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Thread: toe setting; convert mm into degree/minutes

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    Registered User austrian type-R's Avatar
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    toe setting; convert mm into degree/minutes

    hi!

    Well, that is giving me some headache. After searching around for about 3 hours I am more confused than before.

    My tire-dealer got a new allignment machine which only tells the shit in degree/minutes (60 minutes = 1 degree)

    On the old machine from the same shop I had adjusted like that:
    front toe -4mm
    rear toe: + 6,7mm

    Now whats that in degs/mins?


    this is how I had adjusted today, but I am not sure if this is correct:
    front toe: -52 minutes (-26 minutes each side)
    rear toe: + 1 degree and 33 minutes (+45 left and +48 right)

    whats this in mm about?

    PS: I used S2000 16inch datas, because NSX was not in the computer of the machine. I run 17inch (215/40) front and 18inch (255/35) rear. How much does that affect?

    thanks
    Last edited by austrian type-R; 07-17-2007 at 08:13.
    red 1991 NSX; 303hp
    turbo Integra type-R; 515hp

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    Registered User austrian type-R's Avatar
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    Re: toe setting; convert mm into degree/minutes

    Found this in the web:
    http://wiki.seloc.org/a/Geo_Setups

    Converting from mm to degrees:

    1. Multiply rim diameter in inches by 25.4 to get rim diameter in mm.
    2. Multiply the result by PI to get the circumference.
    3. Divide the result by 360 to get mm per degree.
    4. Divide the toe mm by the mm/degree result to get toe in decimal degrees


    okay, I did a little math with the steps above and my old toe settings:

    pi = 3.14159265


    17inch: 431,8mm
    1356,53
    3,767
    4mm/3,767
    1,06/2= 0,53 degree per side - thats about 32 minutes per side



    18inch: 457,2mm
    1436,33
    3,989
    6,7mm/3,989=1,679
    1,679/2=0,839 degree per side - thats about 50 minutes



    compare now old to new alignment:
    - 26 minutes NEW versus - 32 minutes OLD on front each side
    + 45/48 min NEW versus + 50 minutes OLD on rear each side.


    What do you think? ...should I go a little less aggressive, since the numbers are a bit off, cause of the Honda S2000 specs which was diald in on the allignment computer? ...or just compare to another car which has 17inch and 18inch from factory, so the numbers are correct in the computer of the machine?
    Last edited by austrian type-R; 07-17-2007 at 09:10.
    red 1991 NSX; 303hp
    turbo Integra type-R; 515hp

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    Re: toe setting; convert mm into degree/minutes

    mm of toe is tire diameter dependant. The toe corresponds to the distance in inches from which the rim diverges at its back compared to its front at the axis height.

    But the alignment machine often assume a fixed tire diameter (~28 inches). Which means, for the NSX that has a lower tire diameter, that the mm of toe given by one of this machine is a little bit bigger than the real toe applied by some %.

    If we take a toe angle of 0.1 (6' minutes) each side :

    NSX rear wheels are ~25 inches = 635 mm (depend on the tires).

    The way it diverges at the rear compared to the front is 635 mm x sin 0.1 = 1.11 mm.

    Calculated this way, which is tire size dependant :
    0.1 each = 0.06' each = 1.11 mm each -> 0.2 total = 0.12' total = 2.22 mm total

    If the alignment machine assume a 28 inch tire diameter (it doesn't take in account the exact tire diameter) :

    0.1 each = 0.06' each = 1.25 mm each -> 0.2 total = 0.12' total = 2.5 mm total

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    Registered User austrian type-R's Avatar
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    Re: toe setting; convert mm into degree/minutes

    hm, well, I understand nothing.

    Is this wrong?
    http://wiki.seloc.org/a/Geo_Setups

    ...is my setting comlpetely off? How many mm do I have now?
    red 1991 NSX; 303hp
    turbo Integra type-R; 515hp

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    Registered User austrian type-R's Avatar
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    Re: toe setting; convert mm into degree/minutes

    red 1991 NSX; 303hp
    turbo Integra type-R; 515hp

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    Re: toe setting; convert mm into degree/minutes

    Quote Originally Posted by austrian type-R View Post
    Right.

    This give the results I explained before.

    Enter 635 mm as tire diameter (~NSX's rear tires). Enter 0.1 (= 6 minutes = 006'). This corrspond to 1.11 mm.

