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Does Strut Excursion Cause Toe-In Error?

Discussion in 'Gen 3 Prius Main Forum' started by jimolson, Jul 5, 2024 at 4:20 PM.

  1. jimolson

    jimolson Member

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    I replaced an outer tie rod end on my 2010 and stared briefly at the vehicle's front suspension. It's amazing that fragile suspension members can deal with Indiana's spring pothole season.

    The centroid of the outer tie rod end necessarily moves on a constant radius from the inner tie rod when the car hits a pot hole or over a lump in the road. That fixed radius is determined by the length of the outer and inner tie rods plus any connecting link that exists between the two tie rods.

    But the position of the front wheel relative to the car's frame changes during potholes or road lumps.

    As the wheels move up and down relative to the frame, is front toe-in changing a bit as a consequence of the fixed radius asserted by the steering linkage? It seems to me that toe-in should change.

    Said differently, wheel bounce on rough pavement should cause change to the toe-in setting, and probably causes tire wear. Is this correct?
     
    #1 jimolson, Jul 5, 2024 at 4:20 PM
  2. Tombukt2

    Tombukt2 Senior Member

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    It's probably so negligible that it's almost not worth tracking or can't be tracked maybe
     
    #2 Tombukt2, Jul 5, 2024 at 6:53 PM
  3. Mendel Leisk

    Mendel Leisk Senior Member

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    Your descriptions seem very thorough, but nevertheless I’m lost. Photographs, sketches might help. I appreciate it is complicated.
     
    #3 Mendel Leisk, Jul 6, 2024 at 8:15 AM
  4. Leadfoot J. McCoalroller

    Leadfoot J. McCoalroller Senior Member

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    I haven't done a detailed study of Prius suspension, but in many similar car designs it is normal for toe-in to increase upon spring compression.

    This is generally desirable from a handling standpoint, and because the condition is temporary and brief it won't present any tire wear or efficiency loss worthy of action.
     
    #4 Leadfoot J. McCoalroller, Jul 6, 2024 at 8:30 AM
  5. Tombukt2

    Tombukt2 Senior Member

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    I think it flexes the alignment both on compression and extension when the car goes down and far up but like you say those are rare events so tire wear would be non-existent or minimal or not really measurable or worth the time to measure because it's so small. On race cars and things like that there's not a lot of suspension undulation because of the tight springs and all the other things set up on the car correctly things like that but the race car is not made to go to food Lion and take the kids to school it needs to have some sort of suspension that makes sense and doesn't beat everybody's kidneys to death You have no sponsors taking the kids to school no reason to be driving a race car and race trim with the kids to school then to the food Lion although some people do it
     
    #5 Tombukt2, Jul 6, 2024 at 8:49 AM
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