Old vs. New models:Torque comparisons

   / Old vs. New models:Torque comparisons #1  

73jeep

Silver Member
Joined
Mar 28, 2005
Messages
181
Location
NC
Tractor
Massey Ferguson 1523
I was wondering how the current CUTs or even subCUTs compare with older vintage tractors in torque. For example, an old International 140 or Allis Chalmers CA with 26-27 PTO HP; do they have a lot more torque than a modern CUT with equal HP?
My new tractor is a MF 1523 gear which has 18.7 PTO HP.(Max. torque is 50 ft. lb). Does an old MF 135 (with just a little over twice the PTO HP) only pull a little over twice as much, or will it pull 3 to 4 times as much?(with loaded tires my weight is also half the weight)
It seems that those older tractors with much bigger displacements would have more torque than equally horsepowered smaller tractors today. I just don't have any data as to how much torque those older tractors had. Any info.?
 
   / Old vs. New models:Torque comparisons #2  
The MF 135 with a Perkins diesel has 38 engine hp, 33 PTO hp with 121.7 ft-lbs torque @ 1300 RPMs. This isn’t from an official MF publication, so I don’t know how accurate it is.
 
   / Old vs. New models:Torque comparisons #4  
It's easy to figure *some* of this out from the hp/rpm rating numbers, since torque, hp, and rpm are all intertwined with a simple formula.

Torque = (hp * 5400) / rpm

So - your MF 1523 with it's 68.5 cu in engine has a maximum engine hp of 22.5 hp @ 2600 rpm. That means it's torque output at that same rpm is around 47 lb-ft of torque.

An old IH130 (don't have 140 numbers with me) with it's 'big' 123 cu in engine had around 23 engine hp @ 1400 rpm - or around 89 lb-ft of torque.

That sounds great for the old IH - however - it takes gear reduction to put that crank RPM to the PTO - or on the ground. If both tractors run the PTO at the same speed (540) or had the same size tires and the same ground speed - the modern MF has to have a lot more gear reduction happening than the old IH. Gear reduction=torque multiplication, so the same torque (more or less) is at the PTO or at the ground in both cases.

The other difference though is the peak torque number (and the rpm that it occurs at) that's your seat-of-the-pants lugging abiility - and that info is much harder to come by.
 
   / Old vs. New models:Torque comparisons #5  
You need to be more specific...

How exactly do you want to measure said torque?

It's a tough question... torque/HP are pretty meaningless by themselves... the efficiency with how you actually get that power to the ground and/or to the load is what is important.

I suppose this is why tractor pulling competitions exist... they elimate all the BS between whatever numbers say and reality... it's the whole package that matters, not just the number at the crank.
 
   / Old vs. New models:Torque comparisons
  • Thread Starter
#6  
<font color="blue"> </font> "I suppose this is why tractor pulling competitions exist... they elimate all the BS between whatever numbers say and reality... it's the whole package that matters, not just the number at the crank." <font color="blue"> </font> <font color="black"> </font> Ok then, next question........
My Mom and Dad have an Allis Chalmers "B" which has 19 PTO HP and weighs roughly 2000 lbs. If I take my 1523 with approx. 19 PTO HP and roughly 2000 lbs.(filled rear tires) and have a tractor pull between them...who'd win? Would their "B" pull more because its HP is rated at a lower rpm, or would my 1523 pull more because of lower gearing (6-spd vs. 3-spd) and the fact I have 4WD?
....and by the way, thanks for everyone's input.
 
   / Old vs. New models:Torque comparisons #7  
I once read the actual Nebraska tests on some comparative tractors and was surprised by the figures that they came up with. Some tractors would develop more horsepower than another brand, but the second brand would develop more pounds of pull at the drawbar-- go figure! /forums/images/graemlins/confused.gif /forums/images/graemlins/confused.gif. I don't know if the University of Nebraska still conducts these tests or not; but they used to be the standard by which the industry went.
 
   / Old vs. New models:Torque comparisons #9  
Tie 'em together and gun 'em. Wear a hard hat and post pics.
 
   / Old vs. New models:Torque comparisons #10  
You need to have the same tires and the same surface to compare properly. Tractor "A" might win on Monday in field X, while tractor "B" would win on Tuesday in field Y. There are too many variables involved -- soil type, soil moisture, soil compaction, plant cover, tire circumference, size of contact patch, tread depth, tread angle, radial or bias ply, long bar/long bar or long bar/short bar, straight bar or curved bar, tire pressure, weight distribution on the tractor, etc. etc. Plus the CUT will have 4 wheel drive most of the time, while the older Ag machinery won't.

Just worry about whether it does the work you want it to do.
 
 
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