Caster Angle Adjustment Question

If I increase my caster angle by +4 degrees will this throw my wheel toe out of an acceptable range?

I just had an alignment today at Les Schwab. They claimed that they could only adjust the wheel toe due to liability. Making the adjustments to caster using my adjustable upper control arms is left to me. My wheel toe is currently aligned correctly and in range. My caster is currently at +1.6 degrees and should be within +5 to +9 degrees.

Thanks!

try to find a 4x4 shop in your area and they can adjust it for you. but if you adjust the caster by yourself its easy to check your toe angle http://go.jeep-xj.info/HowtoAlignment.htm after you adjust it drive in reverse for a few feet then im drive for a few feet to make sure your toe adjustment is correct

Is toe significantly effected if caster is adjusted positively by four degrees?

You will not affect your toe settings, by changing caster settings with your control arms; provided you make the control arms adjustments equally.

The toe will definitely change, the knuckles are setup for factory angles, so rotating the axle (caster) causes the preset camber to also change, which in turn causes the front and back of the tires to change gap.

Anyways, be careful with the caster tweaks. If you are lifted then the caster needs to be set for pinion angle FIRST and caster second... if you take caster back to stock then the pinion angle will be all wrong and you'll get vibes and/or eat u-joints in the front driveshaft. You can try increasing the caster a little bit at a time until vibes show up but give preference to the driveline angle. In my case I got around 3.5 degrees caster.

To set toe, use a tape measure to mark equal distant from the ground to a common point on the front and rear of each front tire, roughly equal with the center of the hub (eg, 14 inches high, or whatever is close and consistent for front and rear of each tire). Then use a tape measure to find distance between outside tread front and rear. Set the front to within +1/8" of the rear and you are done

I thought it would change. How much will the toe change by if it is set to factory standards with a 4 degree change in caster? ehall, how much lift do you have on the front of your rig?

Ehall, is technically correct. Toe will change, but probably only a negligable amount. By specs from the FSM, preferred camber is -0.25 degrees. Acceptable Range is -0.75 to +0.5 degrees.

But in reality for the amount of caster adjustment you'd be changing, I personally wouldn't be too concerned about the resulting change in toe. It's a XJ after all, meant to take off road abuse. Not a Formula 1 car. Also, a good smack to a curb, rock, ledge or pot hole; will throw off any alignment settings to some degree.

Keep in mind too that the preferred toe per the FSM is 0 degrees. Range is -0.10 to 0.25 degrees. So you've some room there too.

If you want to get technical, the aligment by tape measure technique is only as good as your measurement reference points, sag in the tape measure tape each time you measure, the amount of slop at the hook end of the tape measure, ambient air temperature, etc. I bet you'll get different measured variations each time you take a measurement by tape measure, trying to achieve your 1/8" goal. That's where the accuracy of lazer alignment plates from an alignment machine, can be more accurate than a tape measure.

In light of your recent alignment; if you are worried about tires wearing unevenly, just rotate them on a regular basis to achieve as even wear as possible....

Surfing around Tom Wood's sight, I came across this Multi Double Cardon.
This may work for keeping the original Castor / Pinion angle while also yielding
a smooth running drive line.
http://www.4xshaft.com/multiCV.html
Pricey though at $454.
I haven't heard anyone mention angled knuckle ball joints.
I've seen them around with anywhere from 1-4 deg.

Thanks! Wow, that is an insane driveline. lol

I just got a set of these from Amazon:

Pretty much foolproof! They even come with two identical tape measures. Less than the cost of one alignment.

heyhar said:

I just got a set of these from Amazon:

Pretty much foolproof! They even come with two identical tape measures. Less than the cost of one alignment.

Click to expand...

Do you have a link to those? I tried looking around on amazon but was unsuccessful.

Google "toe plates".

Perfect, thanks Hubs.

The trick i use to center my axle and do an alignment is by using a string tied to the rear wheels. You pull it strait forward and you will be able to see if you have too much toe in, toe out or if the front axle isnt centered.

Thats a good idea as well.

Im having some DW issues and I believe its in the aligment. Everything else up front is new. Need to set my toe to the positive side and check castor.

Another DIY method for measuring is to use a matching pair of old wheels, without any tires mounted on them. The lip of the wheel gives a nice consistent edge to measure from/to without any variations caused by the rubber of the tires. Just did mine last night with a couple of my old take-offs.

RadioShackSpecial said:

Im having some DW issues and I believe its in the aligment. Everything else up front is new. Need to set my toe to the positive side and check castor.

Click to expand...

Factory wants, IIRC, 0 to 1/8'' toe in, reason being that drag will push back out to zero. Any variation may cause the front end to want to 'hunt', and if the axle is hunting, but the body is not, you got some DW going. Just make sure the trackbar is as good as it should be.
A few slightly worn parts may equal a badly worn part. I got my '92 to settle down by replacing all the 'upgrades' with new stock stuff. Bushings, control arms, fancy track bar. I guess suspension engineers really do know their stuff!

The DW comes from the Drivers side. I can feel the drivers wheel/tire start to wobble when hitting bumps and when that side dips. On the rebound it starts to wobble. Only had it go into full on DW when I was driving on a really bad road, looked like IED's went off every ten feet.

There is a clunk from the drivers side when hitting bumps or gaps in the road surface. Only thing I have not touched is ball joints but I have to check for play before I dive into a ball joint swap.

I have four inches of lift up front from the RE 3.5" coils. The lowers are fixed length so I will be replacing them with adjustable pieces so I can dial in the castor.

The only other thing I can think of is too much back spacing on my tire/wheel setup. 15x8 wheels with 4" BS and 31" tire.

Am I on the right track here?

There are those who (and I tend to agree) think that any lift over the factory Up Country should be accompanied with some sort of revised control arms. As you lift the car, the top of the axle tends to move toward the back, before the bottom, leading to an increase in caster. Think of a shopping cart with wobbly front wheels, and you can envision DW caused by too much caster. All of this geometry stuff is why I have resisted lifting what brings home the paycheck.

As she sits right now, the top of the pumpkin is farther forward then the bottom. Which I think is negative castor. I need to be close to 5.5* of positive castor. So I need to push the bottom forward to get a better castor angle. That how I understand it. Sound right?