Ballast 7 foot bushhog with 4120

[msmud]

Folks,
I am new to forum and have enjoyed reading it for quite a while. Need to make a decision about buying a tractor for bushhogging about 40 acres of my 100 acres of varied terrain. Have used and serviced my mother's 3320 cab model and 970 OS model for years so have some experience. She uses the 3320 with a 5' model to bushhog about 40 of HER 100 acres--requires 50 - 60 hours per year for two complete cuttings. Looks like I can get a Cab 3320 with frontier 2072 6 foot light duty for nearly same price as Open Station 4120 with Woods Brush Bull 7' model.
My questions are these: although I am reasonably convinced the 4120 will power the 35 hp requirement of the Brushbull, I am worried about ballasting this monster. Do any of you have experience with a 7' hog on a 4120? How much more weight up-front do you think it will take compared with what Deere lists for the MX6? My mom's 970 has no ballast up front and will raise the front end with just a little provocation. Have some years experience with poor ballasting therefore and am trying to avoid this.
Thanks, TIM

 

[sunnyside360]

Power wise I think the 4120 can handle the 7 footer on the 3 ph but may have a problem with being too light on the tractor front. You may have to add weights to the front or install FEL to hold the front down. I have a 6 footer on a 4320 and it gets a little tipsy on the front w/o the FEL installed, especially on hills.

 

[radman1]

The 7' Woods brush bull weighs 1280#. The JD mx6 weighs 944# and the mx7 1130#. The Woods is fair amount of weight hanging off the back. You should be able to lift the Woods with the JD 4120 which is rated for 2400# lift 24" behind the 3 pt. If you get a FEL, then you will have the ballast for the front. If not, then you are looking at some front weights. Might need 400-500 lbs of weights. The 4120 is relatively short tractor and not much front end weight. I would not try to get the front end too heavy, since much of the mower weight is on the tail wheel when mowing.

You should be ok on the pto hp unless the grass is tall or really thick, even then you just go slower. For 40 acres I would try to go with the 7' model. Personally, I would use my 15' batwing mower.

 

[AKfish]

I think you're gettin' more Hog than the tractor can eat!!

I'd be lookin' at more pto hp at the very least - the 4120 will be at the "ragged edge" of capability and if the grass is real heavy and/or a wet - the tractor will be working real hard to maintain rpm.

Bigger tractor or smaller mower...

If you can maintain a faster, consistent speed with say - MX6 - how much time would you really save crawling around with your front wheels "light" and your rpm's "challanged" using the 7' Woods??

AKfish

 

[trook]

I have a 4320 with a MX-6. I think a 1,100 lb "tail" on the 4120 will be too heavy for that tractor except for optimum conditions and only if you are using a FEL. I would stay with the 6ft. Anything larger and I would want a pull-behind.

 

[RoyJackson]

If you don't have to transport too far or on a paved road, you could disconnect the top link and "tow" that cutter.
In fact, for 40 acres, you might want to consider an 8'-10' pull behind cutter.

 

[radman1]

If you don't have to transport too far or on a paved road, you could disconnect the top link and "tow" that cutter.
In fact, for 40 acres, you might want to consider an 8'-10' pull behind cutter.

That is an excellent alternative but he will need more hp for the 8-10' pull cutter.

A peice of 3/8" chain makes a great toplink for a rotary cutter and is my preference. Allows the mower to float much more freely and easier on the tail wheel.

 

[jenkinsph]

If you don't have to transport too far or on a paved road, you could disconnect the top link and "tow" that cutter.
In fact, for 40 acres, you might want to consider an 8'-10' pull behind cutter.

Pretty much my thoughts too. Especially if you are keeping the 3320 and a 5ft 3pt hitch model for tight spots. I prefer the pull type mower for extended periods of use and feel ( to me) that the cut is better too.


I use an MX6 on a 4520 cab with 6) 70lb front weights with no problems Deere calls for 12) 70lb weights as I recall. I have tried out an MX7 on a 4720 cab which had the 12 front weights, seemed to handle fine and plenty of power to cut thick and fast. I wound up buying the 4520 instead for other reasons.

 

[RoyJackson]

That is an excellent alternative but he will need more hp for the 8-10' pull cutter.

I know pull types require less PTO HP then 3PH type cutters, but I don't know if he'd have enough with 35 PTO HP. That's something msmud can investigate, if he so desires.

 

[eepete]

On-line spec sheet for MX6 shows a weight of 1041 pounds. So a 1280# cuter will be OK for the 4000 series frame. I have the extra ten weight bracket on my 4520. I run 6 70# and 4 42# (total ballast = 588#) and that works OK with the MX6. As Steve said, the manual calls for 12 70# (840#) weights for the MX6 if using a iMatch quick hitch. It "only" needs 10 (700#) for bare 3 PT hitch. Steve saw a 12 weight bracket for the 4000 series frame.

Just for grins, I ran with MX6 42# weights and at some slopes had trouble with front steering. I also ran with no weights, only works going straight downhill :laughing:.

So a big guess here is that with 10 70# weights the MX7 or 7' cutter should be OK if the cut area is not too challenging, based on the weight of the cutters and the performance of my ballasting with the MX6. Getting the 12 weight holder would insure success if they were all 70# weights. That's my answer to your ballasting question.

As for HP, my gut feel and guessing here, but I think the 4120 would be underpowered at 35 HP at the PTO with a 7 foot cutter (hydro version of 4120). I've run my MX6 with 32 HP PTO (via the E-PTO option) and it just barely works, it would bog down in any medium to heavy cutting. The MX6 shows a minimum HP of 30. The MX7 shows a minimum HP of 50 HP. You'd have to look up the minimum for the Woods cuter. I think the minimum is a "if you can" but if you're buying new I'd want to be more in the mid range of HP for the cutter than the minimum. You're on the edge here, so you'll have to factor in slope and density of the grass which is something only you can do.

Lots of number tossed around here :confused2:, hope this makes sense.

Pete