John Deere 3720 vs. 4120

ArtVandelay · Jun 27, 2007

I am trying to decide which size tractor would be better for 9 acres of pasture that I have to mow. I get a lot of tall reed canary grass on the land (if it's not mowed regularly) and that grass can grow up 6 feet tall and 1/2 inch thick. IMO, anything less than 35 PTO hp and a 5ft bush hog would be too weak to do the job in a reasonable amount of time. I am thinking about going with a 5ft bush hog instead of a 6ft because the 5ft would be more powerful at 35 PTO hp.

I will also be tilling about 1/2 an acre, and possibly be removing a few small tree stumps occasionally.

I know some people may say a Kubota B3030 would be fine, but IMO that is ridiculously weak unless I wanna spend 10 hours mowing each time. I am not someone who likes to buy the absolute minimum equipment that I would need. I think that a little too much power is better than not enough power.

I was thinking about the JD 990 too, but I would rather have something a little nicer and more comfortable.

Since the cost difference between the two tractors (3720 vs. 4120) is not very much, is it worth it to get the 4120? Will the 4120 make deeper rutts in the ground, or will it's wider tires prevent that?

Thanks.

Keith_B · Jun 27, 2007

I wouldn't think the weight differences be significant enough to make purchasing the 3720 an advantage. Given the type of heavy duty mowing you plan to do I would move up a to a 4320 or 5205.

Greyfields · Jun 27, 2007

I would go with the 4120 simply because you'll have more hydraulic lifting capacity. Also, the wheelbase on the 4x20 series is right at 6'. Running a 5' mower could be awkward, since you'll have to overlap your last pass more than usual.

I have a lot of reed canary grass here, as well as tussock. I mow at about 3.5 mph when I'm going through tall stuff (with a 6' rotary cutter). Occassionally, the turbo kicks in a bit, but it won't even slow you down.

ArtVandelay · Jun 27, 2007

I think the minimum I could get by with is the JD 3320 with FEL and LX-5 rotary cutter. The ideal setup would be a JD 4120 with FEL and LX-6 rotary cutter.

jcmseven · Jun 29, 2007

Art,

Having had both two 3720's and a 4520 and, sadly, too many other JD's to count at this point, I would say go 4120. I went smaller again because for my locale my 4520 was simply too large to fit some places I needed. For my currently the 3720 is perfect in size. For you though I think you would find the 4000 series machine to be more stable and ride better over rough terrain, such as the type mowing you mention. It has plenty of power as the PowerTech engine has a lot of torque. The 3720 is a hoss, though, and would easily run a large RC or RFM without straining. I have pulled a 7' behind mine before and it did not notice it, even in really deep grass. I suspect the 4120 would be similar. I understand Keith's point, but in my opinion, the upgrade in power from a 4120 to a 4320 is not enough to really do. My neighbor has a 4320 and I have operated a 4120 before, although I have never owned one. I could tell zero difference between them, although I will say I had limited seat time on the 4120 I had. If you are looking for more power than the 4120, I suggest the go-for-broke 4720. It is a monster and would power any cutter over anything at anytime without any problem.

John M

jcmseven · Jun 29, 2007

In my previous post, I did not mean to imply that I "sadly" owned John Deeres, just that I am sad I did not get to keep them all!!!!!

John M

ArtVandelay · Jun 29, 2007

Thanks for the responses everyone.

Kyle_in_Tex · Jun 29, 2007

I think the 3320-3720 would do you fine for most tasks. The 4120 does not take that much more room to turn, if you need to do heavier tasks, it would be more stable and powerful hydraulics. The turbos on either frame will give you MUCH more "grunt"/torque. The 3320 has no turbo.

BTW, does ArtVandelay import or export?

ArtVandelay · Jun 29, 2007

Kyle_in_Tex said:
I think the 3320-3720 would do you fine for most tasks. The 4120 does not take that much more room to turn, if you need to do heavier tasks, it would be more stable and powerful hydraulics. The turbos on either frame will give you MUCH more "grunt"/torque. The 3320 has no turbo.

BTW, does ArtVandelay import or export?

