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Rear toe change with load

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Old Aug 14, 2018, 07:21 PM
  #16  
kaj
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And none of it is the "wave" from the camera? I know sometimes my GoPro does some weird wave/shifting stuff, depending on where I mount the camera. My phone does it, too.
Old Aug 15, 2018, 01:40 AM
  #17  
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I would first measure the toe curve trough the whole travel... it might be that you are just seeing some unlinear characteristics at the end of the curve, due the relative low ride height you are running..
Old Aug 15, 2018, 09:35 AM
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Originally Posted by Dallas J
Have you tried slowing the video and just watching the lip? Certainly looks like its moving quite a bit to me but will get a better angle after I get these bushings replaced.
At the unloaded state, the tire is blocking the view of the leading edge of the wheel. As the tire flexes, it covers and uncovers the leading edge, making it look like it moves. Look a the rear lip of the wheel that is not obstructed by the tire at that camera angle. That stays in the same spot on my screen the entire time. ... at least, that's the way I am seeing it.
Old Aug 15, 2018, 09:39 AM
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Originally Posted by psushoe
At the unloaded state, the tire is blocking the view of the leading edge of the wheel. As the tire flexes, it covers and uncovers the leading edge, making it look like it moves. Look a the rear lip of the wheel that is not obstructed by the tire at that camera angle. That stays in the same spot on my screen the entire time. ... at least, that's the way I am seeing it.
I agree, as well. After thinking about it & watching the Vid again, that tire is certainly moving laterally, quite a bit (as it should)
Old Aug 15, 2018, 10:10 AM
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Was mostly working on machining parts last night but did zip-tie my level to the wheel with the shock removed to see if I could get a quick view of the bump steer. Unfortunately my level doesn't have a dot, but a line so it was hard to get a plot of the arc. Though just following a point, it didn't appear to be that drastic. Will try to refine my hacked way of checking though.

What I did see was that I could grab the spokes of the wheel and flex things left right enough that it was obviously moving the laser mark several millimeters. This was with a ~50ft-lb couple, with a larger force its going to move much more. Nothing is loose, but Im definitely moving it.

Tonight I'll move the strap up on the wheel and pull harder and see what it is that I'm flexing.

I can certainly agree the video may look worse than it is with the tire flexing, though I feel like I'm seeing at least some wheel movement as well. Will report
Old Aug 15, 2018, 12:21 PM
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Shouldnt be all that difficult to rig up a dial indicator, on an arm, & place the probe on the wheel (checking the runout)

Run the EvO through a few hard corners & check the dial indicator movement (imagine rigging a GoPro to view it)

Something like this as an example

Last edited by MinusPrevious; Aug 15, 2018 at 02:11 PM.
Old Aug 17, 2018, 07:45 AM
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i did this a few years ago. as i recall i was surprised by the apparent toe-in during full compression. wish i could find the video
Old Aug 17, 2018, 08:14 AM
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I have a ton of droop, so when I jack my car up I can see the wheels toeing out a ton. I'm assuming the rear bumpsteer bushing should help to some degree with the toe in and out conditions.
Old Aug 17, 2018, 10:51 AM
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looks like mostly tire flex to me. There is some bump steer but not as much as it looks in the video.
Old Aug 17, 2018, 11:05 AM
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So quick update, I put an indicator on the front edge of the wheel and pull on it with my strap about 1/3rd of the way up at the front edge. Putting some pretty good load with the small 1" ratchet strap I was able to get up to 2mm of deflection. Not a huge amount, but it is ~ 1/16" with at best guess a few hundred pound load applied a bit unrealistically to normal loads.

Mostly just trying to see what kind of deflection I was actually getting. I may repeat with the strap on the bottom again and see if its any better or worst at the bottom and at the front center of the wheel. Im swapping bushings in the upper and trailing arm this weekend and will check if its improved.
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Old Aug 17, 2018, 03:41 PM
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Cool finding Dallas.
We all look forward to your experience this weekend.
Glad its toe-in, so more consistent handling.
Old Aug 19, 2018, 03:11 PM
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Originally Posted by Dallas J
Im swapping bushings in the upper and trailing arm this weekend and will check if its improved.
I did the whole rear yesterday and the upper sucked to do. Had to burn out the front bushing on the upper and took a little bit of time to figure out how to remove the rear bolt on the upper from the drivers side.

Old Aug 19, 2018, 04:24 PM
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Originally Posted by CaptainSquirts
I did the whole rear yesterday and the upper sucked to do. Had to burn out the front bushing on the upper and took a little bit of time to figure out how to remove the rear bolt on the upper from the drivers side.
Got mine done also, its always a pain swapping bushings. Have the wheels off till I swap over rubber to the sticker tires for nats. And that rear bolt was a pain, looking forward to never dealing with that damn bolt again... though now I get to pull it each year for fresh lubing.
Old Aug 19, 2018, 04:55 PM
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It sucked not knowing how to do it but it wasn't that bad once I figured it out. I just unscrewed the two screws from the gas cap, unbolt the fuel filler shield and I was able to pull it down a little to have room to pull the bolt out.
Old Aug 19, 2018, 05:19 PM
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Originally Posted by CaptainSquirts
It sucked not knowing how to do it but it wasn't that bad once I figured it out. I just unscrewed the two screws from the gas cap, unbolt the fuel filler shield and I was able to pull it down a little to have room to pull the bolt out.
Ha. Now I remember doing this. 😂
I was like, "why was it so bad?"
Yup...now I remember LOL.



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