Kubota Rear Inner Wheels Cracked

[BravoXray]

Is this why they went from stud pilot to hub pilot wheels on trucks?

I believe that was one reason, the Budd type fastening system was notorious for breaking wheels and the nonsense of using 10 inner and 10 outer nuts on each dual wheel, and left and right handed threaded fasteners on their respective sides on some vehicles, though after the 70s most all were right hand thread, at least on the Petes I owned.
The Pilot type was used in Europe long before it was adopted here, and has greatly extended the fatigue life of wheels and halved the fastener count on each wheel.
The washer type nuts on Pilot wheels exert only a clamping force on the wheels, while the Budd nuts were ball shaped and thus exerted a lot of stretching force on the area around the nuts, as was shown by frequent cracking around the holes.

 

[SPYDERLK]

I have 2007 L3240HST which I always have a backhoe and front loader attached.
The dealer set up the tractor with fluid in rear tires and chains.

For the 2nd time, my rear inner wheels have developed cracks around the lug nuts towards the inner hub.
I check the torque often and always correct.
760 hours on the tractor.

A couple observations.
1. Kubota does not chamfer the sharp edges on the inner wheels. Sharp Edges are stress risers.
2. The wheel lugs are not self centering. The clearance on the bolts and studs will allow slippage.
One of the studs has sheared off. I have seen this on an M series tractor as well.

Are there others with this issue?

I have Kub Ls in that size range and have not had any issues, but no B/H. I recall though a prior conversation here where a cracking problem presented. There was some talk of lug torques and they were surprisingly low for 16mm bolts. I went out then and removed one of mine and slapped it back down to "stall" with the impact wrench on low. Then with a torque wrench I found the torque applied was 250ftlb. That is an overtorque, but no damage. I recommend that you remove those lock washers and replace them with Grade 8 flatwashers available at TSC. I would tighten the lugs to at least 200ftlb.

 

[Smokeydog]

I have 2007 L3240HST which I always have a backhoe and front loader attached.
The dealer set up the tractor with fluid in rear tires and chains.

For the 2nd time, my rear inner wheels have developed cracks around the lug nuts towards the inner hub.
I check the torque often and always correct.
760 hours on the tractor.

A couple observations.
1. Kubota does not chamfer the sharp edges on the inner wheels. Sharp Edges are stress risers.
2. The wheel lugs are not self centering. The clearance on the bolts and studs will allow slippage.
One of the studs has sheared off. I have seen this on an M series tractor as well.

Are there others with this issue?

Curious, what is the thickness of the disk at the hub?