ArtVandelay is an importer/exporter

kozak · Jun 30, 2007

Glad to see that your deciding on a more capable machine.

Just like you said, anything below 35 PTO HP would be too weak & why risk going too small when you know you have a relatively large task you want to do that won't take you all week.

From a rutts perspective, 2900 lbs versus 3700 lbs makes the 3720 the clear winner. 800 additional pounds in the right circumstances....well.....you will sink deeper. Now from a ground engaging standpoint or doing FEL work & other tasks, more weight is a good thing. So you will have to balance & weigh

the trade-offs.

The only advantage I see in the 4120 is a smoother running machine (4 cyl.)& a little more torque & hydraulic lift. For your task this would seem to be the clear winner as you will be riding that tractor for hours at a time.

Both machines have pretty much the same capabilities. From an operator fatigue standpoint I think you would be happier with the 4120 & if the price difference is not that great the 4120 would be an incredible tractor to own & operate.

Keep us posted with whatever you decide.

Good Luck,

Vic

wolc123 · Jun 30, 2007

In most of the hydraulic categories (pump flow, loader lift weight, 3 pt lift weight, loader lift height) The 3720 does around 75% or less than the 4120 (note that the 4120 does the same as the 4720 in these areas). That is not what I would call "nearly the same capabilities". I would call that a BIG difference in favor of the 4120. That will make the difference in safely handleing a round bale on a loader mounted bale spear, or loading a tandem dump truck. These big jobs are beyond the 3720's limits but can be safely done with the 4120. The 3720's smaller size is an advantage in tight places or if you need to trailer with small equipment. Without these constraints, the 4120 wins, no contest.

radman1 · Jun 30, 2007

The 4x20 series does have a louder engine than the 3x20 series. It is quite noticable but may not be a concern to you. Listen to both.

kozak · Jul 2, 2007

wolc123 said:
In most of the hydraulic categories (pump flow, loader lift weight, 3 pt lift weight, loader lift height) The 3720 does around 75% or less than the 4120 (note that the 4120 does the same as the 4720 in these areas). That is not what I would call "nearly the same capabilities". I would call that a BIG difference in favor of the 4120. That will make the difference in safely handleing a round bale on a loader mounted bale spear, or loading a tandem dump truck. These big jobs are beyond the 3720's limits but can be safely done with the 4120. The 3720's smaller size is an advantage in tight places or if you need to trailer with small equipment. Without these constraints, the 4120 wins, no contest.

ok.....OK....I stand corrected. Looking at the specs again there is quite a difference between the 3720 & 4120. I guess I should not have used the word "nearly". Initially, did not look at loaders specs. The 400CX loader definitely out performs the 300CX. For cutting high grass I believe the 3720 can handle the task but definitely the 4120 will do it much easier. So again, the 4120 would be my pick.

Vic

Greyfields · Jul 2, 2007

And I'll repeat myself that if I did it all over, I'd go 4320 instead of 4120. There are all kinds of 40 HP PTO implements out there, whereas down to the 35 HP things get scarce.

MuttonPower · Jul 3, 2007

I agree with you all. My 4120 customers can accomplish a lot more than my 3720. Namely lifting heavier objects, pulling wider mowers, wider tillers, bigger disks, grader boxes. All the while experiencing a better ride. for around $19000 it sure is a lot of Tractor. J Dalman

matthew3120 · Jul 5, 2007

Hi all,

I just traded my 3120 w/300X loader and bought a JD 4120 with 400X loader and 2072 boxblade and just in my veiw the 4120 makes my 3120 look and feel like a toy. but don't get me wrong but the 3120 was grear but go with the 4120

Matthew3120

jcmseven · Jul 6, 2007

Matt,

Are you going to change your handle to Matt4120 now?? Indeed, the large frames are LARGE. It is sometimes difficult to realize without actually bringing one to the property just how much larger they really are. Congratulations on your new machine!!!!

John M

AKfish · Jul 6, 2007

Yes Sir --- Matt. Congrats! Fill us in on your impressions and "work" accomplishments with your new machine in the coming weeks.

A picture is darn near like running the controls yerself.... so, let us see yur new beauty!

Akfish