D-17 vs JD 4720 MFD

I have 5 AC so I'm an AC man.All of the newer tractors are built shorter coupled...smaller engines producing more hp and generaly lighter, but with the heavier front end for the 4 wheel drive and front end loader I would guess it would out pull the AC.BStone

4720 is a compact tractor, but it has similar weight and tire size is close to the 17

I'd guess the D17, espescially if the deere had R4 tires all the way around and the D17 had R1s.  Also, I'd imagine the D17's drawbar was a little higher, giving it a slight advantage with weight trasfer to the drawbar.

  

Edited by farmtoybuilder - 02 Jul 2011 at 3:34pm

From an agricultural tractive effort perspective, if they have the same size rear tires, and the D17 is heavier, and you have 'em loaded down so that both tractors' front ends are in the air, the D17 will win.

Why?

Because tractive effort calculation is based on the diameter of driven wheel, ratio of weight on driven wheels vs. undriven, and finally, weight.

Under many conditions, having 4WD really gives a machine enhanced ability in maneuvering around sloppy areas, especially if there's a heavy load on the front end.  With front wheels in the air, however, having FWD becomes irrelevant.  There's no drag of undriven wheels, and all weight is on the rears, which is driven... that means they're on same playing field.

Finally, weight.  Tractive effort for ANY wheel-to-surface is substantially relative to the amount of force connecting the two together.  One can reasonable estimate the total drawbar force at incipient slip as being a percentage of the weight on drivers.

Notice that I never mentioned horsepower.  Once you've reached the point of incipient slip, adding more power increases slip, but the amount of added tractive effort is very small in comparison to the amount of horsepower added.  The Wismer-Luth study illustrates not only how to calculate the incipient slip point, but how much additional drawbar force is available as slip is increased.  It also indicates how to predict horsepower requirement to reach that slip level.

It is possible that the Deere could put enough engine to the wheels to generate substantial slip, and a little more drawbar effort, but the difference in weight between the two machines IS substantial... I highly doubt that even with it's horsepower advantage, that it would be able to generate the kind of slip required to equate to the 17's drawbar capacity...  but I'd sure like to try!!!

But that's comparing 'em solely on drawbar figures at unballasted conditions.  With ballast, the story changes pretty quick...

Well here is how it played out now remember the Deere is heavier , with the loader, cab ,and fluid. Also a long chain was used so no tractor would be lifting the other, or anyways minimize it.

i can not state on the 4720, but i have a 1999 model 5210 jd 2wd that is heavier than the 4720, it also has a NA,179ci motor vs the 149ci turboed in the 4720, and at best it is a 2x14 plow tractor and i know that a d17 will handle 3x14 in the same ground with ease