# Get Out And Explore! > Tech Section >  Rear Thrust Angle off question

## mjm2167

I just had an alignment done wanted to get an opinion on a fix for my thrust angle.
Im not sure of the math to tell exactly whats off in inches vs. degrees and to which side.
I do not have adjustable control arms yet, An have not checked bushings as of yet.

I know my rear trackbar is pushing the axle about a 1/4"+ to the driver side. Using
my redneck measurements... 

If i were to center this better, can any one tell me how this would affect the Thrust Angle? 

Or is this number actually referring to a combination of horizontal measurement and centering 
meaning my axle is **** eyed and not centered to boot? Meaning i have a little more of an issue?
Time to get adjustable control arms?

How bad is the Degree in inches? 

Thanks!
Mark

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## FSHJNKY

https://www.knowyourparts.com/techni...-thrust-angle/

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## FSHJNKY

https://www.freeasestudyguides.com/thrust-angle.html

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## Rubicon

It is an angle, thus not measured in inches.

This is showing you the rear wheels are pointing to the left and the steering wheel needs to be turned to the right slightly to compensate.

A correct length panhard bar, relocating bracket, and/or a caster bolt kit will be needed to correct. Or just drive it, as I would, because it is not a big deal.

The bigger concern, is it indicates that your front axle is bending. Common on JK's with bigger tires. Could get eccentric upper ball joint to compensate the camber. Or just drive it, since this is not really that bad either. Though a gusset & sleeve kit probably should be done to help prevent it from getting any worse, and the other side from starting ;)

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## mjm2167

> https://www.freeasestudyguides.com/thrust-angle.html


Thanks guys... this is what i was trying to figure out. An i'll get remeasured after wards. Am i wrong or over thinking this?

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## Rubicon

> Thanks guys... this is what i was trying to figure out. An i'll get remeasured after wards. Am i wrong or over thinking this?


Maybe I am wrong, though I did work at TFT, just not an alignment tech, but I thought I still understood the methodology. What you wrote(weight) should help the axle being offset sideways that 1/4" you stated. However it should not change the thrust ANGLE, as that is an ANGLE, as in measured in degrees, not inches ;)

This is how I read/see it, but someone please let me know if I am incorrect.

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## FreakinJeep

I'm pretty sure that thrust angle is not how much off centerline your rear axle is, rather the direction it's pointing. 

Being off centerline WOULD make it point slightly to the right or left based on the movement of the control arms, but I would think it would take a lot of side to side movement before you'd get angles changing.

I adjusted thrust angle with my adjustable control arms on the last axle swap I did. Not the track bar.

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## mjm2167

Thanks! there on my Christmas list... now for which ones. Ha-Ha

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## mjm2167

I have been looking at Metalcloaks, everyone seems to love them and no complaints with the bushings and add more flex. I am also looking at Synergy's adjustable arms while still on the rig which is worth the extra $$ to me. Im not a big fan of taking off and adjusting again. They have almost as much flex as the MC's. 

Anyone use the Synergy's? pro's and con's?

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## mjm2167

okay another question... seems like i fix one thing and have 2 more issues.

I upgraded to Synergy Control arms to fix my thrust angel, I figured while i'm at I'll adjust pinion angle and push the axle back a hair to get a little more clearance so i'm not rubbing plastic near / on the inner rear tire well seam.

I used this for my adjustments...

Rear Lower Control Arms = 20 7/16"
Rear Upper Control Arms = 18 7/16"

My issue now is my rear sway bar links are hitting my trackbar mount, and it introduced a bit of coil roll.

My plan is to get a 10deg coil adjustment plate, and bring the upper arms in 1/2" and use adjustable links. An depending on where this puts me, I was also think of moving the rear swaybar back a 1/2" which will require drilling and tapping a couple holes.

Has any one else ever run into this and what did you wind up doing. I still have factory CV drive shafts so I'm still trying to be cautious of pinion angle.

Thanks!
Mark

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## Rubicon

> okay another question... seems like i fix one thing and have 2 more issues.
> 
> I upgraded to Synergy Control arms to fix my thrust angel, I figured while i'm at I'll adjust pinion angle and push the axle back a hair to get a little more clearance so i'm not rubbing plastic near / on the inner rear tire well seam.
> 
> I used this for my adjustments...
> 
> Rear Lower Control Arms = 20 7/16"
> Rear Upper Control Arms = 18 7/16"
> 
> ...


Hi Mark,

Not sure if it was for the rear of a JK, but I have seen offset sway-bar frame adapter mounts to cure contact issues. Might have been for a XJ?

And if you have CV style shafts still, then pinion angle is less of a concern, as long as the Rzeppa joint is not getting maxed out. Though if you can get the u-joint on the pinion side close to 0 degrees with a CV on the transfer end, that would be the desired setting.

Good luck!

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