Help with alignment specs please

lueser

New member
So I just got the truck wheel alignment after lift. It drives straight but when hitting bumps seems like wheels shake and wobble. Compared mines with others and is different. 3 inch lift on 285/75/17 and spc uca. Please give me your inputs
 

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So I just got the truck wheel alignment after lift. It drives straight but when hitting bumps seems like wheels shake and wobble. Compared mines with others and is different. 3 inch lift on 285/75/17 and spc uca. Please give me your inputs

Your caster is significantly different from left to right, 2.7 and 3.5 respectively. I'm not sure what the effect of that would be. I had a shop tell me recently that it was that way to allow for the peak in the center of the road.
You should also be able to get your caster a bit higher, closer to 4 would be better.

I'm no expert though.

An a separate note, how's the rubbing with the 285/75? I run them but never did before I had my bumper and BMC.
 
Your caster is significantly different from left to right, 2.7 and 3.5 respectively. I'm not sure what the effect of that would be. I had a shop tell me recently that it was that way to allow for the peak in the center of the road.
You should also be able to get your caster a bit higher, closer to 4 would be better.

I'm no expert though.

An a separate note, how's the rubbing with the 285/75? I run them but never did before I had my bumper and BMC.

I hate when shops due the "bare min." its literally on the edge of being acceptable , at least per the shops sheet and instead of trying to make it any better *Stop, jobs done, within range* - granted I think more of this has to do with the way shops treat/pay the techs vs. the techs themselves - if my families well being depends on me getting alignments done in 15min well I am going to do all I can to do so within the allowable range. Optimization is extra :)

OP I am not sure that the cross caster would cause what you are feeling but its where I would start, see if the shop is willing to nudge the 2.7 up.
 
I'm no alignment expert ether but your SAI and Included Angle Turning Angle Diff looks way out of spec. Not even close to the specified range.
 
I have the same UCA w/3 inch lift with caster at 4.1 on each side. Drives like a dream even after 10K miles of on road and off road trips.

Me? I'd take it to another shop.
 
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I think you need to take it back where it was aligned and have it adjusted on their dime. Tell them to aim for 4 degrees castor and see what you get back. I'm not sure if the right way is for castor to be balanced, or staggered to compensate for road crowning, but I'd love to know as I've got an alignment coming up on my 2 IFS trucks.

Let us know your final specs and how it drives, good luck!
 
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I think you need to take it back where it was aligned and have it adjusted on their dime. Tell them to aim for 4 degrees castor and see what you get back. I'm not sure if the right way is for castor to be balanced, or staggered to compensate for road crowning, but I'd love to know as I've got an alignment coming up on my 2 IFS trucks.

Let us know your final specs and how it drives, good luck!

This^^^. They may need to change presets on the SPC arms to get enough adjustment from the lower arm cams. Caster is staggered to deal with road crowns. Your car will pull to the side with the lower amount of positive caster (i.e. a road crown causes drifting to the right, so left side caster is lower to counteract that drift).
 
This^^^. They may need to change presets on the SPC arms to get enough adjustment from the lower arm cams. Caster is staggered to deal with road crowns. Your car will pull to the side with the lower amount of positive caster (i.e. a road crown causes drifting to the right, so left side caster is lower to counteract that drift).
Thanks guys taking her in monday
 
Thank you sir
You're welcome, but how are yours oriented? I have seen situations in the past where SAI and other secondary angles were wonky and had terrible driving characteristics because of a failed installation.

My LRs drove great with 6 degrees of caster for a few thousand miles before the crappy ball joints wore out. I replaced them with TC's that I have been running for about 175 thousand miles and no alignment adjustments needed.
 

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