Tractor Sizing TRACTOR WEIGHT as a SINGLE CRITERION IN TRACTOR SELECTION

[Egon]

Bulletin:

[video]http://nasdonline.org/static_content/documents/7319/d002523.pdf[/video]

 

[aczlan]

Heavier tractors have larger diameter wheels/tires, increasing ground clearance. Larger rear wheels are an additional form of gearing.
Therefore, heavier tractors with large diameter wheels/tires have more tractive power pulling ground contact implements, pushing a loader bucket into dirt and pushing snow.
Larger wheels and tires and a longer wheelbase permit heavier tractors to bridge holes, ruts and tree debris with less operator perturbation.

Hmmm, the first part above (in bold) directly contradicts the second part below (in italics), unless there is a gearing change as well.
Larger wheels mean a higher ground speed and less torque on the ground for the same axle RPM, if a tractor has larger wheels, it generally gets different gears to increase the torque at the axle and make up for the larger tires.

Aaron Z

 

[MossRoad]

Hmmm, the first part above (in bold) directly contradicts the second part below (in italics), unless there is a gearing change as well.
Larger wheels mean a higher ground speed and less torque on the ground for the same axle RPM, if a tractor has larger wheels, it generally gets different gears to increase the torque at the axle and make up for the larger tires.

Aaron Z

Yep. :thumbsup:

 

[MossRoad]

Hmmm, the first part above (in bold) directly contradicts the second part below (in italics), unless there is a gearing change as well.
Larger wheels mean a higher ground speed and less torque on the ground for the same axle RPM, if a tractor has larger wheels, it generally gets different gears to increase the torque at the axle and make up for the larger tires.

Aaron Z

Yep. :thumbsup:

 

[Dranrab]

I am shopping for a tractor, so I thought this thread would be an educational read. I made it through 6 pages where most of the discussion was focused on CAPS, so if in the following 6 pages someone meaningfully discussed facts related to tractor weight, and I missed it, please forgive me.

Jeff makes a good point that we should determine the tasks we want a tractor to perform then select a tractor based on that. What he didn't do was qualify that further. I need to do light to moderate bush hogging on about an acre. I need to till soil for a garden that's close to an acre. I need to do some light to moderate box blading to smooth uneven surfaces. I need to scatter some gravel and smooth it out for a 350'x20' driveway.

How am I supposed to know how much tractor weight I need for that?

I am looking at 24-26 HP HST compact tractors in the 2000 pound +/- range. How much bare tractor weight do I need to pull 4-5' implements? From a physics standpoint, how does a 5 foot box blade know the tractor weight that is pulling it? That's a funny way of asking how weight matters in that equation.

I can see where weight matters if you have an FEL filled to capacity, but how many tractors will have the back end lightened to the point of danger or inefficiency with the FEL filled to capacity? How can that not be corrected with fluid in the tires and or an implement on the 3 point to counter the extra weight up front?

I have heard enough people tell me that that weight matters that I believe it, but nobody has demonstrated or provided facts to support that opinion in a way that has me thoroughly convinced. Show me how weight matters.

 

[k0ua]

Show me how weight matters.

The very first time you attempt to pull your boxblade up hill with all your tires spinning, you will then understand.

but how many tractors will have the back end lightened to the point of danger or inefficiency with the FEL filled to capacity?

Answer: ALL OF THEM!. You MUST have ballast, because as the tractors get larger and heavier, the FEL's get bigger, the buckets get bigger and will lift much larger loads, so they all must be properly ballasted.


You will even notice a big difference on your 25 hp tractor , pulling your 5 foot boxblade with and without loaded tires.

 

[jeff9366]

How am I supposed to know how much tractor weight I need for that?

Post #110: The most efficient way to shop for tractors is to first identify potential tractor applications, then, through consulataton, establish bare tractor weight necessary to safely accomplish your applications. Tractor dealers, experienced tractor owners and TractorByNet.com are sources for recommendations.

I have heard enough people tell me that that weight matters that I believe it, but nobody has demonstrated or provided facts to support that opinion in a way that has me thoroughly convinced. Show me how weight matters.

Your question is answered in Post #103.

 

[RickB]

Bulletin:

[video]http://nasdonline.org/static_content/documents/7319/d002523.pdf[/video]

Hmmm, the first part above (in bold) directly contradicts the second part below (in italics), unless there is a gearing change as well.
Larger wheels mean a higher ground speed and less torque on the ground for the same axle RPM, if a tractor has larger wheels, it generally gets different gears to increase the torque at the axle and make up for the larger tires.

Aaron Z

Excellent info.

 

[Dranrab]

The very first time you attempt to pull your boxblade up hill with all your tires spinning, you will then understand.


Answer: ALL OF THEM!. You MUST have ballast, because as the tractors get larger and heavier, the FEL's get bigger, the buckets get bigger and will lift much larger loads, so they all must be properly ballasted.


You will even notice a big difference on your 25 hp tractor , pulling your 5 foot boxblade with and without loaded tires.

If I ballast and I don't have hills, It sounds like lack of weight won't be an issue for what I intend to use a tractor for.

 

[atsah]

how does a 5 foot box blade know the tractor weight that is pulling it?

When you fill a 5ft box blade on a 24-26hp tractor you will find out in a hurry if you're tractor has enough tractor weight to pull it, weight = traction when pulling ground engaging implements..