What pinion angles are u guys setting the 79 Dana 60 axles to? My tires are wearing uneven. Its wearing to outside of the tire the insides show no wear at all.
Soa with shackle reversal, 1.5 Re springs, 42 iroks.

pinion angle should have nothing to do with tire wear. Check your front end alignment. Oh and my pinion angle is set so it is pointed directly at the transfercase so the driveline is straight.

Pinion angle has everything to do with caster if you haven't cut your tubes. It is a common mistake to attempt to set up the front axle as you would the rear - pinion aimed at the transfer case yoke. On most uncut fronts this setup will cause a negative caster condition causing outside tire wear mostly noticable on pavement. Offroad rig may get away with it. Set up the caster at approx. six degrees positive caster. Pinion angle will be what it will be and must be dealt with in a different way.

Pinion angle has everything to do with caster if you haven't cut your tubes. It is a common mistake to attempt to set up the front axle as you would the rear - pinion aimed at the transfer case yoke. On most uncut fronts this setup will cause a negative caster condition causing outside tire wear mostly noticable on pavement. Offroad rig may get away with it. Set up the caster at approx. six degrees positive caster. Pinion angle will be what it will be and must be dealt with in a different way.

caster is not a tire wearing angle...only camber....caster will determin if your wheel returns to center on its own or not

It is not a wear angle driving straight down the road, but while making 90 degree turns on pavement, it causes the outside edge of the tire to grind throught the turn. Properly set-up caster is designed to assist in returning the tires effortlessly to center when completing a turn.

Six degrees positive caster, proper air inflation on pavement - Presto!

Could have too much toe in? It's easy enough to check.

It is not a wear angle driving straight down the road, but while making 90 degree turns on pavement, it causes the outside edge of the tire to grind throught the turn. Properly set-up caster is designed to assist in returning the tires effortlessly to center when completing a turn.

Six degrees positive caster, proper air inflation on pavement - Presto!

x2. just wanted to back you up. so Blue1TonYJ gets a answer.

don't mean to be a dick but these pics are the basics of wheel alignment and if his outside is wearing he has too much positive camber. and heres the definitions of caster and camber (copy and pasted by yours truly:flipoff2:)

Camber


When camber specifications are determined during the design stage, a number of factors are taken into account. The engineers account for the fact that wheel alignment specifications used by alignment technicians are for a vehicle that is not moving. On many vehicles, camber changes with different road speeds. This is because aerodynamic forces cause a change in riding height from the height of a vehicle at rest. Because of this, riding height should be checked and problems corrected before setting camber. Camber specs are set so that when a vehicle is at highway speed, the camber is at the optimal setting for minimum tire wear.
For many years the trend has been to set the camber from zero to slightly positive to offset vehicle loading, however the current trend is to slightly negative settings to increase vehicle stability and improve handling.

Caster


Positive caster improves straight line tracking because the caster line (the line drawn through the steering pivot when viewed from the side) intersects the ground ahead of the contact patch of the tire. Just like a shopping cart caster, the wheel is forced behind the pivot allowing the vehicle to track in a straight line.
If this is the case, then why did most cars have negative caster specs prior to 1975 ? There are a couple of reasons for this. In those days, people were looking for cars that steered as light as a feather, and cars back then were not equipped with radial tires. Non-radial tires had a tendency to distort at highway speed so that the contact patch moved back past the centerline of the tire (Picture a cartoon car speeding along, the tires are generally drawn as egg-shaped). The contact patch generally moves behind the caster line causing, in effect, a positive caster. This is why, when you put radial tires on this type of car, the car wanders from side to side and no longer tracks straight. To correct this condition, re-adjust the caster to positive and the car should steer like a new car.


and heres the link to the website i got this stuff from it goes into decent detail. http://www.familycar.com/alignment.htm

also i would like to say that too much pinion angle over stock will result in positive camber. if you have leaf springs grind off the perches and try and lower it closer to stock. from what i have read +4 - +6 degrees pinion angle over stock is about the max you would want to run before cutting and rotating your inner c's. thats not an exact number but thats what i mostly see. also it is possible to be toe in on top of the camber issue. thus causing fast tire wear. you might be better off taking it to a mideas or something and get them to set it up on the alignment machines to get it dialed in perfect, that is unless you own your own.

i have looked all over i have a 91 wrangler with 6in lift and 37" tires i need the right pinion angle so i can drive it with out melting the rear u joints

Point the rear end directly at the t-case. most likley you will have to get a CV shaft.

