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Thread: Bump steer

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  1. #1
    Join Date
    Jan 2010
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    Your best action is to not lower the car so much that bumpsteer is an issue.
    Houston Region
    STU Nissan 240SX
    EProd RX7

  2. #2
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    Jul 2004
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    Raleigh NC
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    Bingo. That and follow the old adage "Any suspension will work as long as you don't let it".

  3. #3
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    Nov 2007
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    South of Chicago, near Indiana.
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    Just asking a question here: Couldn't you consider the steering system on a rack-n-pinion steering system part of the suspension? The tie rod is a link in the suspension and it's connected to the rack which is connected to the K member with bushings. And since suspension bushings are free in IT then couldn't you take it to the point where you can use offset bushing to try to correct bump steer? Dicuss.

    I owned and raced a Fox Mustang and know the issues of bump steer. I didn't race it in IT so I was able to correct it using the more common heim joints in lew of tie rod ends method rather then offset rack bushings.
    1988 ITA Scriocco 16V #80
    MCSCC member since 1988

  4. #4
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    I suspect that is a bit of a tortured interpretation. The GCR defines suspension bushing as:

    Suspension Bushing – A hollow cylindrical mounting component which
    acts as a bearing, allowing constrained motion, between a suspension
    component and attachment point.

    The IT bushing language is:

    Bushing material, including that used to mount a suspension
    subframe to the chassis, is unrestricted. This includes
    the use of spherical bearings, so long as no suspension
    component is modified to facilitate their installation. Retention
    of spherical bearings by use of tack welds is allowed,
    as long as the welds serve no other purpose.

    And that language is under "Suspension Mounting Points". Steering is not specifically mentioned or called out, but, steering as defined in the GCR is a bit weak and doesn't specifically cite the rack.

  5. #5
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    There was something going around about that thought process a few months ago. basically, as Ron said, it's a tortured interpretation and I would expect some feedback about it.
    Houston Region
    STU Nissan 240SX
    EProd RX7

  6. #6
    Join Date
    Jun 2005
    Location
    Kansas
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    Quote Originally Posted by jimbbski View Post
    Just asking a question here: Couldn't you consider the steering system on a rack-n-pinion steering system part of the suspension? The tie rod is a link in the suspension and it's connected to the rack which is connected to the K member with bushings....
    I don't know how you came to the conclusion that the tie rod is a link in the suspension, but I disagree. You can leave the tie rod laying on the shop floor and still have fully functional "suspension", as defined in the GCR technical glossary - "A mechanical system of components controlling vertical motion and connecting the axle housing and wheels to the chassis of a car."

    IMO, the tie rod does not meet the first of two requirements in that definition.
    Gary Learned
    MiDiv
    Volvo 142E
    http://www.youtube.com/user/denrael

  7. #7
    Join Date
    Feb 2001
    Location
    Tampa Fla
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    430

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    yes there is a kit out there to correct the issue of bump steering in a lowered mustang. it looks like a spacer between the tie rod end and the steering knuckle.

  8. #8
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    Dec 2001
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    raleigh, nc, usa
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    Quote Originally Posted by manny View Post
    yes there is a kit out there to correct the issue of bump steering in a lowered mustang. it looks like a spacer between the tie rod end and the steering knuckle.
    And is illegal.
    NC Region
    1980 ITS Triumph TR8

  9. #9
    Join Date
    Sep 2008
    Location
    FL.
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    Optimize the rack mount bushings and Subframe bushings. Not all steering arms are straight . Maybe yours are bent? Not all tie rods are the same , maybe you have short studs? Maybe there are longer stud tie rods. 5/8 fine thread I think.
    Read the rules as far as rack placement, tie rod ends, lower control arm bushings. Just moving the lower point a little will help. "Tolerance stack" is what you want to do. Move all of these points the legal maximum amount.
    Lower is faster, deal with the bump/ The mustangs can be pretty bad. I fix a bunch of the street rods that are way off, and raced a bunch of circle burners..
    IMHO. MM
    Mike Ogren , FWDracingguide.com, 352.4288.983 ,http://www.ogren-engineering.com/

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