Trying to get to the bottom of this issue. Inside tires wearing on inside excessively and unevenly. Happening on two of my three booms. One has just been aligned with trunion rebuilt and kingpins in front done by Alsams trucks alignment. Doesn't seem to be a tire pressure issue. Will get the one back to alignment shop to get there opinion. Josam s has a school to train and manufactures and sells truck alignment equiptment.

Someone once told us if that's happening you excessive play in ur bearings, take the shaft out of axle and tighten up the big nut with a socket as tight as u can and than loosen back up an than finger tighten it again. We have found it does make difference .

Check your torque arms.   They are in between trunion and differentials. They look like dogbones. Check the bushing where they connect for pushed out rubber or broken.  Also hard to see but see if the shaft is bent.  Easiest way to tell is to grab and check for play. You should not be able to move them.

A local hauling company bought a boat load of Mack Dump Trucks a year ago.  They are getting about 15,000 miles out of the back tires.  The inside tires are wearing out faster then the outside ones.?

what brand of tires. We have foumd the chesaer the tires or the more mismatched the worse it all gets. Whats brand of truck is this on?

Sounds like a over weight on the tandoms to me .

sounds crazy but its the rear bushings .measure one tandom on the right than measure the left .center axle to center  of the rear see if there is a deferents in the two

Yes your trunion bushings can also cause inner tire wear.  Trunion bushings, leaf spring dampeners, and torque arms will allow for the rear axles to move around twisting.

we had the same problem with a unit, we found the axle housing was bent. We changed it problem fixed, you might have a mechanic look at it.

Old concrete, You speak the truth. Dont change the axle, Send it to A frame shop. They can make it straight if you tell them whats wrong. Most people dont understand this. As for what 79xlch said, Those trucks have been abused. A dump-bucket is some of the most abused equipment that man has ever built. A pump truck aint too far behind. If bearings are tight,,, Make her straight. Seen this in the past.

Pumpnfinish--  work 'em hard boy lol.   Been pretty busy past couple weeks. Not enough time for me to keep up repairs.  Fix 3 machines they break 2 more lol

I think of this every time that happens lmao