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D60 alignment, caster, return to center ...

Mastiff

Mastiff

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The poor return to center with my K5 is bothering me. It's not terrible, but I'd really like it to be better. And I swear it returns better from the left than it does from the right. I can't think of what could cause that though. This is a newly rebuilt D60 with crossover, 4-5" lift, ORD springs, new steering shaft and gear (basically all new from steering wheel down) FWIW.

I have 4* shims on the D60. Is that too much? Are most guys running shims at all? Also, I wonder if I anyone has their front end professionally aligned (all they can do is toe rght)? I did the best job I could at home trying to get just a little bit of toe in. IIRC I went for 0.5" closer tire to tire in front compared to back, using a common chalk line. I know this is not going to be perfect though.

Anyway, looking for ideas. My old stock CUCV has good return to center, so I know a D60 can do it.
 
With respect to the shims, what matters most is your final caster angle. What is your caster angle? Caster is a big factor in return to center, it can also cause DW.
 
nvrenuf said:
With respect to the shims, what matters most is your final caster angle. What is your caster angle? Caster is a big factor in return to center, it can also cause DW.
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7 degrees give or take 0.5. Visually it looks like it's pointing up more than the CUCV, but I haven't measured that one.
 
*I think* the caster spec is 8-11 degrees.
 
Mastiff said:
And I swear it returns better from the left than it does from the right.
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IIRC, you're supposed to double-shim D60's on the pumpkin side, one shim between the spring and the axle and the other between the spring and the spring plate. This keeps the studs absolutely perpendicular to the spring pack and plate. Umm, for example, see the fine print on

http://www.wfoconcepts.com/pr/8-0-Degree-Steel-Axle-Shim/3229

Without the second shim, it might be that the one side is ever so slightly misaligned from the other which could lead to the above.

Or not. What do I know :D

-- A
 
I do have the double shim going on. So that's not the problem.
 
1/2" is too much toe in...3/16" is plenty and should help your return to center.
 
I'm just wondering where you get these toe in numbers from when setting it yourself. If someone with 35" tires sets it at 3/16 (measured at circumference of the tire) and someone else uses that same toe in when they have 31" tires, then the person with the smaller tires will have more toe in. In order to get a better standard wouldn't it be better to measure toe in at a common reference point like at the rotors with the wheels off?
 
rampage said:
I'm just wondering where you get these toe in numbers from when setting it yourself. If someone with 35" tires sets it at 3/16 (measured at circumference of the tire) and someone else uses that same toe in when they have 31" tires, then the person with the smaller tires will have more toe in. In order to get a better standard wouldn't it be better to measure toe in at a common reference point like at the rotors with the wheels off?
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If you set toe at the rotor, then actual toe at the tire will depend on how big the tire is.

If you set toe at the outside of the tire, it will be consistent. I've always used 1/8" with good results.
 
I always assumed an official toe spec would be in degrees, in which case tire diameter would be an important consideration when setting it this way. Is that not true? How the heck do you measure to 1/8 anyway?
 
tape measure daaa :whistle:

and wfo fine print shows good spec for dana 60 caster . your way past that .

from there page : Caster Angle: Caster angle is something that is very important on front axle geometry. On a fully off-road vehicle that does not see speeds over 15mph, you can get away with poor caster angle. If you are working on anything else, please read this!

Caster Angle is the angle that the knuckles sit at, compared to the ground. If you shim your front pinion up or down, the caster angle with change with the shims. The less caster angle you have, the more the vehicle will dart around on the highway. The more caster you have, the straighter the vehicle will drive. A drag race car will tend to have up to 18 degrees of caster.

The first thing that everybody does when they lift their 4x4, is install shims to point the differential up at the transfer case. Even though this does fix some driveline angle issues, it usually does more damage with the steering geometry than it is worth.

On a Dana 44, we suggest 5 degrees of caster angle. On a Dana 60, we suggest 3 degrees of caster angle. This means that the knuckles will be leaning back at the above angles. It you had high-steer arms on the knuckles, the arms would be pointing up at the front bumper at 5 degrees.

Even on a fully off-road buggy, at no point should you ever go past 0 degrees and point the knuckles down at the ground in front! If you need to make your driveline work at a steep angle, check the u-joint or yoke sections for high angle u-joints and high angle yokes.
 
I have a similar setup and don't have any shims. Return to center is pretty normal. Mine has ~10 degrees of caster.
 
bp71k5 said:
I have a similar setup and don't have any shims. Return to center is pretty normal. Mine has ~10 degrees of caster.
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I bet my CUCV is about there. Everything I find surfing indicates that 7 should be plenty though. I'm not sure what to think.

How critical is toe to the return to center and general driveability? The range of numbers here is barely bigger than my measurement tolerance. All I did was spin the tires to make a chalk line and try to measure with a tape measure. Maybe I'm doing it wrong, but it doesn't seem like a very exacting process.
 
Mastiff said:
I bet my CUCV is about there. Everything I find surfing indicates that 7 should be plenty though. I'm not sure what to think.

How critical is toe to the return to center and general driveability? The range of numbers here is barely bigger than my measurement tolerance. All I did was spin the tires to make a chalk line and try to measure with a tape measure. Maybe I'm doing it wrong, but it doesn't seem like a very exacting process.
Click to expand...

I just took a string and used that to measure between the tire sidewalls near the tie rod and then took another measurement 180 degrees away in the back. Last I checked it was 1/4". Could your steering box adjustment nut be too tight ( he one with the allen head screw?
 
Mastiff said:
I always assumed an official toe spec would be in degrees, in which case tire diameter would be an important consideration when setting it this way. Is that not true? How the heck do you measure to 1/8 anyway?
Click to expand...

This chart is relatively close to what my GM manual says.
http://coloradok5.com/forums/showthread.php?t=280577

My manual says caster is 8* nominal and toe in is 0.15* +/-.07*.
In order to translate the degrees toe in into a difference between the front and rear tire tread measurements we can do some simple trigonometry which I could bore and confuse everyone with or just use this online calculator (both ways came up with the same numbers):
http://robrobinette.com/ConvertToeDegreesToInches.htm

Also, did you check the caster on both sides to make sure they were the same. I know they should be the same but they could be slightly off.
 
Caster angle affects return to center and toe adjustment will just wear out tires if not close to spec of 1/8" toe-in. I believe my caster is set right around 8-9* and mine returns to center just like it was factory.
 
4X4HIGH said:
Caster angle affects return to center and toe adjustment will just wear out tires if not close to spec of 1/8" toe-in. I believe my caster is set right around 8-9* and mine returns to center just like it was factory.
Click to expand...

Do you have shims?
 
Can't remember what my caster is but I cut my front ZeroRates to have 5* in them.

The toe might not help but 1/2" is too much, gotta fix that anyway.

My favorite method is using two 4' levels aka straight edges, tape measure, and helper. (no helper, strap 4' level to tire) Holding each level against sidewall horizontally, measure at the end of the level in front and behind the tire. So basically it's like you have a 48" tire. This is super repeatable, fool proof. I run 3/16" toe in, but since my tierod is bent, it could be 1/4" by now. Just finished driving home tonight from beating on it, 70-80 no problem.

(I have hydro assist = no return to center, not much help)
 
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