The front end has a ton of positive camber built in. Some camber shims and you should be set.

Maybe I was just lucky but I ground out both 'C's on my scout Dana 44, that I had recently installed on my CJ-7, rotated the pinion up to point straight at the T-Case then rotated my 'C's to a negative 6`caster and then rewelded. My steering no longer follows every rut in the pavement and though mine is mainly a trail rig it is truley fun to drive on the highway. I think I had 8-10 hours total (and I take a lot of beer breaks). It's just not that hard to do and all you need is a decent angle finder for setting the caster.:)

Do not point your front up toward the transfer case, you can't.. That will set your caster down into the negative. Bad stuff.
Castor is the steering plane, the knuckles pivot together and this angle which they pivot must be level with the ground. Rotating the pinion UP, rotates the knuckles DOWN.. Which makes the axle turn down... Into the ground, instead of level with the ground.

An easy way to make sure you are in the safe zone, is to look at the surface where the diff cover mounts. This flat surface should not be pointing down. It should be 90 degrees to the ground. You can measure the castor angle precisely by pulling the hub, spindle & axle shaft and place a dial type angle finder inside the inner knuckle. You should be 2-8 degrees in the positive to be safe.

Tire wear is usually caused by poor camber, which can be due to a bad ball joint, or worn out hub. Or even your tire could be unbalanced or the wheel bent. Also, another huge tire eater is if your TOE is too far in or out.

Or simply... Offroad large tires often times wear like crap anyway. Even uneven air pressure can cause them to wear unevenly.

i have looked all over i have a 91 wrangler with 6in lift and 37" tires i need the right pinion angle so i can drive it with out melting the rear u joints


Looked all over for what?
Were talking about the front axle!

You can point your rear axle pinion up toward the sky,
That doesn't matter. You need a rear drive shaft with a double cardan CV joint! Get one out of the front of a Cherokee, make sure the CV works smooth. You'll also need to get a slip yoke with a new yoke that will work with a CV, they are diff than normal U join yokes.

This is Hardcore Tech?

[QUOTE Six degrees positive caster, proper air inflation on pavement - Presto![/QUOTE]

If I park my jeep on a level ground can I put an angle finder on the high steer arm to measure for the 6 degrees caster?

How u determine the proper air inflation for pavement? When I air my 42 iroks to 30 psi only middle of the tire has contact with the pavement. Right now I have them down to 12psi to get more tire contact with the pavement for even wear is that the proper way?

?

Yes thats the easiest way to look at what your caster is.
I would guess 12 is a little low bit somewhere in the 20-25 lb would get you closer

when I air my tires to 20 to 25psi only the middle of the tires has contact with the road when I air them to 12 to 15 I get more tire contact is that wht ur aiming for?

Then I guess you should air back down to 12-15. normally the best way to check is with chalk or something on the tire and see when you get complete coverage

Negative castor will wear the ouside of the tire because when you TURN the tire turns down into the ground... and rolls under. Thus wearing the outer shoulder over time.

squirt some agua on level cement & drive tru it & git out & look for an even tred print. center only means too much air...let some out untill a full print shows.

Negative castor will wear the ouside of the tire because when you TURN the tire turns down into the ground... and rolls under. Thus wearing the outer shoulder over time.
yup

The whole battle of pinion angle vs. caster was easly won by pinion,, with the caster set correctly, my ds was binding so bad it was snaping the grease port off the ujoint and makeing a hellasious noise, so the coil buckets were cut off and the axle tilted foward, yes to negative caster- it turns the same as negative caster(like a yocht) due to the 40's, no more angle issuse-solved.