Front tires caused axle failure...?

[RickB]

Tire radius / diameter was not a factor. Tire width / rim offset may have been. Consensus or not, you will never know for sure if the failure would have occurred with stock wheel equipment.

 

[Egon]

I値l suggest the wider tires put more stress on the system when turning. ( the outer edge of the tire has to cover more distance than the inner edge ) ( sorta the same as the requirement foe a differential )

 

[oosik]

I only use 4WD when absolutely necessary. There is no need for the extra stress on driveline components. Things will wear out soon enough without "encouragement".

 

[dragoneggs]

I only use 4WD when absolutely necessary. There is no need for the extra stress on driveline components. Things will wear out soon enough without "encouragement".

Me too, but it is necessary about 3/4 of the time on my property!

 

[/pine]

Tire radius / diameter was not a factor. Tire width / rim offset may have been. Consensus or not, you will never know for sure if the failure would have occurred with stock wheel equipment.

This is 100% conjecture...no different than any of the other speculations...unless of course you have actual comprehensive analytical scientific engineering analysis...??

 

[5030]

Wow 25 comments, some are correct, some are total BS. Kubota (and every other manufacturer has specific lead-lag specifications and when you change the front's you have to change the rears to, too maintain the correct lead-lag ratio or no matter what brand it is, if it's front wheel assist and you run in FWA much, you'll eat up the front driveline. Tire offset has nothing to do with it. On my units, both front and rear rims are adjustable for track.

The tire circumference isn't however., that is where the lead-lag ratio comes in. Tire width is inconsequential as well, the important thing again is the lead-lag ratio.

You ate up the FWA because your lead-lag ratio was focked up.

Finally, I only use FWA when necessary. 95% of the time I'm in 2wd. Use the front axle is turning as well as the prop shaft and transmission input gearset but it's not locked into mesh in the gearcase.

 

[5030]

This is 100% conjecture...no different than any of the other speculations...unless of course you have actual comprehensive analytical scientific engineering analysis...??

No, it's not at all. Lead-Lag ratio is what impacted his front axle. If you have (x) sized (od) tires on the front, width means zip, you need (x) sized (od) tires on the rear. How it works and tread width or wheel offset has zip to do with it.

I know you are gonna as what is the correct lead-lag ratio with different tire sizes and I'll say ask an authorized dealer, they will know. There is a rather complex formula to determine correct lead-lag but math isn't a strong point with me. asking my dealer is much easier.

 

[/pine]

No, it's not at all. Lead-Lag ratio is what impacted his front axle. If you have (x) sized (od) tires on the front, width means zip, you need (x) sized (od) tires on the rear. How it works and tread width or wheel offset has zip to do with it.

I know you are gonna as what is the correct lead-lag ratio with different tire sizes and I'll say ask an authorized dealer, they will know. There is a rather complex formula to determine correct lead-lag but math isn't a strong point with me. asking my dealer is much easier.

See my posts #5 and #7...they are both about what you are referring to as "lead lag"...it has everything to do with the R.C. (rolling circumference) of the front tires and the ratio to the size of the rear tires...!

 

[/pine]

...The difference in diameter that could result in drive-train damage amounts to a scant 0.22 to 0.23
inch, or just less than a quarter of an inch....

http://www.ndtirepartner.com/resources/Tire diameter sheet.pdf

 

[RickB]

This is 100% conjecture...no different than any of the other speculations...unless of course you have actual comprehensive analytical scientific engineering analysis...??

My extensive experience leads me to that conclusion, along with supplied static loaded radius info provided by the OP.
Whether anyone follows, I do not care.

 

[oosik]

About the only time I use 4WD - snow plowing. Otherwise - it's crossing the "moat". The "moat" is the interconnect between my little ten acre lake and the big 125 acre lake. And even at that - I only use 4WD while crossing because it could be soft. Weeds grow too high to see if it's bone dry, muddy or full of water. The "moat" is about 120' across and 300 yards long. I've learned the HARD way about this crossing. Never damaged anything but had some thrilling moments. Like - having my first tractor fall thru the ice while attempting a winter crossing. This aerial pic of the property is at a time when the big lake is not completely full. There have been years when the big lake goes completely dry. It's a max of 8' deep. My little lake is 80' deep - right down the center line. View attachment 663638

 

[LouNY]

That can and has happened to every brand of tractor, some times it can be traced to tires some times not.
Next week the New Holland T6050 gets torn down as one front hub is loose and wobbling, hopefully just bearings and seals.

 

[Diggin It]

Like a few others have stated, I have no choice. I've tried to get down my hills without it and left some rather deep skid marks in the dirt where both rears cut through the turf. And that was on dry grass. I can't even think about coming uphill without it.

I have two fairly small areas I can mow in 2WD and of course any time I'm on pavement. Of my 260 or so hours on the clock, probably 200 - 225 have been in 4WD. It's simply not safe to not be.

 

[oosik]

It's nice to have when you need it.

