Funny tread wear/front end issues?

I'm seeing some funny tread wear on my 30 inch MTR's. The suspension is stock with exception of RS9000 shocks, and JKS LCA's, so I know those bushings are ok. The truck has 86k on it. All the ball joints up front have been greased. Nothing apears loose. What I'm seeing is on the outter tread block, the front of the block is taller than the rear of the block, assuming traveling in the forward direction. It is pretty consistent all the way around the tire. The last time I had issues with a straight axle and tires, I want to say I had inconsistent block wear, meaning every other one was lower than the previous. I wound up rebuilding with new kingpins etc. I'm wondering if this is a sign of Ball joint wear? or is my alignment off? It was aligned in the past 6 months. This has been going on long enough that it is apparent on the rear tire also (recent rotation) It appears most prominent on the passenger side.
Thanks for any input!

So you're saying that you have "sawtooth" type wear? Like the forward or rear of every outer block is sharper on one side or another, but all blocks are worn on the same edge? Rub your hand around the circumference of the tire on the outer blocks, should be sharp one direction and dull the other.

If this is the case, this is a classic toe-in problem (toed in too far, tires pointed toward eachother). Get an alignment. I worked in the tire industry for 6 years.

Jaredatriot:

DeadEyeJ said:

So you're saying that you have "sawtooth" type wear? Like the forward or rear of every outer block is sharper on one side or another, but all blocks are worn on the same edge? Rub your hand around the circumference of the tire on the outer blocks, should be sharp one direction and dull the other.

If this is the case, this is a classic toe-in problem (toed in too far, tires pointed toward eachother). Get an alignment. I worked in the tire industry for 6 years.

Jaredatriot:

Click to expand...

That pretty much describes it. That is irritating. It was aligned not long ago, but with some forthought, I purchased the LIFETIME alignment :laugh3: figureing I would get more than my money's worth out of it!
Thanks!

After the alignment, make them show you the manufacturer's specs for your XJ's alignment. Then make them show you a printout of your before/after specs. Then when you get it home, double check the tightness of all the bolts loosened to align it, pretty much everything on your steering linkage. I've seen more than a couple "freshly aligned" vehicles show terrible tire wear due to misalignment.

Jaredatriot:

Also, you should rotate the tires frequently, 5k miles or so. Of course I don't do it, thats why my tires look like crap!