MikeOK

Thanks you guys for helping me out. You saved me some cash and I won’t be so disappointedin myself for not doing it myself.

The strange thing about this is, is that it still drives straight down the road. It takes a bump at speed or the rough air when passing a semi to cause it to swerve. The first thing I did to it was adjust the toe a little and that improved it quite a bit. I’m just hoping that’s all I bent, but looking at it it’s not bent much, about 1/4“ laying a straight edge against it. Oh well, either way I’m going to get closer to a bulletproof rig.

MikeOK

Another thing. While at the dealer I looked under a ‘16 and ‘17 to make some comparisons and they both had single steering stabilizers, mine has dual. Is it a difference in the model years or is it because I have the sahara package?

resharp001

Honestly, I think a lot of people are out there in this very situation, and they think it feels fine cuz they don't really know much different. I can speak from experience in a cheap arse 4" Pro Comp lift with no caster correction. I thought it was just fine. I knew no different.....UNTIL I started building this crap the right way. Once I felt what proper caster felt like it was enlightening. Like a "damn....I get it now" moment. At least that is how I can see how his comment an our "how the hell can that be driving perfect" together can be figured out.

In regards to the SS Mike....No, that is anot a stock thing with your Sahara. Either the dealer or the shop put that on....and really no clue why. Double steering stabilizer is just double whaaaaa???? Really, all you need is the cheapest thing ever. That also might explain why you think it drives ok as the stabilizer is soaking up some of the reactions. If your caster is right, and everything else is good.....you can drive all day long without the SS and not even notice it is there. So many people try to use a SS or a double SS to COVER UP symptoms of not having a proper set up. It's like putting a band aid on a damn artery cut if you ask me.

MikeOK

I can just compare it to stock, and my old TJ.

resharp001

caster from the factory is 4.2*. If you are getting an actual 3" lift out of the coils, I'd bet you're around 3.3* caster. Sinec Rednroll didn't throw his fav vid in here, ima do it. I CANNOT condone the use of the "R" word in this video AT ALL, and it bothers me, BUT, this is the most simplified example of caster and the effects.

https://www.youtube.com/watch?v=t76BVhtBMnE&t=183s edit - LOL, changed the link. don't think anyone wanted a pimped out Dodge Magnum ride on CL. Gotta find a new vehicle for the spousal unit and told her I was buying a low rider with blingy 20's

MikeOK

I called the shop and asked how they set my caster and they said if it doesn’t have cam bolts then they didn’t change it. I’ve done a lot of research on this and found it’s easy to set my toe, but after doing a lot of reading I’m just more confused about setting caster. I’m going to change these CA’s and set my toe, but should I set my caster myself or would you recommend taking it to a shop? If it drives as good as it did before why do I even need to check it?

Edit: I called Teraflex and they said 1 in 100 JK’s need caster correction with my lift.

resharp001

I'd suggest saving the money on labor, install them yourself. You might have to adjust the lengths a couple times to get the caster close to where you want it. Then run it to an alignment machine, get the read out, and go home and tweak a rotation or two on the arms to dial it in.

I use this picture a lot -


Your axle's caster and pinion have a fixed relationship. The C on the end of your axle tubes have a 6* tilt built in. When your pinio is at 0*, your caster is at 6*. Now, from the factory the caster is 4.2*.....meaning the pinion is angled up 1.8*. Make sense so far? Well, as you lift the jeep, the side effect is that you raise the pinion (increase the angle) (cuz the TC got lifted and the axle did not....so you increased the angle from diff to TC). Well, you need a way to lower that pinion back down. For every 1* that the pinion gets raised, the caster is decreased by that same 1*....cuz the relationship is tied together. So, you can use geo brackets, or adjustable control arms to lower the pinion (raise the caster) again. If just using lower arms like you plan to do, you'll increase the length of the arm......which will push the entire axle forward.....and as a result will lower the pinion.....and the effect will be an increase in caster.

Ideally you have a full set of arms, using the lowers to position the front axle, and the uppers to tilt the diff.

So, you can get a cheap $11 angle finder, and put it on your pinion flange (demonstrated by the red box in the pic above). Assuming your floor is flat, read the angle your pinion is at. If the pinion shows a 1* angle, then your caster is 5*. If it shows 2*, your caster is 4*. If it shows 3*, your caster is 3*....and so on and so forth. I'd guess you are closer to 3* - 3.3* range currently. Mind you, cheap angle finder is not perfect, but generally will get you close.....then go get an alignment read out, come home and tweak if necessary.


When you look at the picture above, and you see the bicycle example in the video, does it start to make sense? the front fork of the bike is the same as the C on the end of your axle tubes.

MikeOK

Okay, thanks again. I found a good article on it and your post matches it. I’m downloading an angle finder app on my iPhone. So if I understand you correctly, I check the angle on my front u-joint and this gets me my pinion angle, and all I have to do is do the math to get my caster?

resharp001

If you have the factory pinion flange there it's easiest. If you've replaced the pinion yoke you might have to find a better spot to measure from. Even then, it's obviously not going to be accurate as a computer, but as mentioned before, most alignment places wont adjust those arms for you without charging a decent bit. You can get it close yourself, go get it scanned, and then go home and tweak yourself as necessary.

But yes, you're going to measure your pinion angle, and then simply calculate the caster. assuming your pinion is pointed up a bit (a positive angle), which it will be, simply take 6* - whatever you measure your pinion angle to be = caster*. You'll most likely want to be in the 4* - 5* caster range. Recall that factory is 4.2*. If you have a double cardan driveshaft.....if you run too much caster you can start getting driveshaft vibes. Also though....since you are only using lower arms.....you'll be balancing not wanting to push your axle too far foward.

It's probably starting to make a little more sense now why you use the lower arms to position the axle, and then the uppers to raise/lower the pinion angle (and by nature set the caster) now right?

MikeOK

Yep, got it. I was making it harder than it is. There’s a 49 page thread I’m reading over on wranglerforum too.