6" Wheel Spacers. What's likely to break?

[SDT]

re:
Nobody other than a design engineer at Kubota can reliably answer that question.

This is the only correct answer. Anything else is just unqualified guessing.

Actually he doesn't really know.... the guy TESTING the tractor IS the one who DOES know !

There's a software simulation package for microcomputers ,used around the World, supposed to be the cat's meow...'greatest thing since sliced bread'. I pointed out to a rather talented electrical engineer a simple,basic FLAW in EVERY schematic that was designed... 'works in the simulation', does NOT work in the Real World. I said I'll wager everything I own against his bank account. he declined.

Agreed, and Kubota is not going to spend the money to test such things with 6" wheel spacers when the maximum width spacers that they recommend and supply is 1 3/8".

SDT

 

[Mark_BX25D]

he declined.

I think I'll follow his wise example and not make any effort to enlighten you.

 

[TheOldHokie]

I think I'll follow his wise example and not make any effort to enlighten you.

You are both probably wiser than I.

Assuming the tool in question is FEA it is not foolproof but it is extremely reliable and is used in the structural design of everything from sub-atomic size probes to spacecraft and skyscrapers. Its a very reliable analytic for predicting when and where structural failures are likely to occurr. We could not build the things we do without it.

Real world wise I own an old B7200 which has been pushed well beyond its design limits and I have experienced 4 structural failures. I have broken both rear axles, the rear differential carrier, and the transmission case. In the case of the axles the failures were both radial fractures at the base of the splines on the outer drive member. The tractor did not overturn or pitch about - it just stopped moving. That repair was pretty simple and inexpensive. The cracked differential carrier was a lot more expensive and time consuming but equally unexciting. And lastly the transmission case was a crack that formed along the top back edge of the mounting flange. Expensive and labor intensive but equally boring from an opeational point of view.

I would expect any failures caused by overloading due to wheel spacers to be similar in nature - possibly expensive and time consuming to repair but not life threatening.

Dan

 

[Mossy dell]

Agreed, and Kubota is not going to spend the money to test such things with 6" wheel spacers when the maximum width spacers that they recommend and supply is 1 3/8".

SDT

Good point, SDT. When I configured my tractor on line, evidently I made a false assumption about spacers. I seem to have ended up with about 3" total of increased width. I'd assumed I could get 3" on each side and that my dealer had screwed up.

But from what I have read since, spacers were probably done at the factory. And, as you note, Kubota has set a limit. It seems conservative but that's Kubota's way and its call.

 

[TheOldHokie]

Good point, SDT. When I configured my tractor on line, evidently I made a false assumption about spacers. I seem to have ended up with about 3" total of increased width. I'd assumed I could get 3" on each side and that my dealer had screwed up.

But from what I have read since, spacers were probably done at the factory. And, as you note, Kubota has set a limit. It seems conservative but that's Kubota's way and its call.

Consider the factory tread width spacing on an L3901:

• 15-19.5 R4 - fixed at 45.1"
• 13.6-16 Turf - fixed at 43.9
• 11.2-24 R1 - variable from 43.8" to 50.8"

All of them are on the same axle and hub. The R1"s can be set ~3.5"" wider per side than the turfs and ~3" wider per side than the R4's. That of course neglects the added out to out distance provided by the increased tire width of the R4 and turf tires. Even taking that into consideration the 1.5" factory spacers are not pushing the envelope on R4's and even less so on the turfs.

Dan

 

[Mossy dell]

Dan, I got R14s so I wonder where they fall? Not sure the information you provided is in my manual.

 

[GreensvilleJay]

OK, have to ask, what are you doing on the slope ?
If say mowing. Maybe get a Ford N series or an A-C G, They'll be super stable on the slope.

 

[Henro]

Lots of good thoughts for consideration. Thanks to everyone for their input.

I have several months before I do anything (probably longer)…

 

[TheOldHokie]

Dan, I got R14s so I wonder where they fall? Not sure the information you provided is in my manual.

I would be very surprised if it was not. R14s are an optional tread for R4 and I would expect use the same wheels.

Dan

 

[TheOldHokie]

OK, have to ask, what are you doing on the slope ?
If say mowing. Maybe get a Ford N series or an A-C G, They'll be super stable on the slope.

I grew up around farmers and N-series tractors. I had two great uncles that joined the considerable ranks of those that died from N-series runaways and rollovers. My grandfather was an experienced heavy equipment operator that managed to survive two rollovers. I own two N-series of my own and multiple Kubotas that I purchased so I don't have to risk joining the considerable ranks of those that have died operating N-series on hillsides. Four wheel drive, reliable brakes, manageable gearing, and ROPS makes any Kubota vastly safer than any N- series.

PS> I forgot live hydraulics which is probably meaningless to most on this forum.

Dan

 

[SDT]

OK, have to ask, what are you doing on the slope ?
If say mowing. Maybe get a Ford N series or an A-C G, They'll be super stable on the slope.

Agreed. The 9/2/8N Fords have lower CG than just about any other farm tractors, certainly any Kubotas, possibly excluding LCG models.

Been operating both for decades and feel much more comfortable on my Ns than any Kubota with ROPS folded.

Of course, any tractor can be made to roll over if carelessly operated, e.g., inadequate tire pressure allowing down hill tire to peel from bead, and N series tractors do not have ROPS (or seat belts) as standard equipment.

SDT

 

[Mark_BX25D]

I would expect any failures caused by overloading due to wheel spacers to be similar in nature - possibly expensive and time consuming to repair but not life threatening.

