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Thread: big differences in roll centre...

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    User fantapants's Avatar
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    Default big differences in roll centre...

    curious about something guys.

    my understanding of bump steer was DIFFERENCE in the arc of the of the lca and the steering arm. as they ravel through their suspension arc, one travels on x radius and the other on y radius and the resulting change i toe is bump steer??

    with that in mind, what would be te likely results of a BIG difference between these arcs?

    i have s13, and i am aware of the problems associated etc etc etc. i was looking at the max steering knuckles as one of the issues i have had is the steering rack forming a solid line and tightening up. These provide 2 inch of drop on the knuckle, but i can only get a max of 35 mm rca ball joint for the lca.

    i have also seen the same setup used without any rca for the lca??? what sort of effect would this have on overall handling?

    so what say you oh masters of grip??

    cheers

    pat
    RIP Carly - a smile to light the world.
    06/07/2011

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    Veteran driftke70's Avatar
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    Default

    angle grinder
    wheelfriends.wordpress.com

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    yeah besides cutting the tip off my finger what would i do to it?
    RIP Carly - a smile to light the world.
    06/07/2011

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    Default

    dont know about angle grinder. pretty sure you can remedy youre little problem with a spanner. lol.

    jokes aside. have you had a good look at the relationship between the lca and tie rod, the way it is now?

    i have noticed these sorts of nissan alignment products dont seem to be marketed as a system.

    i cant really give an impression as to why, as i havent had a look at the s13 stuff when lowered, not in an s13 anyway.

    possibly, when lowered, and more so, when a lot of caster is wound in when lowered, the steering knuckle arm angle is changed enough that a miss match in these products "heights" is required to return the alignment of the 2 arms (lca, and tie rod) to closer to their correct relationship.

    should be noted, that even for ae86s, where a simple spacer (rca) can be used to manipulate both pivot points at once, there are still available after market tie rod ends for fine tuning of the relationship between the 2 arms.

    ive personally never got that far into it.



    thats them.

    having the s13 stuff in an ae86 though, kinda puts you out there on your own somewhat. kinda uncharted territory. you might need to make friends with Adam. not an easy man to make friends with. lol. but no im sure he could give you some better insight.

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    Default

    i read that a couple of times and im not exactly sure what you are asking.

    Yes, any difference in the steering arm arc to the lca will create toe in/out on bump which is the bump steer you talk about.

    Correcting it is a little tricky, and usually a case of trial and error, especially when dealing with a mish mash of componentry.

    Correcting this may involve a number of approaches

    moving the steering rack foward/backward, up/down
    modifying the lca pivot point
    adjusting the static height of the steering arm/lca

    The indicator of what is going on is to build a simple gauge to show what the toe is doing through the suspension range. It is simply a hinged bit of wood (say 2 pieces 40 x 40cm) with 2 screws that point to reference areas eg the outer lip of the rim. with the front springs removed raise/lower the car in increments to identify the toe during bump/droop.

    when you have done this you canbegin to rectify the problem

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    User fantapants's Avatar
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    yeah i sometimes get lost in my own awesomeness... i mean badly worded questions

    my main queery is how gnarly an effect would a static height difference of about 2 inchs?
    and yea i would rather eat arse than grovel to adam lol. ill figure it out myself befor that!

    THANKS FOR THE INPUT GUYS.
    RIP Carly - a smile to light the world.
    06/07/2011

  7. #7
    carbonae86
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    fanta what is it with you and the male ass

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    User fantapants's Avatar
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    meh male donkeys female donkeys??? all donkeys to me


    yeah i know about that page and have looked into most of the stuff on there, howvere most dont have anywhere near level suspension arm arcs when applied to the max setup.

    i have spoken to the guys at max and i think it is something along the lines of what dimitri suggested, that the changed angle etc etc etc and a change in the positioning angle of the extension works in a less than clear fashion, but the guys do say it works

    ps do i know you?
    RIP Carly - a smile to light the world.
    06/07/2011

  9. #9
    carbonae86
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    would they have suggested sticking the car on a bumpsteer guage first ?

    ps i dont know any persons that are into paddlin

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    already been suggested abpove and done....


    and your missing out
    RIP Carly - a smile to light the world.
    06/07/2011

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