BX 23s Amazon Wheel spacers

[RStricker]

Holy smokes, Stricker, that is quite a story! I put 2 inch Bro-Tek wheel spacers on my 2009 BX25, and I haven’t had any problems at all.

I checked the axle part number online: it shows the same axle being used on the BX22 thru BX25, and lots of other models.

I just measured my old broken axle (I never throw anything away that might have a use someday). It’s 6-1/8” from the flange face to the break. My 3” spacers changed that moment arm to 9-1/8”, an increase of 49%. Your 2” spacers therefore add ~33% to the moment arm. Is this too much? I don’t know. It’s a function of how heavily the axle is loaded, how many times the axle is rotated (each rotation adds one more completely reversing loading cycle on the axle shaft), and what is the maximum stress in the axle shaft. So every machine will have a different response, based on the machine usage.

 

[Henro]

I don’t see anyone here addressing the issue of the added stress on the axles due to wheel spacers.

I have an older BX-23 which I bought used in 2015. For the sake of added stability I bought and installed a pair of 3” Bro-Tek wheel spacers. Five years later I had a very expensive repair. The added bending moment on the axles caused a fatigue failure that not only broke an axle, but snapped the end off the very pricey aluminum housing that the axle rides in. Further, the tractor was jerked sideways by the loss of one back wheel and hit a tree. My employee who was using the tractor said that the impact was such that if he hadn’t been wearing the seat belt, he’d have been thrown off the tractor. (And it wasn’t even going very fast – it was in low range.)

Maybe the newer models have a larger diameter axle and can accommodate the added bending moment, but you really should check with Kubota to see what they recommend.

This is the first time I have read of a failure that might be attributed to wheel spacers! At least on a BX. And I read a lot on the tractor forums.

Trying to understand exactly where the break occurred. Sounds like it was between the two bearings that the axle passes through, and that is why the housing was damaged, as compared to if the axle had snapped off outside the outermost bearing.

Also, just thinking out loud, but since you bought the tractor used, who knows what abuse it suffered before you took possession. So possibly the axle was damaged to some degree before you added the spacers?

No doubt that adding spacers changes the mechanics of the system. Risk benefit decision.

 

[RStricker]

The abuse that the tractor suffered prior to my ownership was primarily the indignity of using the FEL to clean cow manure from a dairy barn!

I've attached a pair of pictures to show where the damage occurred. I changed out both axles, not just the broken one, so you can see where the outer bearing is for comparison purposes. The break occurred on the inboard side of the bearing. This is because there is a groove cut in the shaft to hold a snap ring the keeps the bearing in place. So this groove is the weakest point in the maximum stress area. The second picture is a snapshot of the broken section. The fracture pattern shown is what you would typically expect a fatigue fracture of a shaft to look like.

And the reason the housing was damaged is that the break occurred on the inboard side of the bearing, therefore the bearing underwent a large twisting moment as the axle broke. This twisting tried to separate the machined recess that it was in, thus causing the housing to fracture.

 

[wawajake]

I also put 2 in brotek spacers on my 2008 bx2660, no problems, but one factor someight be missing will be the quality of the studs provided with the " cheaper priced " spacers. And that won't be noticed until a few years later and many wheel removals later .