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    Re: toe setting; convert mm into degree/minutes

    On the old machine from the same shop I had adjusted like that:
    front toe -4mm
    rear toe: + 6,7mm

    Now whats that in degs/mins?
    If the machine take in account the ~605 front /~635 mm rear tire diameter :
    Front : - 4mm total toe corresponds to -0.38 total toe (-023')
    Rear : +6.7 mm total toe corresponds to -0.60 total toe (-036')

    If the machine assumes a fixed say 28 inch tire diameter (712 mm) :
    Front : - 4mm total toe corresponds to -0.32 total toe (-019')
    Rear : +6.7 mm total toe corresponds to -0.54 total toe (-032')

    this is how I had adjusted today, but I am not sure if this is correct:
    front toe: -52 minutes (-26 minutes each side)
    rear toe: + 1 degree and 33 minutes (+45 left and +48 right)

    whats this in mm about?
    Front : ~10-11 mm total
    Rear : ~18-19 mm total

    which are crazy numbers.

    Do you have a alignment repport ?

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    Registered User austrian type-R's Avatar
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    Re: toe setting; convert mm into degree/minutes

    yes, it is an A4 sheet.

    I have called the shop and we do an realignment soon. I have told them also that someone should learn the machine better to switch into mm or do a manual input on the tire diameter. The tech guy from the alignment machine company is calling me back. )
    red 1991 NSX; 303hp
    turbo Integra type-R; 515hp

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    Registered User austrian type-R's Avatar
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    Re: toe setting; convert mm into degree/minutes

    Would this numbers be right if I would know if the machine reads the rim-diameter or the total diameter of the tire?


    this is per side
    FRONT: 11,4 minutes tirediameter 605mm
    REAR: 16 minutes tirediameter 635mm

    FRONT: 16 minutes rimdiameter 432mm
    REAR: 23 minutes rimdiameter 457mm
    red 1991 NSX; 303hp
    turbo Integra type-R; 515hp

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    Re: toe setting; convert mm into degree/minutes

    Quote Originally Posted by austrian type-R View Post
    Would this numbers be right if I would know if the machine reads the rim-diameter or the total diameter of the tire?


    this is per side
    FRONT: 11,4 minutes tirediameter 605mm
    REAR: 16 minutes tirediameter 635mm

    FRONT: 16 minutes rimdiameter 432mm
    REAR: 23 minutes rimdiameter 457mm
    You have to understand that whatever the rim diameter or the tire diameter you fit on the car, the toe angle in degrees or in minutes will be the same !

    If you put 205/40 R 15 tires front (545 mm diameter) and you have 11.4 minutes toe, toe in mm is 1.8 mm.

    Then you change your tires to 215/40 R 17. Your toe is still 11.4 minutes. But expressend in mm, toe is 2.01 mm.

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    Registered User austrian type-R's Avatar
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    Re: toe setting; convert mm into degree/minutes

    Quote Originally Posted by austrian type-R View Post

    this is per side
    FRONT: 16 minutes rimdiameter 432mm
    REAR: 23 minutes rimdiameter 457mm
    Today I was at the tire shop again and I made some pix of it + a comparison between mm and degree/minutes, cause we found out how to switch from degree to mm. I was also able to insert the correct rim diameter which is used by this machine and not the overall tire diameter. Some other people on other forums has told me also to use the rim diameter.


    with the wrong numbers before the readjustment; rear and front






    after the readjustment; rear and front

    it is 16 minutes per side front
    and 23 minutes per side rear
    I have the print outs here in mm and degree/minutes.





    The sensores of the machine


    red 1991 NSX; 303hp
    turbo Integra type-R; 515hp

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    Registered User mr_goat's Avatar
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    Re: toe setting; convert mm into degree/minutes

    Resurrecting a really old thread, sorry for that =)

    My alignment guy had a machine showing the toe in degrees, not mm. He said he would convert and it shouldn't be a problem. He gave me toe angles in the rear of 0,5 degrees per wheel, which, according to my my calculations, results in a total toe of 12 mm!! Not 3 mm, which was what I wanted.

    No wonder my brand new tires are flat from the middle and in after only 600 miles!!

    My front toe is -3 mm according to these calculations which is OK though.
    Veilside Maisty Fortune 1991 Acura NSX

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