Which one will pull more???

[Dutch445]

I would think anytime you increase size of tire, and get
more surface area, along with more weight, you get better
traction.

A lot of this will depend on the ground which the tractors
is pulling on, like others have said. it depends on soil
conditions.

but,

the 11.2 tires is very small, and i have had several
complaints about those tires because the 4310/4410
had the large R-1 option, which isn't available now. Probably
has something to do with the MFWD overrun ratio being
changed with the new 3X20 tractors.

 

[Z-Michigan]

In terms of pure pulling force, weight is #1 factor and tires are #2. If total weights are about the same and both are MFWD, then the R1's should win. In *force*.

Horsepower is a measure of capability to do work, which is basically force times speed. If you're using an implement that can run at higher speeds, the traction may be less of an issue and the one with more engine hp will probably win.

 

[jcmseven]

So, for the sake of discussion, we have these two tractors, a 3520 for example and a 4320 (just randomly chose these two--not specific reason). The 3520 has 71 lb. ft of torque roughly and weighes 2900 pounds dry, but has R1 tires on the front and back. The rear R1's are loaded with Rim Guard at 24 gallons per tire for a total rear ballast of around 500# (slightly less). Let also say this machine has the 110 pound weight kit from JD at 220# additional ballast in the rear, for a total rough tractor weight of 3620#, fully ballasted. The 4320 has about 110 lb. ft of torque at rated speed and weighes 3700# unballasted. It has R4 tires and has ballasted rear tires, holding about 42 gallons per tire for a total ballasted weight of 820# or so in the wheels and 4520# overall. The rough difference in actual weight between these two machines is about 900#. In drawbar pull on, say, dirt or pea gravel (loamy) type soil, which machine is the stronger?? Does the group still favor the heavier machine???

John M

 

[jcmseven]

Also, does horsepower make ANY real difference in drawbar pull in a compact size machine?? Since these machines roughly weigh the same among each size range, does on machine, say a 4520, have an advantage over a 4320 or 4120 in drawbar pull????

John M

 

[orlo]

jcmseven:

Engine torque isn't very significant a measure without knowing gear ratios, etc. It's 'ground force' that is the meaningful number that even if we knew the rear wheel diameters and the rear end ratio (The 4000 series is planetary) would be hard to calculate in the hydro since we'd also need to know the hydro pump force, etc. You could 'roughly' calculate the overall engine to wheel ratio by looking at the top speed in low range but that still wouldn't be that accurate.

Drop the wheel size also and you increase the effective Ground force for any given axle/wheel torque. I.E. If I am getting 8000 ft/lbs of force with a 2' diameter wheel (1 foot radius) I'm getting 8000lbs of ground force. If I increase that wheel size to 4' then I'm getting only half that.

Unfortunately nothing is simple...

 

[RollTideRam]

JCM, you didn't go and make a bet with a neighbor that your tractor (3720) could out pull his tractor (4320) did you? And now you want to know how many wheel weights to add before the showdown? If you did, will you post a video for us? JC

 

[jcmseven]

JC,

No, I did not do so. The real reasoning behind this question is that I am contemptlating going back to a larger machine, as I do a lot of ground engagement work with my machine. There are certainly comprimises with the larger tractor, so if I could approach the ground engagement capacity with my current machine I will keep it instead. I am thinking about going back with R1 tires, currently my machine has the R4 tires also. My dealer says there is no way a mid frame machine can duplicate the pulling and pushing power of a larger 4000 series machine, but I am not so sure about that if the tire and weighting was correct.

John M

 

[Dutch445]

I really wish we still had the larger
R-1 tire option for you.

I have had 2 customer swap out tires,
and rims for the front.
1 went out of spec as far as JD over-run
ratio.. the other one I helped spec out
tires and found a set of tires that would
work, and fit on his back rim.

He up graded to a 12.4-24 from the 11.2,
and used a 16" front.
but, it was a chore to find the combination
of tires that worked within the JD MFWD
overrun spec.


but, after all of this talk, we'd still like to
see that 3720 hooked up to a 4320,
R-1 vs R-4, ballasted vs not.. you may
find if conditions are right, the 3720 wins.
but, i think it all depends on traction.

 

[orlo]

Dutch:

Stupid question, but do dealers have some sort of heavy 'pull scale' (Maybe hydraulic. That they could hook up to a tractor and an anchor and see what type of 'actual' draw bar pull any given tractor could produce (On different surfaces of course). Seems like this would be a useful rating per tires and maybe a few standard surfaces. Maybe even a 'stall' rating if you could get the wheels to not spin but not move if you were on concrete or asphalt.

Maybe I'm just dreaming....

Or maybe JD could test all their tractors with a pull sled like the competitions...

 

[wolc123]

You certainly can maximize the pulling power of a 3000 series with balasting and R1's, but the best you will do is possibly equal a poorly balasted 4000 series with R4's. Certainly there is no way you could aproach the pulling power of a properly balasted 4000 series with R1's. Your machine is simply too small for this challange. Another big advantage of the 4000 series is aprox a 25% increase in hydraulic power and flow. A 4120 is about the same $ as a 3720 but for ground engagement or hydraulic capabilities the difference in these models is huge.