My letter to Kioti, loader rerepair, long

Bob_Skurka · May 23, 2006

This is an educated guess but if the cross tube penetrated thru the loader arms and was welded inside and out it would be much stronger. This was the way my old Kubota loader was and there was hardly any flex to it at all. The cross tube on my KL120 loader is only welded to the inside of the loader arm which is not as strong, as it is only pulling and pushing on the one side of the tube. This in my opinion allows this flex to take place. . . . 

Steve, the loader on most/all Kubotas have a round tube that goes through the loader arm and is welded on both sides. And I do agree with you that it is a very strong design with minimal flex.

However, the loader on my New Holland has the curved arm design very similar to the Kioti design, but without the access panel and the ingress/egress holes for the hoses. At about 200 hours there are no cracks in that loader, and there are no reports of similar stress cracks on the NH forum that I am aware of currently.

I suggest that the weakness of the loader is due to the combination of the 3 holes. Those three holes remove roughly ~40% of the metal from the backside of the cross brace. The metal removal, combined with the wrong grade and/or gauge of metal, is what I believe allows the flexing, and the consequent stress cracking.

Certainly the Kioti loader is an elegant design with the hidden hoses, but I believe those holes and the grade* of metal used are the root cause of these problems. As architects and designers would suggest, it is form over function at the expense of function. JMO.

*it seems clear that heavier gauge of metal, perhaps a different type (cold rolled vs hot rolled) is called for to prevent cracking caused by the flexing that is a likely result of the metal removal for the holes. If the back were solid, it might not need a different gauge/grade/type of metal because it would be slightly stronger and less flexible. Bear in mind I am not a metalurgist and do not pretend to be nor do I even play one on TV

Bob_Skurka · May 23, 2006

This is an educated guess but if the cross tube penetrated thru the loader arms and was welded inside and out it would be much stronger. This was the way my old Kubota loader was and there was hardly any flex to it at all. The cross tube on my KL120 loader is only welded to the inside of the loader arm which is not as strong, as it is only pulling and pushing on the one side of the tube. This in my opinion allows this flex to take place. . . . 

Steve, the loader on most/all Kubotas have a round tube that goes through the loader arm and is welded on both sides. And I do agree with you that it is a very strong design with minimal flex.

However, the loader on my New Holland has the curved arm design very similar to the Kioti design, but without the access panel and the ingress/egress holes for the hoses. At about 200 hours there are no cracks in that loader, and there are no reports of similar stress cracks on the NH forum that I am aware of currently.

I suggest that the weakness of the loader is due to the combination of the 3 holes. Those three holes remove roughly ~40% of the metal from the backside of the cross brace. The metal removal, combined with the wrong grade and/or gauge of metal, is what I believe allows the flexing, and the consequent stress cracking.

Certainly the Kioti loader is an elegant design with the hidden hoses, but I believe those holes and the grade* of metal used are the root cause of these problems. As architects and designers would suggest, it is form over function at the expense of function. JMO.

*it seems clear that heavier gauge of metal, perhaps a different type (cold rolled vs hot rolled) is called for to prevent cracking caused by the flexing that is a likely result of the metal removal for the holes. If the back were solid, it might not need a different gauge/grade/type of metal because it would be slightly stronger and less flexible. Bear in mind I am not a metalurgist and do not pretend to be nor do I even play one on TV

IslandTractor · May 23, 2006

*it seems clear that heavier gauge of metal, perhaps a different type (cold rolled vs hot rolled) is called for to prevent cracking caused by the flexing that is a likely result of the metal removal for the holes. If the back were solid, it might not need a different gauge/grade/type of metal because it would be slightly stronger and less flexible. Bear in mind I am not a metalurgist and do not pretend to be nor do I even play one on TV

 But you did stay in a Holiday Inn last night....right? 
/forums/images/graemlins/grin.gif /forums/images/graemlins/grin.gif

IslandTractor · May 23, 2006

*it seems clear that heavier gauge of metal, perhaps a different type (cold rolled vs hot rolled) is called for to prevent cracking caused by the flexing that is a likely result of the metal removal for the holes. If the back were solid, it might not need a different gauge/grade/type of metal because it would be slightly stronger and less flexible. Bear in mind I am not a metalurgist and do not pretend to be nor do I even play one on TV

 But you did stay in a Holiday Inn last night....right? 
/forums/images/graemlins/grin.gif /forums/images/graemlins/grin.gif

Bob_Skurka · May 23, 2006

But you did stay in a Holiday Inn last night....right?
/forums/images/graemlins/grin.gif /forums/images/graemlins/grin.gif 

