BX23S Wheel Spacers Recommendation

[GreensvilleJay]

Adding 'duallies' is pretty easy,several garden tractors back in the 70s had them.
Easy method is to cut a steel cylinder the correct length , as a spacer and then use long bolts/studs to secure outer wheel-->spacer--> inner wheel-->hub.
The diameter of the spacer is such that it's just less than the 'bead' of the rim.

 

[Henro]

What's the largest offset that can be safely run on a BX?

I stacked (2) 2" for a 4" offset (each side), can I go to 6"?
(I haven't found a need, yet.)

No mower deck, 600# chipper on the back 3 point hitch (so there's a stress/wear concern).

This is a question that has been asked many times and for which there doesn’t seem to be a quantifiable answer offered. (Yes I know it can be calculated ).

Nobody can disagree that adding spacers increases the stress on the real axles and bearings and whatever. The question is how much? And if the increase is detrimental.

I remember years ago one guy, at TBN I think, doubled up both the front and rear wheels on his BX. Posted YouTube videos of it plowing garden or whatever. I believe he at some point removed the dual wheels. I don’t remember why, or even if he said why, but it was not because he broke something.

What I found over the years is that everybody has an opinion, but rarely give examples of broken axles, or whatever, that resulted from adding wheel spacers.

My son-in-law has been using 2 inch wheel spacers on his BX 23S for about three years now without any issues. He uses the tractor a fair amount for work with the backhoe/loader. He doesn’t have a mower. No issues so far.

I could only put (I think) 1.25 inch spacers on my BX because I have a MMM.

With my larger B2910 I had to buy spacers made specifically for it because I couldn’t find anything like the eBay jeep spacers. I decided to go with 4 inch and I’m happy with it. My rationale was I’d rather break my tractor than break my neck, so I’ll take my chances breaking the tractor. I don’t really expect to though…

 

[WI_Hedgehog]

Thinking about doubling-up on wheels...

The torque moment on the axle is: T = (d)(F)

If we say the BX wheel is "X" in width and also about the same distance from the internal transmission bearing, the distance from the bearing is 2X, and the torque calculation is (2X)(F).

By adding another wheel and rolling over a rock with the outside wheel the torque on the axle would be: (3/2X)(F), effectively a 50% increase over the design. Probably not a good idea.

If the rear tire is 18" wide we divide that by 2 so the weight is in the center of the tire, and add 18" if we assume the inside edge of the tire is 18" from the internal bearings:
(18" / 2) + 18" = 27"

If the three point hitch is carrying 500# and the rear end mass of the tractor is 1/3 the tractor weight (1,410# * 1/3), the weight on each of two rear axles is:
(500# + 470#) / 2 = 485#

The torque is:
(27")(1 foot / 12") (485#) = 1,090 ft*lbs

Adding 4" spacers:
(27" + 4")(1 foot / 12") (485#) = 1,252 ft*lbs

((1,252ft*lbs / 1,090ft*lbs) -1) * 100% = 15% increase (or thereabouts)
(which is simply: (4"/27")(100%) = 15%

To stay within Kubota specifications for the BX2370, carry 15% less weight less than the maximum capacity.
Three point hitch. Max.lift force 24 in. behind lift points: 680 lbs

(680 lbs)(85%) = 578#

The heaviest thing I carry is the WoodMaxx MX-8600 Chipper which specs. at 580#. so...with Pat's Quick Hitch and the chipper center of mass likely being more than 24" behind the lift points it's a consideration to use 2" spacers (or at least treat the tractor gently with 4" spacers).

Who said, "Use math????"

 

[Henro]

I’m not mechanical in background so I probably tend to ask questions that are quite simple.

But I’m wondering if torque for what you’re describing is the right term. For example, an engine produces horsepower and torque output. So I always think of torque as the twisting moment on a shaft.

So as far as stress to the rear axles on a tractor as the result of adding wheel spacers, I’m wondering if bending moment, or something like that,, might be the right term?

Anyway, in this case, it’s probably just semantics. But one thing we don’t know is what the ultimate limit is for the rear axle assembly, and what safety factor was built into the design.

I wonder what the backhoe on the BX23S weighs? Perhaps similar or more than a chipper?

 

[rc51stierhoff]

Thinking about doubling-up on wheels...

The torque moment on the axle is: T = (d)(F)

If we say the BX wheel is "X" in width and also about the same distance from the internal transmission bearing, the distance from the bearing is 2X, and the torque calculation is (2X)(F).

By adding another wheel and rolling over a rock with the outside wheel the torque on the axle would be: (3/2X)(F), effectively a 50% increase over the design. Probably not a good idea.

If the rear tire is 18" wide we divide that by 2 so the weight is in the center of the tire, and add 18" if we assume the inside edge of the tire is 18" from the internal bearings:
(18" / 2) + 18" = 27"

If the three point hitch is carrying 500# and the rear end mass of the tractor is 1/3 the tractor weight (1,410# * 1/3), the weight on each of two rear axles is:
(500# + 470#) / 2 = 485#

The torque is:
(27")(1 foot / 12") (485#) = 1,090 ft*lbs

Adding 4" spacers:
(27" + 4")(1 foot / 12") (485#) = 1,252 ft*lbs

((1,252ft*lbs / 1,090ft*lbs) -1) * 100% = 15% increase (or thereabouts)
(which is simply: (4"/27")(100%) = 15%

To stay within Kubota specifications for the BX2370, carry 15% less weight less than the maximum capacity.
Three point hitch. Max.lift force 24 in. behind lift points: 680 lbs

(680 lbs)(85%) = 578#

The heaviest thing I carry is the WoodMaxx MX-8600 Chipper which specs. at 580#. so...with Pat's Quick Hitch and the chipper center of mass likely being more than 24" behind the lift points it's a consideration to use 2" spacers (or at least treat the tractor gently with 4" spacers).

