Tractor weights. Is this really significant?

[texasjohn]

Fill to top of rim, leaving room for air.. needed for pressure and sidewall flex.

For 95% of us, traction is a moot point, 95% of the time.

It really matters when plowing very large acreage for hours on end.... where a small slippage is desired (maybe 15%) and R1's (loose field dirt) is the right answer. Here it translates into fuel efficiency versus dirt engagement efficiency versus acres per hour. A proper balance between RPM'S, speed, weight balance/distribution/ traction translates into optimal field work. How many of us do this, in reality.

Mostly, we use our tractors as a utility vehicle, doing lots of short term chores of very diverse kinds.

For FEL work, most important is 4WD+toothbar for digging into a pile of material and proper rear weighting (filled wheels and/or rear weight) for moving the material in a FEL. Rear traction will be OK if this is done, either R1 or R4 tires.

IMHO, R1's will dig a deeper rut and fill up with mud and spin just as soon as R4's. Difference is depth of rut.... result is still a spinning tire.

Rear wheel spin is best avoided by proper RPM'S and locking both wheels (operator action) when spin is likely as determined by experience.

I recently assisted a neighbor in cleaning out his dirt tank, prior to recent rains. It was slick mud, very slick, but mostly a firm foundation. I'd get a full FEL load, lock rear wheels as I carefully backed up the slick incline out of the tank, seeking to avoid wheel spin. Mostly this would work. Loaded rear wheels, 1000 lbs on 3ph via box blade/weights, 4WD.

When slippage did occur, it was over... I had to reenter the tank, reverse, and come backwards at speed to get past the slick point. Then, I'd put some drier (relatively) mud on the slick point and all would be good for about another 10 trips, then repeat. I have R4's, don't believe R1's would have been any different.

My point is that for best traction you need, IMHO in this order:
4WD
proper RPM's/horsepower...
loaded tires
proper 3ph weight
lock rear wheels together
R4's or R1's

Actual tractor weight does not matter (within reason).

 

[IslandTractor]

I would generally use the commonly recommended 75-80% of tire volume but there is a case to be made for 50% if the main reason for loading the tires is to increase stability on hills. At 50%, all the extra weight is below the axle and would proportionally add the most stability. Adding more than that would make sense if you knew exactly where the center of gravity was (and you stayed below it) but 50% would be a very safe bet. That last 20-25% of tire volume is almost certainly above the center of gravity on a tractor and therefore adds ballast (good) but not extra stability.

 

[aczlan]

I would generally use the commonly recommended 75-80% of tire volume but there is a case to be made for 50% if the main reason for loading the tires is to increase stability on hills. At 50%, all the extra weight is below the axle and would proportionally add the most stability. Adding more than that would make sense if you knew exactly where the center of gravity was (and you stayed below it) but 50% would be a very safe bet. That last 20-25% of tire volume is almost certainly above the center of gravity on a tractor and therefore adds ballast (good) but not extra stability.

When using a Calcium Chloride (Salt) containing filler you MUST fill the tire to above the top of the rim, this is to keep the rim from rusting out (when under water the salt will not promote corrosion the way that it will when exposed to air). If you fill with beet juice, WWF or something similarly non-corrosive this is not an issue.

Aaron Z

 

[IslandTractor]

When using a Calcium Chloride (Salt) containing filler you MUST fill the tire to above the top of the rim, this is to keep the rim from rusting out (when under water the salt will not promote corrosion the way that it will when exposed to air). If you fill with beet juice, WWF or something similarly non-corrosive this is not an issue.

Aaron Z

You are probably right but in a sealed tire the amount of oxygen available for oxidation of metal would be limited so while some rust might occur it is unlikely to be progressive. That issue could also be avoided by using an inner tube but like you suggest, beet juice or WWF might be a better choice.

 

[ChuckinNH]

"I know that some Kubota dealers like to talk about high grade metals that allow light construction but that is most likely bunk. Korean and Indian steel companies lead the world in steel production these days so I find it hard to believe the myths about "pot metal" used by Kubotas competitors." Well there are different grades of cast iron for sure, just ask anyone that rebores engines how many Honda engines they can do with one set of inserts VS Chevy, etc. engines. The other big difference is the casting method used. I have some experience with this. Investment castings are near net shape ( sometimes in the 90+ precentile) and just don't require as much steel. Sand castings, on the other hand, as used in many tractors are much less precise, and much more prone to air pockets. It also seems that lower grades of cast iron (not pot metal) are usually used. I have been in sand casting foundries, and watched them being poured, as well as spending time in investment casting foundries. ( I have seen air pockets in investment castings, but they are rare) Firearms from Sturm Ruger, for example are known to be very strong, and are made from investment castings for the most part. I do think that some companies are using Aluminum in their transaxles / hydrostatic transmissions, and I'm not sure that is a great plan if you are pulling / pushing on it.

Kubota, and John Deere practice "lean manufacturing", or "The Toyota Principle" manufacturing techniques. There is both good, and bad about that. The good thing is that the quality of parts is usually very high, and assembly is very well managed. The downside can be that much thought is given to just what the customer perceives as being worth paying for, and manufacturing costs are sometimes put ahead of considerations after the sale. An example of that is the Toyota Camry. Not this last design change, but the one before that, Toyota took 30% of the individual parts out of that car. I found that hard to believe until I read more, and found that many things that used to be individual parts are now sub assemblies, or modules. If you have to replace the front metal / bumper on one you will find that out very quickly when you get the bill, just as you will if you break a headlight on many newer tractors.

Most tractors that compete successfully in today's market are pretty sound units. It is important that you really be honest in looking at the expected use of anything you purchase. Some just are better at some things than others. Kubota, and Deere have the lions share of the smaller, and user friendly tractor market for a reason. Kioti, Mahindra, and others have invaded that market share for a reason too.

 

[sld]

A tractor that will not spin all 4 of its tires on good ground with loaded R1s is weak in the engine. One that is in any kind of mechanical danger doing this is just plain weak.
larry

I am much more worried about breaking something on the front axle than the rear if I were to overload the heck out of it.

The manual says not to fill or add wheel weights to the fronts so it is probably good advice.