315/30/18 on Challenge rim | FerrariChat

315/30/18 on Challenge rim

Discussion in '348/355' started by F355Bob, Mar 24, 2011.

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  1. F355Bob

    F355Bob Formula 3

    Has anybody mounted 315/30/18 on a Challenge rim? It seems like you need at least a 10.5 inch rim but I seem to remember guys using this size on Challenge rims.
     
  2. fatbillybob

    fatbillybob Two Time F1 World Champ
    Consultant Owner

    Aug 10, 2002
    29,277
    socal
    Yes I've done it on my own tire mounting machine no less. I would only do it if say you were running scrubs for cheap like us SCCA T1 racers still racing C5's use that size and sell the scrubs off. Problem with running 315 on 10" rim is that you pucker the sidewall and actually loose sidewall support and contact patch on the ground because the tread ballons up and you have to run artficially low pressures to get some kind of even heated contact patch. So best stick to proper size for 8.5" front and 10" rears and you will actually be faster. Although you can tune a car for just about anything if you try hard enough.
     

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