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E6X Looking for the correct offset

Discussion in '5 and 6-Series' started by CaStylin, May 11, 2018.

  1. CaStylin

    CaStylin New Member

    '10 535i, '09 X5 4.8l, '07 525
    Hey y'all... I need help!

    My desire is to run 20/30/295 or 20/30/305’s in the rear on my E60 535. Because of this desired size, the rim width has to be 10.5in or 11in. With a rim that wide, the offset must be perfect to avoid rubbing of the fender or any other contact points...

    And there lies my problem... while I recall seeing (on forums) multiple E90/E60’s running 295 and even a few running 305 running flush (no rub), I am having a hell of a problem establishing the correct offset for a 20/10in or 20/11in

    I'm thinking I could calculate the correct offset based on the popular opinion on forums that a 20/9in rims "should" have a +30 offset but I'm not even sure I'm doing that correctly so here is a scenario

    20/9in rim with +30 offset sits flush/no rub & I want to know what the offset would be on a 20/10 inch rim that also sits flush/no rub (i.e. just adding backspacing)

    If offset/ET is measuring the distance from the center of a wheel to its mounting face in MM and we know that 1in = 25.4mm is it proper to add 12.7mm (25.4mm/2 because we are looking at a new center) to the offset of the 20/9in rim and come to the conclusion that a 20/10in rim should have a 42.7mm offset? Did I do that right? Would that rim 20/10 et42.7 even fit?

    Any help is appreciated. Thanks again
  2. doublespaces

    doublespaces Administrator

    2009 E93 335i