 

[thoner7]

Wow 25 comments, some are correct, some are total BS. Kubota (and every other manufacturer has specific lead-lag specifications and when you change the front's you have to change the rears to, too maintain the correct lead-lag ratio or no matter what brand it is, if it's front wheel assist and you run in FWA much, you'll eat up the front driveline. Tire offset has nothing to do with it. On my units, both front and rear rims are adjustable for track.

The tire circumference isn't however., that is where the lead-lag ratio comes in. Tire width is inconsequential as well, the important thing again is the lead-lag ratio.

You ate up the FWA because your lead-lag ratio was focked up.

Finally, I only use FWA when necessary. 95% of the time I'm in 2wd. Use the front axle is turning as well as the prop shaft and transmission input gearset but it's not locked into mesh in the gearcase.

So my lead-lag ratio should have been unchanged, if the online posted rolling circumference measurements are accurate.

Especially when considering the stock front tires probably lost 3" in diameter (or more) due to tire wear.

 

[5030]

...and conversely, the rears should also be loosing circumference as well. When I replace tires I replace all 4 at one time. In my case that can be upwards of 6 grand.

The only time lead-lag comes into play is when the front axle is locked into the FWA mode. In RWD it don't really impact the front gears because the front gears aren't fighting the rear gears.

Why, despite the fact my lead-lag ratio is correct, I only engage FWA when I need to. No reason to use a tractor with FWA engaged constantly. I do a lot of roading and if I was in FWA all the time, I'd go through tires like water. FWA always contributes to tire scrub, especially when turning.

 

[LouNY]

...and conversely, the rears should also be loosing circumference as well. When I replace tires I replace all 4 at one time. In my case that can be upwards of 6 grand.

The only time lead-lag comes into play is when the front axle is locked into the FWA mode. In RWD it don't really impact the front gears because the front gears aren't fighting the rear gears.

Why, despite the fact my lead-lag ratio is correct, I only engage FWA when I need to. No reason to use a tractor with FWA engaged constantly. I do a lot of roading and if I was in FWA all the time, I'd go through tires like water. FWA always contributes to tire scrub, especially when turning.

The rears will lose loaded radius much slower then the fronts will, normally we will go thru 2 sets of front tires before needing a pair of rears.
Also the effective loaded radius can be affected easily and greatly by varying the tire pressure.
I'm not aware of many people that leave the front axle engaged when roading a tractor.
A loose gravel road it wouldn't be that rough on it anyways.
An easy way to check is to look at the tire prints in a damp dirt roadway and see how much the front is leading or lagging the rear.

 

[5030]

The rears will lose loaded radius much slower then the fronts will, normally we will go thru 2 sets of front tires before needing a pair of rears.
Also the effective loaded radius can be affected easily and greatly by varying the tire pressure.
I'm not aware of many people that leave the front axle engaged when roading a tractor.
A loose gravel road it wouldn't be that rough on it anyways.
An easy way to check is to look at the tire prints in a damp dirt roadway and see how much the front is leading or lagging the rear.

I suspect owners of smaller FWA units leave their FWA engaged a lot more than we do. Like your auto. If it's 4 wheel drive, you don't run in 4wd unless the conditions warrant it and you don't mix tire sizes (circumference) front to rear either. Same principles apply there as well as tractors. Just as easy to destroy a front differential on a 4wd truck or car as it is with a tractor.

I rarely have either of my Kubota's in FWA.

 

[CoyPatton]

If they can be swapped without the tire getting into the frame it would reduce any stress from the wider tire and rim offset.

Note the potential inference issues with this move. Tires getting into the tractor frame can cause a world of new troubles, depending on how and where the tractor is used, these could be deadly.

 

[CoyPatton]

I would not leave your tractor in 4wd all the time no matter what. The reason is because it creates a lot of stress in the driveline every time you turn.
When the 4wd is locked in and you turn, the front wheels are traveling different distances in the turn from each other and different than the rears, so you create bind all the time. When you have a loaded bucket and you are turning in 4wd, you are really stressing the system. Plus you can wear the tires a lot faster.
I am not saying that leaving it in 4wd is what caused your trouble, but it didn't help. I would guess having those wide tires stuck all the way out probably stressed the bearings and one thing led to another. Based on what you said your circumference numbers were, I wouldn't think you would be introducing so much lead that you would break the driveline.

For what its worth, I don't ever use my 4wd unless I need it, and then I lock it in and as soon as I don't need, I unlock it. Actually, for what I do, I seldom need it.

I have to agree with this assessment. You should not leave 4wd engaged all the time. Never on hard surfaces including hard packed soil!
If you happened to be in the unusual environment where you need to use 4wd all the time, just accept that means frequent replacement of wheel bearings and listen for unusual noises from the front end and when heard check it out soon (like yesterday).
In my opinion, you bought a tractor that had issues. Those issue were probably created by a combination of factors. The stresses of a widened front stance work hard on the bearings. The constant use of 4wd worked hard on the gears (especially if used on hard surfaces including but not limited to hard packed soil) combined the 2 stressors worked on the others damage.

While wider tires are great for creating a larger footprint for distributing weight, they also create greater stress for steering and greater resistance for rolling (increase that for traction in in 4wd mode).