A little disappointed with Kubota

[SPYDERLK]

I agree with this theory.

For clarity though, Six isn't saying the nut turned. He's saying the prescribed torque of the nut doesn't provide enough force to hold the wheel in place. I too call this "loosening".

:checkmark: - Loosening from wear of mating surfaces.

I dont even know what torque I use. High strength bolts that big are quite tolerant of a good 1/2" impact.​

 

[ovrszd]

Here's another pic of a hub centric setup. In this case the nuts are multi-purpose. One side is tapered. In this application that wasn't needed so they were applied with flat face toward the wheel.

 

[JWR]

Here's a pic of a rear wheel. It's hub centric. The bolts/nuts prevent spinning and hold the wheel tightly on the hub. They do not keep the wheel centered. The nuts are flat on the backside and use a flat washer.



View attachment 590946

Yep, that's what I am familiar with. Though I thought 2 of the studs were bolts going inward.

 

[ovrszd]

Yep, that's what I am familiar with. Though I thought 2 of the studs were bolts going inward.

They are on smaller models. These pics are on my M9540.

 

[crazyal]

You keep saying that the nuts didn't loosen up, and I believe you. But I don't think that the nut loosening or not is the problem here. And it doesn't look like the diameter of the hole is either.

From a mechanical engineering point of view, conical nuts and tight-fitting wheel stud holes are nice, but those features are backups. In this type of joint, It should be the simple clamping pressure from the nut that does the work of keeping the wheel tight enough to the axle face so that it doesn't move.

From what you say, it simply looks like the clamping pressure is insufficient to keep the wheel from moving. And that is such a simple calculation that I can't believe that Kubota got it wrong. Al, when I look at that picture you posted of the stud, lock washer, and nut stack back at the beginning of this thread it just looks wrong to me. I seriously doubt that is a stock setup. Have you checked against an exploded parts diagram? It would be downright weird and unique if any joint like that was originally designed with a lock washer carrying the compressive force between the nut and wheel face.

So to me it seems like the nut and washer stack were assembled wrong when the tractor was new. Maybe by the dealer, or the tire shop, or some other place. At the least there should be a large hard flat washer between the wheel face and the nut.

rScotty

The exploded view on Kubota's parts diagram only shows the nut (item #210) and the lock washer (item #230). The bolts (item #2000) have captive lock washers on them. If you add an extra washer (my plan) then the bolts are too short as when they are tight the end of the bolt is flush with the inside of the axle. Since any length bolt is available I would expect Kubota to use a longer bolt if a washer was suppose to be used.

 

[crazyal]

Here's another pic of a hub centric setup. In this case the nuts are multi-purpose. One side is tapered. In this application that wasn't needed so they were applied with flat face toward the wheel.

View attachment 590953

If you look at your first picture vs your second the nuts used in the first picture are oversized. That's why you can't see much of the washer underneath. The second picture looks more like mine except for the fact that yours has washers.

 

[ovrszd]

If you look at your first picture vs your second the nuts used in the first picture are oversized. That's why you can't see much of the washer underneath. The second picture looks more like mine except for the fact that yours has washers.

The nuts are oversized because the torque spec is a lot higher than yours. Hard to tell with pics. Mine are a lot bigger.

The part about this that disappoints me is that your setup isn't hub centric. Even my little JD2210 is hub centric.

 

[crazyal]

The dish is probably 5/16" thick (maybe 3/8"). Not sure if that would be thick enough to countersink and use a lug nut. But I could use the good wheel as a template and make some rings with the same size center hole and bolt pattern. I easily could weld them onto the disk or even bolt them since there are 6 unused square holes in the middle of the dish. That would beef it up and give extra surface for the lug nut. It would make lining up the holes to get a nice fit on the axle pretty easy. I could also use the ring to make new holes in the dish while using the old holes as an extra place to weld the ring to the dish. Interesting idea that I hadn't thought of.

 

[crazyal]

The nuts are oversized because the torque spec is a lot higher than yours. Hard to tell with pics. Mine are a lot bigger.

The part about this that disappoints me is that your setup isn't hub centric. Even my little JD2210 is hub centric.

They are a centric hub. If they weren't I suspect the wheels would be moving in all different directions. I'm working this weekend but I'll try to remove one of the bolts and get an accurate measurement of the hole. I should be able to get multiple measurements to see if there's any elongation happening on the "good" wheel. Right now I'm basing that none is happening off of my visual inspection.

Here's a picture of the bolt. It's a M16 that a 24mm socket fits on. By my estimate that makes the outside of the lock washer about 28mm. That's not a lot of surface area to hold the wheel from sliding. The belliville washers I've got are 5/8" inside, 1 1/2" outside and are 3/16 thick.

 

[ovrszd]

For clarity let's examin this.

Hub centric means the hole in the center of the wheel fits tightly over a raised shoulder on the axle. Is this how yours is designed?