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Thread: Question for suspension experts...

  1. #1
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    Question for suspension experts...

    Guys, I have a buddy who recently had his '98 M3 Coupé go through a tire installation and alignment at WheelWorks. When he was finished and showed me the alignment report, his report showed different tolerances than mine when I went for my alignment a month ago at the same place. My car's a '99 and we both have a coupé, staggered config, same rims, same S-03s.

    Here are the tolerances for both of our cars. My question is, which one is telling the truth? Sources pointed me to Bimmerforums for some expertise on this question.

    Thanks in advance.


    (Items in red are discrepancies)

    His car: 1998 M3 Coupé
    ======================

    Fronts:
    Camber: -1.3° to -0.3°
    Caster: 7.1° to 8.1°
    Toe: 0.13° to 0.21°
    Cross Camber: -0.5° to 0.5°
    Cross Caster: -0.5° to 0.5°
    Total Toe: 0.25° to 0.42°

    Rears:
    Camber: -1.9° to -1.6°
    Toe: 0.13° to 0.21°
    Total Toe: 0.25° to 0.42°
    Thrust Angle: -0.05° to 0.05°


    My car: 1999 M3 Coupé
    ======================

    Fronts:
    Camber: -1.4° to -0.4°
    Caster: 6.1° to 7.1°
    Toe: 0.04° to 0.12°
    Cross Camber: -0.5° to 0.5°
    Cross Caster: -0.5° to 0.5°
    Total Toe: 0.8° to 0.25°

    Rears:
    Camber: -1.9° to -1.6°
    Toe: 0.21° to 0.29°
    Total Toe: 0.42° to 0.58°
    Thrust Angle: -0.05° to 0.05°
    BRACEYOURSELF
    It's gonna be a hell of a ride...

  2. #2
    Join Date
    Mar 2001
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    1970 Cadillac DeVille
    I don't have my Bentley manual in front of me, and can't recall exactly which set of data is right.

    But, you may want to look at the "Sport" alignment specs here.
    In the slow lane

  3. #3
    Join Date
    Apr 2001
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    That's why I hate the chain shops, like WheelWorks. When it comes to alignments, you're at the mercy of the guy who enters the data into the computer, and most of the guys who work there don't work on enough BMWs to know whether or not the computer is spewing out the right info. Anyway, enough of that. Here are the specs from Bentley for a 3.2L M3:

    Front:
    Toe angle (total): 0 degrees, 10' +- 5'
    Camber: 0 degrees, 46' +- 30'
    Caster @ 10 degrees: 9 degrees, 35' +- 30'
    Caster @ 20 degrees: 7 degrees, 50' +- 30'

    Rear:
    Toe angle (total): 0 degrees, 30' +- 6'
    Camber: -1 degree, 45' +- 10'
    Max allowable camber deviation between sides: 0 degrees +- 3'

    You need to convert the Bentley specs from degrees/minutes/seconds to decimal to compare it to your data.

    I wouldn't worry too much about the tolerances - they're really just a guide to give most people warm and fuzzy feelings. Be more concerned about the actual numbers - what are they, and how much do they deviate from side to side.

    Jim
    Last edited by Jim O.; 05-29-2002 at 03:00 PM.

  4. #4
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    Split-up after "Door to Door" album was launched
    Originally posted by Jim O.
    Front:
    Toe angle (total): 0 degrees, 10' +- 5'
    Camber: 0 degrees, 46' +- 30'
    Caster @ 10 degrees: 9 degrees, 35' +- 30'
    Caster @ 20 degrees: 7 degrees, 50' +- 30'

    Rear:
    Toe angle (total): 0 degrees, 30' +- 6'
    Camber: -1 degree, 45' +- 10'
    Max allowable camber deviation between sides: 0 degrees +- 3'

    If my calculations are correct, these would then translate to:

    Front:
    total toe: 0.08° to 0.25°
    camber: 0.27° to 1.27°
    caster @ 10°: 9.08° to 10.08°
    caster @ 20°: 7.3° to 8.3°

    Rear:
    total toe: 0.4° to 0.6°
    camber: -1.92° to -1.58°
    max allowable camber dev: -0.05° to 0.05°
    Last edited by ¶Pho€nix; 05-29-2002 at 03:44 PM.
    BRACEYOURSELF
    It's gonna be a hell of a ride...

  5. #5
    Join Date
    Apr 2001
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    I think you goofed on the rear camber calc - it should be something like 1.58 to 1.92 degrees of negative camber.

    Anyway, like I said, I wouldn't pay too much attention to these ranges. Why don't you post your actual readings, and let's see what they're like...

    Jim

  6. #6
    Join Date
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    Split-up after "Door to Door" album was launched
    Yeah, I did notice a mistake with the rear camber as soon as I posted it.

    Here are my numbers:


    Fronts:
    Camber: -0.7°
    Caster: 6.8°
    Toe: 0.09°
    Cross Camber: -0.2°
    Cross Caster: 0.0°
    Total Toe: 0.17°

    Rears:
    Camber: -1.8°
    Toe: 0.24°
    Total Toe: 0.46°
    Thrust Angle: 0.01°
    BRACEYOURSELF
    It's gonna be a hell of a ride...

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