I was thinking a sudden structural failure of the downslope axle housing might have the potential to be a lot more interesting than a premature bearing failure.

Mebbe?

 

[SDT]

I was thinking a sudden structural failure of the downslope axle housing might have the potential to be a lot more interesting than a premature bearing failure.

Mebbe?

Bingo, and exactly what I postulate in my very first reply.

 

[TheOldHokie]

I was thinking a sudden structural failure of the downslope axle housing might have the potential to be a lot more interesting than a premature bearing failure.

Mebbe?

Those housings are mighty heavy. Have you ever seen such a failure from any event?

Dan

 

[Mark_BX25D]

No, but I have seen other failures of heavy duty parts when they were subjected to stresses beyond their design.

Vibration is an amazing force.

 

[Henro]

I grew up around farmers and N-series tractors. I had two great uncles that joined the considerable ranks of those that died from N-series runaways and rollovers. My grandfather was an experienced heavy equipment operator that managed to survive two rollovers. I own two N-series of my own and multiple Kubotas that I purchased so I don't have to risk joining the considerable ranks of those that have died operating N-series on hillsides.

And SDT said this:

"...The 9/2/8N Fords have lower CG than just about any other farm tractors, certainly any Kubotas, possibly excluding LCG models."

A lower center of gravity implies less likely to tip over.

Seems like opposing views of the N-series tractors. Just wondering what I am missing here...

 

[TheOldHokie]

And SDT said this:

"...The 9/2/8N Fords have lower CG than just about any other farm tractors, certainly any Kubotas, possibly excluding LCG models."

A lower center of gravity implies less likely to tip over.

Seems like opposing views of the N-series tractors. Just wondering what I am missing here...

Ford N-series tractors do have a very low CG which is a major plus on side hill stability. But they are also two wheel drive tractors with horribly high gearing, no live hydraulics requiring you to constantly operate the clutch, a parking brake that is a joke, and abysmal down hill stopping power. All of that combined makes them difficult to operate at a safe speed and a major runaway threat on slopes. When your tractor loses traction and starts to slide down a hill out of control the low center of gravity offers scant protection for a collision, unpleasant trip over a precipice, and/or rollover caused by getting sideways at high speed.

How do you stop a runaway Ford 9N? See picture. The dent in the hood was not too big and I could pound it out with a big hammer. The radiator is a replacement and the grille and right side panel are a mangled mess in the scrap bin. Basically I had a choice between a tree or a cliff. I chose the tree.

That was not the first or last grassy sled ride that tractor has given me and ultimately I decided if I was going to continue to live on this hillside it was in my best interest to buy a tractor with better gearing, a reliable parking brake, 4wd traction for down hill braking, and a 3pt lift that I could safely operate. If anybody wants to come by I will let them take the 8N with a 72" finish mower on the back for a little test drive over the circuit I mow. Then youcan tale the bush hog up on the hill and try your hand at thicket clearing and let me know what they think. If you are accustomed to the control and comfort level you get with a "high CG" 4WD Kubota you better wear brown pants.

I grew up with an 8N tractor and the fond memories the evoke have given them a permanent place in my heart. I was probably first in the seat around two - with grandparental assistance of course. But the simple reality is that of all of the different tractors both 2WD and 4wd I have operated over the last 70+ years they are the least safe on hills. Two deaths and a bunch of broken ribs in my family alone.

Dan

 

[SDT]

Ford N-series tractors do have a very low CG which is a major plus on side hill stability. But they are also two wheel drive tractors with horribly high gearing, no live hydraulics requiring you to constantly operate the clutch, a parking brake that is a joke, and abysmal down hill stopping power. All of that combined makes them difficult to operate at a safe speed and a major runaway threat on slopes. When your tractor loses traction and starts to slide down a hill out of control the low center of gravity offers scant protection for a collision, unpleasant trip over a precipice, and/or rollover caused by getting sideways at high speed.

How do you stop a runaway Ford 9N? See picture. The dent in the hood was not too big and I could pound it out with a big hammer. The radiator is a replacement and the grille and right side panel are a mangled mess in the scrap bin. Basically I had a choice between a tree or a cliff. I chose the tree.

That was not the first or last grassy sled ride that tractor has given me and ultimately I decided if I was going to continue to live on this hillside it was in my best interest to buy a tractor with better gearing, a reliable parking brake, 4wd traction for down hill braking, and a 3pt lift that I could safely operate. If anybody wants to come by I will let them take the 8N with a 72" finish mower on the back for a little test drive over the circuit I mow. Then youcan tale the bush hog up on the hill and try your hand at thicket clearing and let me know what they think. If you are accustomed to the control and comfort level you get with a "high CG" 4WD Kubota you better wear brown pants.

I grew up with an 8N tractor and the fond memories the evoke have given them a permanent place in my heart. I was probably first in the seat around two - with grandparental assistance of course. But the simple reality is that of all of the different tractors both 2WD and 4wd I have operated over the last 70+ years they are the least safe on hills. Two deaths and a bunch of broken ribs in my family alone.

Dan

View attachment 74724

Sounds like you've never operated a Farmall, AC, JD, (pick a brand) row crop tractor on hills?

SDT

 

[SDT]

Those housings are mighty heavy. Have you ever seen such a failure from any event?

Dan

"Mighty heavy," perhaps, but made of aluminum on the OP's 2910.

SDT

 

[TheOldHokie]

Sounds like you've never operated a Farmall, AC, JD, (pick a brand) row crop tractor on hills?

SDT

No and I did not offer an opinion on their relative safety.

Dan