Comparison Looking at buying new tractor, LS vs Kubota

[northpolefolks]

You are saying that the tractor must be babied or it will break itself. I have not found that to be true. Settling for that level of mechanical competence will become an excuse for lower and lower design margins as manufacturers learn they can get away with it.
larry

I was not saying it has to be babied. I know how to say that though when appropriate. It would sound like this "That tractor has to be babied".

To be clear I don't think you can pull on a 30,000 lb object with a smaller tractor and not expect something to break. A tractor, like all tools, has it's limitations. That's understanding limiations, not babying. I don't baby my Duramax, but I let it warm up and don't run around trying to pull 40 trailers loaded with rock. Does it mean I haven't broken tools by misuse? Nope. I have a few tools in the barn that are the aftermath of my miscalcuations and good intentions. LOL.

I disagree with the mechanical competence comment. If something breaks before it should, for no justifyable reason, I will buy something else that doesn't. Sevearal years ago a certain brand of tires had numerous failures and deaths resulted. The consumers didn't keep buying that particular tire, they quit buying them and the manufaturer fixed the problem. If a tractor continues to break when it shouldn't they won't be selling many of those tractors. John Deere, Ford, IH, Case, Kubota, NH to name a few show the benefits of good workmanship.

I don't think you have to baby the LS in any way, or I wouldnt have bought one.

 

[DavesTractor]

Northpole, you'll be happy with your LS, so don't worry about this little debate. As much as I would like you to own a Mahindra, I think you made a good choice since you have an LS dealer in your area, but no Mahindra dealers nearby. Having a good dealer nearby makes the owning experience better.

Just to wade in slightly on the broken drawbar issue, I think a guy should be able to hook a chain to his drawbar and pull until the tractor stalls or spins without breaking the tractor. But if it is at an odd angle and the chain is slacked and takes a big jerk, then we have some dynamics for which the engineers would be hard pressed to design. And if the part that broke is a bolt on part, and not a cast housing, then a couple minutes with a welder and we are good to go. Not to worry, enjoy your tractor.

 

[xtn]

A tractor with AGs on decent level ground will pull about 110% of its weight. I have measured this on my 2wd 2010 JD.
larry

I'm not sure how you guys are imagining this scenario. So I want to elaborate on the subject.

Saying that a tractor can pull it's own weight or not doesn't tell us much at all. We need to know what resistance that weight was pulled against. I can push an air craft carrier with my pinky finger if there is no friction or gravity to contend with.

If you use tractor Model X to pull its assembly line twin on flat and level ground, the amount of force the drawbar experiences might vary wildly from not much to a lot more than the Model X weighs, depending on the friction level - or traction - of the tires in/on the ground. I'm still not even talking about shock loading here, just smooth constant force.

What I meant when I said any decent tractor could exert more force than its own weight was that it could easily lift itself straight up if you wrapped a rope around the rear tire just right. Or, if you prefer, it could wench up its twin in the same manner. Well I doubt "easily" is the best word. I'm sure you would have to put it in low gear and get the revs up. Point is that it can exert more FORCE than it weighs. Well, assuming it can get the traction to do it.

 

[MtnViewRanch]

I have no idea what the criteria is, but I am pretty sure that none of the tractors ever tested in the Nebraska tractor tests have ever pulled their own weight. :confused3:

 

[xtn]

Okay I just read up on the OECD Code 2 testing procedures as used by the Nebraska Tractor Test Laboratory. The drawbar pull tests are to be performed on smooth, level, dry concrete.

I looked at a small sampling of test results, and find that every tractor comes reasonably close to, but does not match or exceed, its own weight in pulling force. That's exactly what one should expect under the circumstances, given teh likely coefficient of friction between tractor tire rubber and smooth, dry concrete.

Doesn't mean they don't have the power to pull more. Means they didn't have the traction to pull more. Here is a video sampling of a tractor being prepped for a Nebraska drawbar test.

[ame=http://www.youtube.com/watch?v=0OdEhoAJZOs]Challenger MT900 Burnout - YouTube[/ame]

It shows exactly what I'm talking about. That tractor certainly has the capability to put a lot more force on its drawbar if it wasn't traction limited.

 

[SPYDERLK]

A tractor with AGs on decent level ground will pull about 110% of its weight. I have measured this on my 2wd 2010 JD.
larry

I'm not sure how you guys are imagining this scenario. So I want to elaborate on the subject.

Saying that a tractor can pull it's own weight or not doesn't tell us much at all.

I measured actual force applied on moist solid turf pulling against a rooted tree. I used a force gauge . Slipped the clutch gently up to the point the wheels started to creep significantly. ... 7K# force from a 6K# tractor counterweight[bushog] combo. Ag traction on concrete is not all that good. Turfs would do better, but on smooth concrete probably still not as good a AGs on firm turf. Ags show about 1.1 traction coefficient when they can get the claws into substantial ground.
larry

 

[MtnViewRanch]

I measured actual force applied on moist solid turf pulling against a rooted tree. I used a force gauge . Slipped the clutch gently up to the point the wheels started to creep significantly. ... 7K# force from a 6K# tractor counterweight[bushog] combo. Ag traction on concrete is not all that good. Turfs would do better, but on smooth concrete probably still not as good a AGs on firm turf. Ags show about 1.1 traction coefficient when they can get the claws into substantial ground.
larry

Not arguing, just not the industry std. I believe that the Nebraska Tractor Test Laboratory sets the std and that is what most everything is gauged by that I know of.

 

[northpolefolks]

Northpole, you'll be happy with your LS, so don't worry about this little debate. As much as I would like you to own a Mahindra, I think you made a good choice since you have an LS dealer in your area, but no Mahindra dealers nearby. Having a good dealer nearby makes the owning experience better.

Just to wade in slightly on the broken drawbar issue, I think a guy should be able to hook a chain to his drawbar and pull until the tractor stalls or spins without breaking the tractor. But if it is at an odd angle and the chain is slacked and takes a big jerk, then we have some dynamics for which the engineers would be hard pressed to design. And if the part that broke is a bolt on part, and not a cast housing, then a couple minutes with a welder and we are good to go. Not to worry, enjoy your tractor.

Good points Dave. I am assuming the tractor didn't try to pull the stuck truck on a smooth flat surface. I assumed there were some odd angles thus the issue with the drawbar. All being said, fairly simple fix and move on fortunately.

 

[SPYDERLK]

Not arguing, just not the industry std. I believe that the Nebraska Tractor Test Laboratory sets the std and that is what most everything is gauged by that I know of.

Yeah, the concrete makes it repeatable. But with AGs it is unrealistic since they work by interlocking with the surface for traction. Not really much point in doing the test since it only demonstrates friction coefficient as opposed to traction coefficient.
larry

 

[Sublifer]

No, to all those making an excuse for the tractor drawbar failing. Proper design includes adequacy for function. We are not talking about about a failure due to jerking, but one that happened when the tractor was used to pull as hard as its traction allowed. That is what the drawbar is made to do. When you cant do that it is underdesigned.
larry

Seems almost everybody missed the part in that first post:
" After several tries and tractor jumping up and down which is hard on the drive train, I stopped and decided that maybe I could push him from the rear but couldnt do that either. Finally positioned my FEL against his dump bed to dump his load That is when I noticed my drawbar hanging out the back at an angle."
__tractor jumping up and down__ That implies angular and jerking forces. Sounds to me that he is pretty lucky that that is all that broke while trying to pull the 45,000 pounds of stuck weight...
The bouncing would explain why the chain didn't break before the cast iron...