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Here there are some graphs I obtained from data of pull-test made by University of Nebraska with a John Deere 8360R and a John Deere 8360RT.

The two tractors have no the same PTO power, so I use a corrective coefficient to compare them, thanks to the PTO test at 1800 RPM.

They have also not the same weight, so for comparing the pull force I divided it by the weight, to have an adimensional factor.

Here some results, if needed I can provide more graphs and elaborations.




This graphs has on X-axis the pull-force/weigth ratio, on Y-axis there is the slip expressed as percentage:

XtremeShack.com ... Free Image Hosting by XtremeHardware.com - confronto-cingoli - immagine 213166
 

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I look at it this way. a track is for a high draft load where you need a whole lot of traction. like a 90' air seeder with a 1000 bu cart and a 3000 gal liquid tank on hills going under 5 mph. with minimal compaction. However it is not efficient when you need speed and power like a 70' heavy harrow or a vertical tilllage unit where you need speeds in access of 8.5 mph. tracks loose their efficiency when you need speed.
 

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Discussion Starter #6
The drawbar test were done on an asphalt surface, so slip in different condition can obviously be different, but in this graph i rapresented the power that the tractor have at the drawbar, that is not the total power because the losses of transmission and for move all the components of tracks: <http://www.xtremeshack.com/photos/20140206139170784679748.png
From this power, we have to consider slip to obtain real power
 

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The drawbar test were done on an asphalt surfacehttp://
Not to get technical on you but if this was done by the University of Nebraska that would mean the Nebraska Tractor Test Lab (NTTL) which is a concrete track.

Thanks for this, takes a bit of desighphering but interesting.:)
 

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and your point is??? what are you trying to get across? your local soil type and equipment you use should determine the type of traction needed i would say.
 

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Discussion Starter #13 (Edited)
No, it is not. When you test tractors at the dyno to understand PTO power, the same you do to measure the power at drawbar, to analize tracks power losses.

This graphs are not about traction capability, that depends on soil condition, but about power losses on drivetrain, that not depends on soil.
 

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I look at it this way. a track is for a high draft load where you need a whole lot of traction. like a 90' air seeder with a 1000 bu cart and a 3000 gal liquid tank on hills going under 5 mph. with minimal compaction. However it is not efficient when you need speed and power like a 70' heavy harrow or a vertical tilllage unit where you need speeds in access of 8.5 mph. tracks loose their efficiency when you need speed.
Yeah, but it is so nice to be able to go over ditches/furrows at 8.5-10mph and not get launched into the top of the cab when pulling a vt tool with tracks.
 

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when i can put a promod car consistently into 6.2 second 1/4 mile pass after pass, i can say something about hp. sometimes it not all about how much hp, but how it is applied to the track, no different than a field, imho
 

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Yeah, but it is so nice to be able to go over ditches/furrows at 8.5-10mph and not get launched into the top of the cab when pulling a vt tool with tracks.
On our farm it is an absolute fight over the track machines. Nobody want to run the 800 duals, especially pullin at high speeds. Tracks are way smoother in 99.9% of the field. Anywhere there is ruts tires suck.
 

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No, it is not. When you test tractors at the dyno to understand PTO power, the same you do to measure the power at drawbar, to analize tracks power losses.

This graphs are not about traction capability, that depends on soil condition, but about power losses on drivetrain, that not depends on soil.
I was misreading the post and understand your point. I still think it's almost irrelevant though. Power to the drawbar in the field is what we all need.
 

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The interesting equation would be pull power for $ spent. What would happen if you spent for example the same dollars for the 8360t on a large frame 4WD would the tracks become irrelevant? Or perhaps more dollars on tire equipment either for floatation or traction.

I would in my case, spend on tracks for CTF as the tractors tires don't stand up to the weight loads on singles well.
 
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