Handling difference with mud tire and 18”

Discussion in 'Stock Suspension + Bolt On Kits' started by east302, May 2, 2021.

  1. df2x4

    df2x4 Domestics only.

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    I guess I should clarify a little bit. Over-boosted steering due to a failed or unplugged column sensor won't completely prevent the wheel from returning to center, but it can slow the process to a point where it feels "off" especially at certain speeds. For example making a slow 90 degree turn at 10-15MPH you may have to help it back to center a little.
     
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  2. Nad_Yvalhosert

    Nad_Yvalhosert I'm Awesome

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    The caster angle is responsible for return to center. The higher positive caster, the better highway manners, and better returablilty.
    Less caster, more wander, easy steering.
    But definitely check for binding ball joints and tie rods.
     
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  3. Pinger

    Pinger I'm Awesome

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    You star!
    I've just been searching for that. Beer goes to you - cheers!
     
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  4. boy&hisdogs

    boy&hisdogs I'm Awesome

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    Do the new wheels and tires stick out much farther than stock? That would make the steering feel a little sluggish.

    But fix the things that are for-sure broken first, like the steering components and alignment.
     
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  5. Pinger

    Pinger I'm Awesome

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    Not just castor but trail, KPI and offset also affect self centering. As overall wheel/tyre diameter impacts on most of those factors, it does too. Front anti roll (sway) bar can also.
     
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  6. east302

    east302 I'm Awesome

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    Yes, I should’ve mentioned that. I don’t know what width the rims are (they aren’t GM rims) but the tires stick out probably 1-1.5” more than stock. I don’t like them at all.

    Nothing is obviously binding when watching from underneath and everything was torqued to spec.
     
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  7. Supercharged111

    Supercharged111 I'm Awesome

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    What's trail? KPI is pretty well fixed. I suspect it greatly leads caster in these rigs.
     
  8. Pinger

    Pinger I'm Awesome

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    To visualise trail - look at the (virtual) king pin and see the castor slope. Now move the entire 'pin' forwards. That's trail - like a supermarket trolley wheel has.

    KPI is fixed - true. But I think the longer 'footprint' of a larger diameter tyre magnifies its effect.

    There's a mix of forces acting to self centre steering and their effects vary depending on what the truck is doing. Some are dependant on the grip at the road surface, others the weight on the wheels (eg, less with aerodynamic lift at speed).
     
  9. Supercharged111

    Supercharged111 I'm Awesome

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    The way you describe trail sounds exactly like caster?
     
  10. Pinger

    Pinger I'm Awesome

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    At the ground it pretty much is. But by using trail the same effect can (theoretically) be had with a vertical king pin axis - if that is desirable!
    I think it's use is in combination with caster to lessen king pin angle (in side elevation view) as caster creates effects due to weight. If it is used at all these days, it is in very small amounts.
     

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