Ideal caster?

Any agreement here on what ideal caster is? The sheet from the alignment machine says 2-4 degrees... but I recall that a little more is better.

 

5-7* would be my gut feeling.

 

Yup, 5-7* is what I've found ideal, especially with oversize tires or if your roads are rutted.

 

The machine says I have 0.1 degree now. There's no secret over- or under-estimating the shims for this, is there? I'm thinking a 6 degree shim would be the right choice to put it right - and most likely to measure in that ideal range.

 

Sounds about right Tim. If you're in the 5-7 degree range you should be fine

 

Yup, 6 degrees is perfect for mine!

 

I recently put in 4 degree shims on my 72 and t while it really improved the darting I feel it could use a few more degrees. I'm running 7.00 15 radials that are about 31 inches tall and they like to walk around a bit. I think I'm going to order a set of 6 degree shims and feel that this should be about right. BTW I had it in for an alignment check (before shims) and they said the castor was "about right" which is supposed to be 3 degrees by the book. They didn't give me print out because they cleared the machine. Nice.

 

You really don't want more than 7* positive caster or you can have slow speed hard steering, accelerated tire wear in turns. And in some cases can cause high speed instability.

 

I put 6 deg. shims in mine which helped the tracking tremendously, although the slow speed sharp turning requires greater effort. Just something to get used to.

 

Time to find another alignment shop if they can't tell you what it was. ALL modern alignment machines have printers on them and most have the ability to save the results under the customers name.... The alignment machine I just got rid of which was almost 20 years old even had that ability.

 

x3 for 6 degree great ride!!!

 

Such as ...

 

I've noticed lately from a number of experiences that alignment shops just don't know what to do with these older rigs. They focus mainly on camber and toe, but pay little attention to caster. I had a buddy that had a newer TJ that had serious bump steer and death wobble. He took it in, they said it was fine. He brought it over, it was 0 degrees...

Ive always done backyard alignments though. Its not perfect, but I know its right.

 

Since the thread was about the magic caster angle I hesitated to elaborate on my poor alignment experience. Yeah I was Pi$$ED, $49.95 for a toe in adjustment! Bigjohn hit it on the head, they had no idea what they were working on so they just messed with the toe in. I paid in cash and figured they would hold the print out hostage until I paid up. I paid and asked for the printout and the mumbled some crap and said they cleared the machine. I said do it again and give me the printout but they said they were closed and if I wanted they would call the cops. I figured that nothing would be gained by police intervention so I backed off. Lesson here is ask if they know how to "align" a solid front axle and make it clear you want a printout. I figured a print out was SOP so didn't want to insult them by asking. Live and learn.

 

There's a big difference between operating an alignment machine and doing what it tells you and actually knowing how to align vehicles. Someone who truly knows how to align vehicles looks at the specs but also looks at the actual numbers and compares that to what the vehicle is doing and makes adjustments accordingly. Lots of times I've had to align vehicles "out of proper specs" to get them to drive right and not wear tires. Especially on modified vehicles....