Who said, "Use math????"

Thinking about doubling-up on wheels...

The torque moment on the axle is: T = (d)(F)

If we say the BX wheel is "X" in width and also about the same distance from the internal transmission bearing, the distance from the bearing is 2X, and the torque calculation is (2X)(F).

By adding another wheel and rolling over a rock with the outside wheel the torque on the axle would be: (3/2X)(F), effectively a 50% increase over the design. Probably not a good idea.

If the rear tire is 18" wide we divide that by 2 so the weight is in the center of the tire, and add 18" if we assume the inside edge of the tire is 18" from the internal bearings:
(18" / 2) + 18" = 27"

If the three point hitch is carrying 500# and the rear end mass of the tractor is 1/3 the tractor weight (1,410# * 1/3), the weight on each of two rear axles is:
(500# + 470#) / 2 = 485#

The torque is:
(27")(1 foot / 12") (485#) = 1,090 ft*lbs

Adding 4" spacers:
(27" + 4")(1 foot / 12") (485#) = 1,252 ft*lbs

((1,252ft*lbs / 1,090ft*lbs) -1) * 100% = 15% increase (or thereabouts)
(which is simply: (4"/27")(100%) = 15%

To stay within Kubota specifications for the BX2370, carry 15% less weight less than the maximum capacity.
Three point hitch. Max.lift force 24 in. behind lift points: 680 lbs

(680 lbs)(85%) = 578#

The heaviest thing I carry is the WoodMaxx MX-8600 Chipper which specs. at 580#. so...with Pat's Quick Hitch and the chipper center of mass likely being more than 24" behind the lift points it's a consideration to use 2" spacers (or at least treat the tractor gently with 4" spacers).

Who said, "Use math????"

Good day.

I am not sure about the math, but I would think doubling the wheels (I am assuming the rears but it would be internet worthy if you only did the fronts) would greatly increase traction…not sure what that would do to the axles? In my limited experience with a BX it ran out of traction before it did power. So the question would be is the extra traction helpful or hurtful? Whatever you do, take some pics and share them! Bonus points for your OTT Online Presence if you add a stack and roll some coal while you are at it

 

[WI_Hedgehog]

@Henro : A simple comparative perspective is maybe "close enough" because unlike Kubota Engineers we're not going to do the math for extreme situations like they do. You're right though, I'm not figuring the bearing loads correctly, just looking at the big picture to ballpark what stress 4" spacers add to a BX to see if 6" is even viable. In my case since I'm at or near the tractors limits without spacers I should reduce stress elsewhere by the same amount as spacers add, meaning 6" aren't practical for me and with 4" spacers I should reduce stress by something like 15%. (general bearing considerations)

@rc51stierhoff : Doubling the front wheels is an interesting thought. The potential down-side might be the front axles that according to other members here and the dealer are already highly stressed under load. The best option seems to be "buy a bigger tractor" (or in my case learn more about the one I have).

 

[Henro]

In my case since I'm at or near the tractors limits without spacers I should reduce stress elsewhere by the same amount as spacers add, meaning 6" aren't practical for me and with 4" spacers I should reduce stress by something like 15%. (general bearing considerations)

I don’t really know anything, so I’m not trying to make a point or anything like that. But my impression is that you’re making an assumption that the weight rating on the three point hitch lift has something to do with possibly breaking axles or damaging something related to the axles.

Kubota could just as well be stating the capability of the hydraulic system to lift that weight on the three point hitch. In other words, the hitch can’t do more than that.

Or it could be that if the hitch can do more than that, the amount of weight taken off the front wheels due to the seesaw effect over the back axle, might cause other concerns such as safety because it could impact steering.

Again, like I said, I’m not sure. So I just suggest this has food for thought.

What kind of side slopes are you desiring to cross with your BX? I mean, measured in degrees rather than percent…

 

[WI_Hedgehog]

I don’t really know anything, so I’m not trying to make a point or anything like that. But my impression is that you’re making an assumption that the weight rating on the three point hitch lift has something to do with possibly breaking axles or damaging something related to the axles.

Kubota could just as well be stating the capability of the hydraulic system to lift that weight on the three point hitch. In other words, the hitch can’t do more than that.

Or it could be that if the hitch can do more than that, the amount of weight taken off the front wheels due to the seesaw effect over the back axle, might cause other concerns such as safety because it could impact steering.

Again, like I said, I’m not sure. So I just suggest this has food for thought.

What kind of side slopes are you desiring to cross with your BX? I mean, measured in degrees rather than percent…

Great questions and well put. I didn't measure (which I probably should have), though have what a friend described as "really steep slope to be taking a tractor up" and it pitches to the left by about 7°, so when wet is a bit concerning as it also has rocks in non-optimal places.

Thinking about the whole wheel spacer subject I decided to stay with 4" maximum per side, from what other forum members add to a BX and from simple math it seems a relatively good balance (I'm worried about creating excessive stress on the bearings, not necessarily breaking an axle).

Looking at the slope I decided to put in a different path up the hill and gave the wood that needed to be cleared to a neighbor. It's a much safer path; I go up empty and fill the front bucket and the empty weight bucket on the rear with wood and tractor that down the hill--much easier.