Random wear on my steer tires.

That will check the primary valving but not the secondary valving which would cause the tire wear like that. A bad primary valve causes more bounce than anything.

 

Shocks and shackle bushings is my guess. How often to you check and grease bushings? New shocks my not help much if the shackle bushings are too loose or too tight. We use a jack to get the weight off the shackles, but not all of it, leave the tire on the ground. Then you can use a pry bar between the spring and hanger to check for clearance. There shouldn't be excessive play, but it should have a little. Once the pins are checked, we jack the tire off the ground and grease. If they don't take grease easily, something is wrong and we pull the pins to check.

Is is very important for the shackle to move freely. When you hit a bump, the spring flattens out and gets longer. If the shackle cannot allow the spring to extend easily, spring motion is jerky and the tire takes a harder hit.

Do you balance steers or run equal in them? Any shimmy? A shimmy from unbalance could cause some wear like like, but not usually isolated to the center unless it's over inflated.

 

I am having the same issue with mine so please keep us updated...

 

had the same thing 80000 miles tires shot, put on balance masters and used wheel center sleeves last set of tires 210000 mile have well over 100000 on this set no more cupping. also i run Michelin xada3 22.5 tall

 

I'm curious . Have you checked tread depth across the tires ? Are they thinner in the middle ? I run 78-79,000 when I'm loaded , at 95 lbs. cold , and mine are showing signs of being over-inflated. Thinking of dropping them to 90 PSI.

 

Where's a good place to jack up, to check the shackle bushings? Do you check both sides at same time or one side?

 

I have a new 579 on order, was gonna spec a Flex-Air rear suspension. Salesman talked me into a low air leaf instead, showed me a bulletin from the Pete factory saying that if you only ran loaded one way, and had many empty return trips that the flex air caused unusual front tire wear. No one seems to have an answer as to why. I don't know if that's your problem or not, or even if you're running a Flex-Air. Just thought it was interesting info and that it might save you some $$$ trying to chase a problem that's designed into the vehicle that may not have a fix other than changing out the rear suspension.

 

I have seen that exact wear, especially the center river wear from a bad / damaged tie-rod bushing before.

http://www.google.com/url?sa=t&rct=...uRc_6rWuUIBB-oHDdOsufMw&bvm=bv.49478099,d.eWU


Of corse check shackles, kingpins, bearings etc. first, ensure components are good. Jack it up and spin tires to ensure they are not wobbly from rims, bad mounting, eggshaped. but also,...

Has the front end u-bolts ever been removed? Its common for a shop to get the caster adjustment plates backwards or height wrong. Do a basic camber and caster check on both sides regaurdless. Caster should be 4-6 degrees + in reference to the frame rails when sitting on level ground. Camber should be +1-2 degrees max from one side to the other at the top. You do not need any fancy, crappy laser that is not very acurate on caster/camber, for a caster/camber check, especially if the waer is setting in that fast. All you need for caster/camber alignment checks is a decent digital saw-blade leveler (twenty five bucks from Amazon.com). Zero it out on the frame rail then stick it to the front side of the king pin housings on each side. It should read 4-6 degrees foward offset from 90 degrees. Foward offset means the bottom of the kingpin housing should be closer to the front of the truck than the top. Some dealers / alignment shops will offset one side to the other to compensate for crown in the road, so if the driver side is +5-6 and the passenger is +4 then this is still ok. Camber is a simple matter of zeroing the blade leveler out on one of the front cross members in the center (the one across the bottom of radiator is nice and strait), then setting aganst the outside of each rim with the steering facing straight foward. It should be only 1-2 degrees max difference from one side to the other and will also show how much truck is leaning. This will reveal very quickly a bent spindle, etc. Again, no need for fancy inacurate laser.

this is the one I use...has solved many alignment issues for me.
Wixey WR300 Digital Angle Gauge


this post is likely to piss off a few mechanics,..lol,...Rawze