Why are tractors so under-powered?

[redshirt]

Please go tell Kenworth, Petebilt, Freighterliner, Volvo, that their doing it all wrong, their trucks won't run 5,000 to 6,000 miles a week in a team situation. I think they will tell you they can, will, and have done it for years.

 

[LD1]

Please go tell Kenworth, Petebilt, Freighterliner, Volvo, that their doing it all wrong, their trucks won't run 5,000 to 6,000 miles a week in a team situation. I think they will tell you they can, will, and have done it for years.

Maybe I missed it somewhere......but I didnt see anybody make the claim that they are doing it wrong

 

[k0ua]

I think that's because the OP already pointed out in the original post that the torque per liter (in addition to hp per liter) is also much lower in tractor applications than pick-up trucks.

- HP / torque characteristics are chosen based on a tractors weight and intended use
- engine is chosen that can reliably deliver HP/torque required by tractors weight and intended use
- Marketers then sell several models with slight bumps up in HP and charge big premiums for them because "everyone wants the best".

Interesting to note, that what is considered over powered vrs underpowered is often debated on TBN. Except people usually call overpowered tractors underweight! It all depends on the application. If you want to mow big fields and run the largest mower possible HP is important. If you want to push over a tree, gearing, weight, and torque are important.

This reminds me of a video I did once. My friend had a Toyota Echo (108hp) and thought it would out pull my 19hp tractor due to the superior hp. No chance. Anyway, watch the video if you'd like. Jeep Rubicon vs 19 hp tractor is also on there. It shows that for many tractor tasks, hp doesn't matter. (but for field work, more hp means more speed less time with same implement - I get that)

Kioti LB1914 vs. Toyota Echo and Jeep Wrangler (Tractor Pulling) - YouTube

And that was pulling against a pretty small tractor. It might be interesting to see what the Ford 250 would do against your DS4510HS. A closer match for sure.

 

[k0ua]

Just in case it's not clear, there are really two different questions being answered here. I actually don't know which the OP meant to ask.

Question 1 is why tractor engines are rated for so much lowered HP per liter of displacement compared to pickup diesels. The answer has to do with duty cycle for the engine in its application.

Question 2 is why don't our tractors have more horsepower than they do. The answer comes down to traction, and the max size implement the tractor can handle and its horsepower requirements.

In my experience snow blowers and field mowers are the only things that really put a load on the tractor engine. For any kind of pushing or pulling the wheels will spin before the engine bogs down. A snow blower is the only thing I've used that can seriously bog down a tractor.

One other application is spinning an electrical generator. You can run out of HP easily there and be wishing for much much more if the generator isn't sized correctly.

 

[Btown]

And that was pulling against a pretty small tractor. It might be interesting to see what the Ford 250 would do against your DS4510HS. A closer match for sure.

The tractor has the advantage in this due to being on dirt. Those tires have better treads than both the car and Jeep. Do this on asphalt and I bet there will be a much different result.

 

[LD1]

My truck is something like 315hp/625 ft lbs and 7900#

My tractor is 51hp and about 1000# lighter.

I like the tractors chances in a tug-of-war on any surface condition including pavement

 

[gladehound]

The tractor has the advantage in this due to being on dirt. Those tires have better treads than both the car and Jeep. Do this on asphalt and I bet there will be a much different result.

hmmm.... let's see - the car did have chains on. But back to the question. What would happen on asphalt.

I predict lot more smoke from the car - tire smoke or transmission smoke, maybe a little of both. Or maybe something on the car would outright break. But one thing is certain, there is no surface on which that ~2000 pound car would out pull a 3800 pound tractor, even if it only has 19hp!

however, I do predict that the Jeep, weighing 600 pounds more and having lockers on both axles would out pull the "3 wheel drive" tractor on asphalt.

 

[gladehound]

And that was pulling against a pretty small tractor. It might be interesting to see what the Ford 250 would do against your DS4510HS. A closer match for sure.

Sold the F250 before getting the DS4510HS. Weight is very similar, close enough that I don't know which is heavier. No doubt the DS4510HS would pull the F250 on any surface. The F250 had a worn out limited slip rear diff which i.e. functioned like an open diff. The front diff also did not lock. The tires on the truck were a harder rubber as well. Don't think the F-250 would have much of a chance.

 

[gladehound]

My truck is something like 315hp/625 ft lbs and 7900#

My tractor is 51hp and about 1000# lighter.

I like the tractors chances in a tug-of-war on any surface condition including pavement

LD1, just noticed the MX in your profile. Nice upgrade! I guess I'm a little late the to party on that one!

 

[LD1]

LD1, just noticed the MX in your profile. Nice upgrade! I guess I'm a little late the to party on that one!

Yea, a little late

Made the upgrade earlier this year in the spring. April or May sometime?