Kubota Rear Inner Wheels Cracked

[vermontdane]

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?

 

[WinterDeere]

Green wins again!

j/k... serious bummer. Would it appear that the stud failed first, and then the increased stresses on the remaining holes caused the cracking?

 

[vermontdane]

No, the right had failed before without damage to the studs.

Re "Green wins again", I lived in VT/NH area and talking to both the Kubota dealer and the JD dealers.
The JD dealer was a complete jerk acting like I was doing him a favor. Since both made in Japan, went with the Kubota.
I would appreciate no starking snips when replying in the future.

 

[Thomas]

I believe Kubota M 4800 had the same problem and some owners had 1/4" plate steel cut holes drill and weld to rim for fix.

 

[LouNY]

Any thoughts about welding up the cracks, chamfering the holes and getting some lug nuts with the tapered seats.

 

[vermontdane]

I am definitely chamfering all the sharp edges before installing the new inner hubs. With inflation, now $325 apiece.

 

[LD1]

Hard to tell in the pic but are you sure the steel is cracked? Looks like just paint to me.

IF it were mine, I'd plate and weld no big deal.

 

[Hay Dude]

Beginning to wonder if those kubota wheels (or others) were ever designed for the extra stresses put on them from being filled with fluids.
Try some cast rims or wheel weights if you can swing the cost.

I also experienced sheared lugs on previous Kubotas I owned.

 

[LD1]

Beginning to wonder if those kubota wheels (or others) were ever designed for the extra stresses put on them from being filled with fluids.
Try some cast rims or wheel weights if you can swing the cost.

Filled tires dont effect the stress on the rim beyond what added traction there is. And if they werent designed to be filled with fluid, they wouldnt come with two-piece air/liquid valve stems made for loading them.

 

[WinterDeere]

No, the right had failed before without damage to the studs.

Re "Green wins again", I lived in VT/NH area and talking to both the Kubota dealer and the JD dealers.
The JD dealer was a complete jerk acting like I was doing him a favor. Since both made in Japan, went with the Kubota.
I would appreciate no starking snips when replying in the future.

Sorry you're so sensitive, or didn't see my "j/k", as in "just kidding". Either way, it was a joke. I don't think Deere is better than Kubota, both are fine machines.

But since you brought it up, you are not correct about both being made in Japan. My Deere was made in Moline Illinois, according to the PIN tag and all accompanying paperwork. Not that anything is wrong with being made in Japan, my 1980's Deere was a Yanmar, and a great tractor that was still running fine at age 33 years when I sold it.

Back to your issue though... While chamfering may help reduce stress localization a little, doesn't this look like a materials issue? Wondering if the wrong steel was substituted in production (i.e. was this a machine built during pandemic supply issues?), or if work-hardening from stamping is just causing an unacceptable brittleness.

 

[nyone]

I had a b8200 and the front wheels cracked like this. I just welded the cracks and put many more hours on it.

 

[5030]

I believe Titan made the wheels for Kubota. I agree with Hay Dude, cast center wheels are the way to go. Both mine came with cast centers and with the cast centers, the lug nuts are actually shouldered with a short cylindrical piece that indexes on the hole on the cast center. Never had issue one with either of mine. My fronts are still stamped steel but the mounting holes are chamfered and the lug nuts have tapered shoulders.

Nice thing about cast centers is no ballast liquid needed. The centers weigh about 400 pounds each.

I do check the prevailing torque on the fronts infrequently. Just like automotive wheels, they can back off.

Kubota wheels index on the raised hubs but when mounting you still need to have the wheels off the ground and wiggle them a bit to insure they seat on the wheel studs properly.

Far as JD goes, they mount the same way as Kubota.

 

[5030]

My Deere was made in Moline Illinois,

No, it was assembled in Moline, Illinois from parts sourced worldwide, so you are incorrect as well.

 

[plastikosmd]

Seems like a material issue

Weld and grind or replace and hope I guess

 

[WinterDeere]

No, it was assembled in Moline, Illinois from parts sourced worldwide, so you are incorrect as well.

True, but then we'd have to also question Kubota's "made in Japan", as both are assembled in one place from components sourced worldwide. Put otherwise, if I make dinner in my kitchen from ingredients grown in another state, I still call it home cooking.

Not a big deal either way, both are good machines. Sorry if my attempt at humor was misinterpreted.

 

[5030]

Cannot comment on that as I don't cook.

 

[Hay Dude]

Filled tires dont effect the stress on the rim beyond what added traction there is. And if they werent designed to be filled with fluid, they wouldnt come with two-piece air/liquid valve stems made for loading them.

I’m not gonna argue with you, but the long term stress of filled tires versus air filled tires is greater. Everything is carrying more load.
What I am thinking is Kubota may have under speced the steel in the rims, even unwittingly.
I have seen those cracks on many a Kubota.

Just spec cast rims and be done with all the filled tire nonsense and mess and extra wear (in my opinion).

 

[nyone]

It's a tractor not a race car so I wouldnt hesitate to weld the cracks for a second. If they continue to come back I would either weld thick washers over the holes or get a flange cut with the correct bolt pattern.

 

[Smokeydog]

Think I would have more confidence in welding a extra support plate to the original disk than a new replacement disk. Now those cast centers sound nice.

Kubota doesn’t recommend liquid ballast with a backhoe. They don’t say why. Even recommend ballast for 3pt hitch equipment but don’t tell you to remove the ballast to connect to a backhoe. Kubota kunfusion.

Hill county almost all tractors have liquid ballast. My Kubota TLBs have liquid ballast.

 

[mike peyerl]

I have 2 Kubota l3130 tractors and have cracked the rims on the one that I run tire chains on but not the one without tire chains