3720 Finish (Pull Behind) Mower - How big is too Big?

[shortthrow50]

The weight of the mower is 1500lbs., the 3 point is rated:

Lift Capacity (24-in. behind link arms), lb. (kg) 2200 (999)
Lift Capacity @ lift link ends, lb. (kg) 2530 (1149)

Will it lift it no problem?

looks like you answered your own question

 

[RoyJackson]

looks like you answered your own question

I think he did too...but he would have a problem with no front ballast (loader or suitcase weights).

 

[eagle107]

I think he did too...but he would have a problem with no front ballast (loader or suitcase weights).

I agree. You will need a front ballast for that mower.

Also, even at a minimum 30HP PTO, that is a big mower especially when you hit grass at 2, 3 or more inches above the cutting height of the mower. PTO HP is not the only thing to look for when using an implement with your tractor, you also have to know how much torque your engine can produce to the PTO. The 3720 is a good powerful tractor, but the tractor will strain when hitting the heavier grass (depending on how high and thick it is). You might be better off with a 84" or 72" mower instead. If you really need a 100+" mower, then you might want to consider a tractor with a 4 cylinder engine, such as the JD 4120 that can produce more torque to the PTO.

 

[Rockgod]

well i have a 72 inch mid mount mower on my 3520 and its just a couple horses less than yours and it bogs down in grass thats been let go for 2 weeks. This is in "B" range at about 6.5 mph with the air conditioner going. I originally wanted a non turbo 3320 and im glad i went with the turbo 3520. heres some quick video of it bogging down a little in said grass. You will have to go in creeper gear real slow and take a long time i would imagine with that size rear mower
3520 john deere 72" mmm - YouTube

That is what I call mowing in style! How much lawn do you cut?

 

[RoyJackson]

well i have a 72 inch mid mount mower on my 3520 and its just a couple horses less than yours and it bogs down in grass thats been let go for 2 weeks. This is in "B" range at about 6.5 mph with the air conditioner going. I originally wanted a non turbo 3320 and im glad i went with the turbo 3520. heres some quick video of it bogging down a little in said grass. You will have to go in creeper gear real slow and take a long time i would imagine with that size rear mower
3520 john deere 72" mmm - YouTube

I'm quite surprised you're having any problems. My 4400 (just about the same PTO HP as your 3520) with a 72" mower doesn't even breath hard in thicker, taller grass.

 

[jenkinsph]

I'm getting an 3720 Cab.

I mow about 5-10 acres of fields/paths and around buildings and a a 2100x100' grass runway.

I'm looking at the GM2109 110" Frontier mower. 30HP minimum required

Way too big? Will it bog down in anything over an inch or two or will it be fine cutting 5-6"'s if it's dry?

I have an MX6 in case it gets really long.

Thanks

Sounds a lttle large for a 3720 imo, both the MX6 and the GM2109 are heavy mowers. I assume you want a setup that will mow the open areas quickly and that you are trying to save some time with the wider mower.

I will make another assumption that the runway is smooth and in this case you could operate at a higher ground speed to save time.

I would recommend going with the 72" mmm and a light weight setup for the tractor, you should be able to mow at a higher ground speed with less compaction. Time and fuel costs would be about the same. If you want an rfm then I would consider a 72" to 84" that is much lighter than the GM2109 at 1500 lbs. Keep in mind that a tractor rated for 35 pto hp is not going to make that much power while traveling across the field, more like 20 to 25 hp to the deck and the rest to moving the machine and powering the ac on a cab tractor.

Others here are more familiar with the 3x20 machines than I am but an auto connect mmm deck would make attaching and detaching easier I believe.

 

[GeorgeC]

I'm quite surprised you're having any problems. My 4400 (just about the same PTO HP as your 3520) with a 72" mower doesn't even breath hard in thicker, taller grass.

My 4300 was the worst for bogging down. THE worst..

I hated that tractor for being so weak with a 72" deck, so my next purchase was the 3720. Problem totally and completely solved.
I can't find grass tall enough to move the RPM needle the tiniest bit. It's the belt on the mower that takes the beating, and usually needs changing every other year.
I just took delivery of my new 3720. What a pleasant surprise to see the turning radius a whole lot tighter than my 2005 3720.

 

[eagle107]

morrisond,

I think Steve (jenkinsph) and I are right. If you are going to use the implements from your 5425 such as the 90" slowblower and purchase a 110" finishing mower, then you should go with the 4000 series tractor. The JD PowerTech engines in these tractors will give you the torque you need for these implements, plus the tractor will give you a longer and wider platform to wield these implements.

Which 4000 series is up to you or what your dealer thinks; a good dealer will steer you in the right direction. I think you can get away with a 4120 or 4320, but if do not want to worry about having enough PTO power, then go with the 4520 or 4720 like Steve and I have.

You can also use the standard rule of thumb that many TBN members use which is 5PH at the PTO per implement foot. Your finishing mower would be ~9 foot which would indicate you need 45HP at the PTO and the snowblower is ~7.5 foot equally 37.5HP needed at the PTO. Personally, I think these numbers are high for a finishing mower and snowblower, unless you are hitting some very heavy stuff. Remember that 30HP or 35HP at the PTO on 3000 series tractor and a 4000 series tractor is quite different in terms of toque/power(work); the 4000 will be more powerful at the PTO with the same PTO HP rating. Good Luck with your tractor shopping; that is always a fun time!

 

[sjhulsmn]

I run a Landpride RFM3590 90" finishing mower behind my cab 3720. I'd have to look at the mower specs, but I'd guess it weighs lust under 1,000 pounds. My 6 acre lawn is flat and smooth. My tractor handles the mower with no problem mowing in B range between 4 to 5 mph. I would not want any bigger mower behind the 3720 both for pulling that weight, maneuverability and also for scalping issues with that solid deck.

 

[Piston]

Have you considered a gang real mower? I would think with a nicely groomed runway it would be an ideal mower for your smaller tractor.