Ask The Expert- JK Front Caster, front and rear pinion angle

#1
Hi, just installed MC 2.5” game changer Rocksport edition with 37x12.5” on my 2017 2dr Rubicon. Looking for confirmation of best setup
-front caster angle
-front pinion angle
-toe in
- rear pinion angle

Many Thanks
John
 

Brian

Jeep Fanatic
#2
Hi, just installed MC 2.5” game changer Rocksport edition with 37x12.5” on my 2017 2dr Rubicon. Looking for confirmation of best setup
-front caster angle
-front pinion angle
-toe in
- rear pinion angle

Many Thanks
John
Caster should be around 5 degrees and your front pinion angle will be determined by your caster setting. Toe in is set at about 1/8" for those size tires. Do you have a dual cardigan rear shaft?
 
#3
Caster should be around 5 degrees and your front pinion angle will be determined by your caster setting. Toe in is set at about 1/8" for those size tires. Do you have a dual cardigan rear shaft?
Brian is 100% on this. 4.5°-5.5° is where the JK's like to be. Front pinion will follow with this.
 
#4
Castor should be around 4° to 5°. Don't be afraid to run less than 5° if you get DS vibes although at 2.5" lift you should be fine, in an ideal world the pinion angle would be up 1° in front and dropped 1° to 2° in the rear. If you are particularly bothered about toe, do your research, some people will tell you to run close to zero others at 1/8" or more, you'll find a justification for both and everything in between, Personally, I just go anywhere in the factory spec which i think is 0.03° to 0.18° per side
 

Pthorpe84

Moderator
Staff member
#5
I’m frustrated with toe. I have done 1/8” toe in and at different speeds I will still get death wobble. Right now I can get it every once in a while at around 30 mph. This is with the new tie rod and balanced new tires. I’m hoping the new lift and drag link will cure some of this. I am also in the process of going redneck ram. Currently I am running no steering stabilizer...mainly because I keep smashing them.


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Brian

Jeep Fanatic
#6
I’m frustrated with toe. I have done 1/8” toe in and at different speeds I will still get death wobble. Right now I can get it every once in a while at around 30 mph. This is with the new tie rod and balanced new tires. I’m hoping the new lift and drag link will cure some of this. I am also in the process of going redneck ram. Currently I am running no steering stabilizer...mainly because I keep smashing them.


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How are your ball joints? May I also ask if you are measuring toe? If so, is it from the front of the tire? The larger the tire, the farther away from the axle and the less actual toe in you have.
 

Pthorpe84

Moderator
Staff member
#7
I measured and adjusted when i put in the tie rod. I am 1/8” toe in. Ball joints are till good. Checked them too. The issue definitely got better with new tie rod and tires. I am sure it the alignment next week should fix the issue. Fingers crossed


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#8
Are you sure you have Death Wobble ? do you have to come to a complete stop to get out of it ? What backspacing are you running and what Castor ? If you have a "Shimmy" thing going on that isn't DW and you KNOW all of the system components are good, you can try changing something, anything, Wheel offset, toe in, castor, tire pressures, many components make up the system.
 

Pthorpe84

Moderator
Staff member
#9
Yes it’s the death wobble. I do have to come to a dang near stop to make it go away. My wheels are 3.5”. The castor should be at stock height considering I was running the factory suspension. I just finished a game changer install and it’s at the alignment shop. So all SHOULD be good. We shall see. I know Jason at Rock Your 4X4 is one of the best there is. I have no doubts he will get it handled.

On a side note...I did find that I have a seal leak in the front passenger side axle. Really need to regear and do chromoly before Moab in May.


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