Finish mower tires popping off

[Dopp Creek]

I have a 6 ft Bush Hog finish mower with pneumatic tires at the four corners. The intent is that the mower "floats along the ground contours on the tires rather than the three point arms. Often, three to four times a year, one of the tires will roll off the bead and cut the inner tube. The tires are inflated, the spindles are free to spin, they have equal amounts of the height spacer bushings at each corner. I am at a loss as to why this happens so often. Am I supposed to lift the mower when I make a 90 degree turn? My expectation is that it will trail along wherever the tractor goes.
I would love to hear your input so I can put the annoying task of changing tubes behind me.

 

[will-max dairy]

I wish I had a picture of this... our finish mower isn't with me right now...

But, when you look at the front of your finish mower, there are the two pins that the three point hitch harms connect to the side... and then there is the point on top where the top link connects from the tractor. The mower should have a linkage there that hangs freely when not connected to the tractor... you are supposed to connect the top link from the tractor to that linkage... not directly to the mower. If you connect the top link directly to the mower, the angle of the mower relative to the tractor will be "forced" and either the front or back of the mower will dig in if you mow over moguls...

I wonder if you bought the mower used and that linkage is missing.

 

[will-max dairy]

Or, if you mow diagonally across ditches... or turn while in the bottom of a swale... you're going to put a lot of pressure sideways on the beads of the tires, even if they can swivel... they can only swivel so much... especially if the ground is soft and they are rutting in (which may be the biggest problem actually... is the ground you are mowing so soft that the tires are making ruts?)

 

[DoubleO7]

Current model:

 

[will-max dairy]

Current model:

View attachment 108515

Thanks agent 007... I circled the linkage that I was talking about before in the attached photo. With our finish mower, I attach the toplink to the end of that linkage toward the tractor (where the bolt is in the picture... our bolt is long gone... took it out and never put it back)... it allows the mower to flip and flop a little relative to the tractor.... until you lift the mower... then it flips up tight and holds the back end off of the ground.

Also... be careful of "downpressure" from your three point hitch. When the mower is set down, the lower arms should either be floating or set with some kind of draft control.

This is where our old Ford 2N shines. It has practically zero downpressure on the three point hitch. When I drop the mower... I just push the three point hitch control all the way down... and the mower is free to float up/down... whatever it needs. Combine that with the articulated top link, and the mower tires never even scuff the ground when we use it with the 2N... they just wander whatever direction they need, as the only pressure on them is the weight of the mower...

 

[DoubleO7]

Make sure the pivots for the wheels are well greased and sand free.

On mine if you turn too sharp and/or too fast, the wheels can't react soon enough and then plow thru.

But our lawn is not lush or dense. 40% open areas of basically sugar white beach sand.

 

[Dopp Creek]

THanks guys. Yes, my top link connects to the yoke you highlighted and yes the pivots are free to spin as well as float up and down within the range of spacers. The two points on the mower that connect to the lower three point arms have a pivot feature so they can float up and down (makes it simple to hook up). I had not considered the "float" of the three point arms (this is a Kubota 3430) but my recollection is that I can lift them up by hand when hooking up an implement.

 

[DoubleO7]

as well as float up and down within the range of spacers.

Does that mean you are missing some spacers?

Once you get the height you desire with spacers above the wheel yoke, the rest of the spacers are to go on top of the pivot tube.

There is not to be any floating up and down the pivot tube.

 

[will-max dairy]

Does that mean you are missing some spacers?

Once you get the height you desire with spacers above the wheel yoke, the rest of the spacers are to on top of the pivot tube.

There is not to be any floating up and down the pivot tube.

^^^^^^^ Great point...

The mower should be able to flip and flop relative to the tractor... and the wheel spindles are "adjustable" in the tubes... but yes, the spacers should be applied such that once the height of the wheels is adjusted... the spacers should hold the wheel spindles at a fixed height in the tube... which is accomplished by moving spacers between the bottom and top...not removing spacers completely...

If a wheel spindle slid down in the tube, it's not going to spin as freely, dangling from the mower.

 

[Dopp Creek]

Yes the spacers are above and below (based on cutting height requirements). What I mean is that with the spacers in place the tube can move maybe a 1/4" freely, as well as spin freely. That is one reason I am confused by the tire issue; I could understand it if the pivot was bound up some way.

 

[will-max dairy]

Yes the spacers are above and below (based on cutting height requirements). What I mean is that with the spacers in place the tube can move maybe a 1/4" freely, as well as spin freely. That is one reason I am confused by the tire issue; I could understand it if the pivot was bound up some way.

Then we're down to... is the ground mushy and the tires are cutting ruts that would keep them from pivoting in the tubes?

 

[Dopp Creek]

Yes the ground is damp now, but it has happened in the summer when the ground is firm. Another reason why I am confused. Thanks again for your input.

 

[Non-farmer]

My finish mower has solid tires, so this has never happened to me. I can't help but think there is some kind of mismatch between your tires and wheels. If that's not the issue, I have no clue what could cause this.

EDIT: afterthought - have you tried upping the pressure in the tires?

 

[showcrop]

disc, level and reseed.

 

[will-max dairy]

disc, level and reseed.

^^^^^^ another great point...

The tire can't pivot its way out of a bona fide divot or something like a woodchuck hole.

Also... are you running tubeless?

I would be tempted to put in tubes and some green slime (it wouldn't take very much) and call it a day...

 

[paul]

Is it the front tires, or the rear tires, or any random tire that is coming off the rim?

I’m with the guys that think the top link is your problem, if it doesn’t have enough free play for the mower and tractor to flex towards and away from each other, a lot of binding weight can be put on some of the mower tires in a short period.

Paul

 

[Non-farmer]

^^^^^^ another great point...

The tire can't pivot its way out of a bona fide divot or something like a woodchuck hole.

Also... are you running tubeless?

I would be tempted to put in tubes and some green slime (it wouldn't take very much) and call it a day...

Often, three to four times a year, one of the tires will roll off the bead and cut the inner tube.

 

[used red MN]

What’s the area like that you are mowing, could you classify it as strictly lawn grass? If there are tree saplings or brush shoots in it my guess would be that the tire/tube is being punctured deflates and then your final result happens. Mowing off the items mentioned about be can result in some nasty spears lurking to wreak havoc on less than robust tires.

 

[BarnyardEngineering]

When you say the wheels are "free to spin" do you mean that they are free to caster? Because what you describe happens when the wheel is shoved sideways with a heavy load on it, indicating that the wheels are NOT castering to follow the mower around the corner.

All four wheels should swing around like the front wheels on a shopping cart, casters. Just because they swing free when there's no load on them does not mean they swing with the weight of the mower sitting on them.

 

[showcrop]

What’s the area like that you are mowing, could you classify it as strictly lawn grass? If there are tree saplings or brush shoots in it my guess would be that the tire/tube is being punctured deflates and then your final result happens. Mowing off the items mentioned about be can result in some nasty spears lurking to wreak havoc on less than robust tires.

The OP told us that "one of the tires will roll off the bead and cut the inner tube." Sounds to me pretty definite.