Ole_Hickory
Silver Member
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I wonder why this is ? Does this mean JD thinks a gear tranny would not hold up to the torque of the new JD 4720 ? I wonder what John Deeres reasoning is ?
Hydro only on the new JD 4720
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rockyridgefarm
Elite Member
Actually I am floored that there are so many models... I was just sure they'd cut the number of choices way down...
Woodbeef
Veteran Member
I'm starting to wonder if this is a new marketing ploy by the spin-doctors at Deere. This makes the 2nd time the largest tractor within a series is only available with a shiftless tranny. Will the other series go this way also as they are renewed,I wonder? Seeing as how Cowboydoc is so tight with Deere maybe he can shed some light on this for us?
My opinion is that Deere seems to market the top end model with the more expensive options standard... kinda like car manufactures "bundling" the items that are optional on lessor models. I'm sure it's driven by a few factors - ease of manufacturing - it simplifies the process, which in turn reduces cost - which in turn probably means more $$ for them.
rockyridgefarm
Elite Member
Don't forget, they have 5xxx's to sell. If you want something that big, and a gear transmission, they may make more sense, anyway.... This gives a Hydro in that size range, without adding one to the 5 series. Makes sense...
timb
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- Deere 4710/reverser, JD 318 (still needs TLC), JD LT160
I wouldn't be surprised if there is an actual mechanical limitation involved. All transmissions have input torque limit ratings. Since it appears that Deere didn't change anything from the bell housing back - and since the 4720 has a peak torque (154 ft. lbs @ 1440 rpm) some 42% higher than the highest force a 4000 ten series reverser ever saw (108 ft. lbs. @ 1700 rpm on the 4710) we might just be seeing the limit of that tranny/clutch.
(I tried to quickly find specs on the clutch size on the 5000 series but couldn't. The 4710 (and presumably the 4720) use a 5.1 inch wet clutch pack. I'll bet the 5220 (peak torque only around 130?) has significantly more clutch area and a tranny capable of more torque input.)
On the hydro on the other hand - there is power loss in the coversion of mechanical to fluid to mechanical energy (the hydro pump and motor) that will bleed some torque off - and the ability to set a relief valve to a point that the hydro motor never feeds more power into the rest of the mechanical geartrain than it can handle.
Which would make for a fascinating experiment - (PTO ratings aside) would a 4720 hydro have more actual pull grunt than a reverser 4520 at the rear wheels?
I wonder if due to their power levels these twenty series will ever see a Nebraska test?
Tim
(I tried to quickly find specs on the clutch size on the 5000 series but couldn't. The 4710 (and presumably the 4720) use a 5.1 inch wet clutch pack. I'll bet the 5220 (peak torque only around 130?) has significantly more clutch area and a tranny capable of more torque input.)
On the hydro on the other hand - there is power loss in the coversion of mechanical to fluid to mechanical energy (the hydro pump and motor) that will bleed some torque off - and the ability to set a relief valve to a point that the hydro motor never feeds more power into the rest of the mechanical geartrain than it can handle.
Which would make for a fascinating experiment - (PTO ratings aside) would a 4720 hydro have more actual pull grunt than a reverser 4520 at the rear wheels?
I wonder if due to their power levels these twenty series will ever see a Nebraska test?
Tim
timb
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Just thinking about that before with all my griping on the various 'problems' of the CUTs...
I guess what I would really like is a 90% scale version of a 5220.
That is... 90% of the length, 90% of the width, 90% of the wheelbase - 90% x 90% x 90% of the weight and engine displacement, etc.,.
Actually if you do the math what comes up is almost dead on dimensionally for the 4000 large frame series. Except I also want the engineering approach/function of the 5220. Instead I keep feeling the 4000's are more like half that approach and half a 150% version of a GX335.
Tim
I guess what I would really like is a 90% scale version of a 5220.
That is... 90% of the length, 90% of the width, 90% of the wheelbase - 90% x 90% x 90% of the weight and engine displacement, etc.,.
Actually if you do the math what comes up is almost dead on dimensionally for the 4000 large frame series. Except I also want the engineering approach/function of the 5220. Instead I keep feeling the 4000's are more like half that approach and half a 150% version of a GX335.
Tim
rockyridgefarm
Elite Member
<font color="green"> half a 150% version of a GX335. </font>
75% of a GX?!! /forums/images/graemlins/confused.gif
Just kidding, i undertand... /forums/images/graemlins/grin.gif
75% of a GX?!! /forums/images/graemlins/confused.gif
Just kidding, i undertand... /forums/images/graemlins/grin.gif
OP
Ole_Hickory
Silver Member
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- 175
I would imagine the hydro's in tractors are becoming more and more common with each passing year.Do you think there are more hydros then geared tractors being sold in the compact line of tractors now ?
Good Question I'll bet some of our dealer and manufacturer based members can answer better, but I believe that hydrostatic drives make up the majority of new sales. My first test drive was on a DK40 that had what I believe was Kioti's version of a shuttle shift... name may be wrong, but it was easy to drive. Then I tried a Deere with the Hydro - no clutch, no levers, just backwards and forwards. It's a shame that Kioti didn't have the CK30's out yet to compare to - I would have liked looking at them. I still may go look when they come out just to see their newer products.