifetime Rossa Owner

    Sep 25, 2002
    11,470
    MO
    Interesting. What are your thoughts on the F512M mag 2 piece rims? I was thinking of getting a set, as they are my fav. design.
     
  9. cwwhk

    cwwhk Formula 3

    Nov 13, 2003
    1,535
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    Wayne
    Paul:

    In theory if both are regular forgings, would you say the 1 piece forged wheel is stronger and lighter than 3 pc modulars. For instance OZ Racing has the 1 pc Forgiata and 3 pc modular Superleggera III. Both are basically the same 12 spoke design, except the first is forged 1 pc, while the latter is forged 3 pc modular.

    I am thinking the 1 pc would be stronger since the grain flow from center to rim is continuous in the 1 pc design.

    I agree with you that some of the new wheel designs do not look to be too safe. IMHO it's not through the magic of FEA, but merely sacrificing strength for looks.
     
  10. cwwhk

    cwwhk Formula 3

    Nov 13, 2003
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    Wayne
    I love the look of those too, but.... I think those still have SS screws along the edge of the rim. Adding mass at the edge of the rim, where rotational inertia is highest just does not seem like a good idea to me. Actually that's another one of my concerns regarding modular wheels that made me start this thread.
     
  11. 348paul

    348paul Formula 3

    Dec 27, 2002
    1,098
    Kent - UK
    Full Name:
    Paul Hill
    Without seeing a cross sectional view of both rims it is difficult to say 100%. It would be very interesting to see a view of the forged wheel and 3 piece to compare the difference!


    Paul
     
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  13. Mitch Alsup

    Mitch Alsup F1 Veteran

    Nov 4, 2003
    7,176
    I will note in passing that all the top F1 teams use forged Magnesium wheels since <?somebody?> developed the forged (casting) process for magnesium in the mid-late 1990s. I remember reading an F1 article about how Ferrari used to get 2-5 races out of the previous technology and started getting a whole season out of this new technology.

    I should also note that magnesium wheels should be X-Rayed every 5 years to check for eminent fatigue failure <especially if the car is tracked>.
     

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