As a matter of fact, I did, and now that you bring it up, did you know . . . /forums/images/graemlins/wink.gif

Bob_Skurka · May 23, 2006

But you did stay in a Holiday Inn last night....right?
/forums/images/graemlins/grin.gif /forums/images/graemlins/grin.gif 

As a matter of fact, I did, and now that you bring it up, did you know . . . /forums/images/graemlins/wink.gif

GeneD14 · May 23, 2006

( I suggest that the weakness of the loader is due to the combination of the 3 holes. Those three holes remove roughly ~40% of the metal from the backside of the cross brace. The metal removal, combined with the wrong grade and/or gauge of metal, is what I believe allows the flexing, and the consequent stress cracking. )

I agree with Bob's conclusions based on what we know about the problem.
One of the things that Kioti should be doing in a controlled setting is to duplicate the failure mode before assuming the cross member is the only problem. We don't know if the flexing in the cross member is being caused by the loader design or how it is mounted. The loader arms and mounting may have a geometry that induces high stress loads to the cross member?
Being in the automotive manufacturing industry I have see hundreds of various design/manf. defects and several recalls.
In a case like we are now seeing with the cracking issue we would typically handle it in the following way if the cross member is the root cause:
Produce "high strength steel" repair kits as quickly as possible for dealers to install that solve the problem and look professional.
Ideally we would like to send the dealers a new/improved arm assembly to switch out but my guess is that the cost would be to great.
It is a thousand times easier to quickly fix or repair these issues than wait for a tidal wave of customer complaints. (believe me I know)

GeneD14 · May 23, 2006

( I suggest that the weakness of the loader is due to the combination of the 3 holes. Those three holes remove roughly ~40% of the metal from the backside of the cross brace. The metal removal, combined with the wrong grade and/or gauge of metal, is what I believe allows the flexing, and the consequent stress cracking. )

I agree with Bob's conclusions based on what we know about the problem.
One of the things that Kioti should be doing in a controlled setting is to duplicate the failure mode before assuming the cross member is the only problem. We don't know if the flexing in the cross member is being caused by the loader design or how it is mounted. The loader arms and mounting may have a geometry that induces high stress loads to the cross member?
Being in the automotive manufacturing industry I have see hundreds of various design/manf. defects and several recalls.
In a case like we are now seeing with the cracking issue we would typically handle it in the following way if the cross member is the root cause:
Produce "high strength steel" repair kits as quickly as possible for dealers to install that solve the problem and look professional.
Ideally we would like to send the dealers a new/improved arm assembly to switch out but my guess is that the cost would be to great.
It is a thousand times easier to quickly fix or repair these issues than wait for a tidal wave of customer complaints. (believe me I know)

Bob_Skurka · May 23, 2006

It is a thousand times easier to quickly fix or repair these issues than wait for a tidal wave of customer complaints. (believe me I know) 

I think the tidal wave is nearly here. Kioti has a very small market share of the total tractor market, but Kioti owners have a very large percentage of the posts here on TBN (relative to market share) so it seems reasonable to suggest that we are seeing a disproportionate number of complaints about the loaders. And there are several threads about this issue for both models (the KL120 and the KL130 loaders). It strikes me that Kioti has only a fairly short window of time to do the right thing and get this fixed properly before their name is damaged.

The reality is that there are many more Kioti owners who are TBN members aware of this problem than those Kioti owners who are not TBN members, so the odds are very high that many Kioti owners have not yet found cracks. Now it is possible that Kioti is hoping to save money and stay quiet about this in hopes that the warrenty periods will pass before they fix the loaders.

And it certainly is cheaper to fix only the loaders that are reported than it is to do the right thing and fix all of them.

Bob_Skurka · May 23, 2006

It is a thousand times easier to quickly fix or repair these issues than wait for a tidal wave of customer complaints. (believe me I know) 

I think the tidal wave is nearly here. Kioti has a very small market share of the total tractor market, but Kioti owners have a very large percentage of the posts here on TBN (relative to market share) so it seems reasonable to suggest that we are seeing a disproportionate number of complaints about the loaders. And there are several threads about this issue for both models (the KL120 and the KL130 loaders). It strikes me that Kioti has only a fairly short window of time to do the right thing and get this fixed properly before their name is damaged.

The reality is that there are many more Kioti owners who are TBN members aware of this problem than those Kioti owners who are not TBN members, so the odds are very high that many Kioti owners have not yet found cracks. Now it is possible that Kioti is hoping to save money and stay quiet about this in hopes that the warrenty periods will pass before they fix the loaders.

And it certainly is cheaper to fix only the loaders that are reported than it is to do the right thing and fix all of them.