Camber and castor specs for 67 CJ5

Hello,

I am currently in the process of narrowing a ford Dana 44 HD for the front of my CJ5 narrowtrack. I have settled on a WMS to WMS of 56 inches. I plan to run Humvee rims which should gime me a track width similar to stock. Can anyone tell me what I should set my knuckles at as far as castor ? I thinking about 5 degrees ?

Extreem

 

btt

 

I think that's about right. I have heard either 5 or 6 degress neg. castor is the trick. The Dodge Dana 44 I had narrowed was set to 6 degrees.

 

I kept thinking that too, when the builder was cutting down my axle; but then he took me back into the shop and showed me with an axle up on the stands what he was talking about and it all made perfect sense.

 

so im kinda lost wich way is negative ad postitive ,dumb? iknow but hey wile your talkling about it!,jared

 

DIctionary.com says:
cast‧er  /ˈkæstər, ˈkɑstər/
Pronunciation[kas-ter, kah-ster]
–noun
6. Automotive. the angle that the kingpin makes with the vertical. Automobiles are usually designed with the upper end of the kingpin inclined rearward (positive caster) for improved directional stability.

My jeep seems to have positive caster.

Kevin

 

That diagram is right. Negative caster would point your differential up toward your xfer case (on the front axle) and positive would point it toward the ground.

 

Positve caster, lower pivot forward of top pivot, like a bike fork. IMHO, camber should be as close to 0 as possible.

 

Mmm, well, yeah, sort off. If you changed nothing else, and twisted the axle to make caster more negative, the pinion angle would change toward the transfer case.

However, the caster is welded into the axle by rotating the knuckles wrt the expected plane of the spring pads. Both the pinion angle and the caster are fixed by their relative rotations, and their rotation wrt the spring mounting pad. If you change the plane of the spring pads with new springs or shackles, then all three change but stay the same wrt each other.

 

You raise an interesting point. One of my first questions to myself was why did the Ford F250 axle run almost zero castor ? I was thinking it may be chassis specific. Funny thing is, I did a SOA swap with the original Dana 27 as a mock up axle and had no idea about Castor at the time (15 yrs ago) I ended up with about 3 degrees of negative castor but no "Death Wobble" when running 35's up to 60 MPH a few weeks ago. Maybe I should just set the pinion angle, run 1 to 2 degrees of positive castor, and bring it in with shims if I experience any issues ?

Thanks for all the input....

Extreem

 

I would go for more than 1 or 2 degrees. What is a real problem and causes "wheel shimmy" is worn parts which change your caster angle, or when one side is positive and the other is negative. If you are close to +1 then a worn or damaged part may put it at zero or -1 on one side and the other will still be positive. Then you will have a shimmy, especially when you hit the brakes.

The more positve the caster angle the more stable and straight your vehicle will travel. The wheels will want to stay straight, as stated above, look at bike forks, or a dragster. Negative caster will make the steering easier, but the trade off is the vehicle will wander more.