kubota vs. kioti

[k0ua]

Let me phrase it this way:

For pulling heavy loads, (or any load for that matter), engine torque dont mean squat. Final drive torque is what matters. And that is easily changed (by design) with gearing.

My little 100hp saturn has a bigger motor and higher torque rating than my kubota. So why does my kubota do better towing a heavy load???

Answer: Gearing has made it so the kubota has more torque to the wheels.

But if you had to tow a 1000lb trailer down the road at 60MPH, which one would you choose? It does amaze me how tiny our tractor engines are, and how little horsepower they have, but how much we can shove and pull with them. But wow, are they ever geared down.

 

[MtnViewRanch]

Something that you guys are not considering is the amount of time that the engine will put out the power that they are claimed to have. It's called duty cycle. Nothing that I know of that goes down the road and this includes all of the new semis, they all have less than a 100% duty cycle. I am pretty sure that most if not all of the tractors small and large have a 100% duty cycle. Dragsters come to mind, thousands of HP, I have no idea what torque range, good for what, a few seconds. Great if you need to get a 1/4 mile in 4 seconds, not good for much else.

Just my :2cents:

 

[94BULLITT]

Yes, but if one wheel loses traction the other will not pull.

Right.

 

[SPYDERLK]

you have twice the pull of the wheel with the least traction.

Ditto.

 

[LD1]

But if you had to tow a 1000lb trailer down the road at 60MPH, which one would you choose? It does amaze me how tiny our tractor engines are, and how little horsepower they have, but how much we can shove and pull with them. But wow, are they ever geared down.

Well, since roads in my area are pretty bumpy, and the kubota's got not suspension, the saturn wins by default. And yes, they are geared WAY down.
Figuring its slowest geat at WOT, a rear tire may only make 5 or 6 revolutions a minute. With the engine running 2800-2900, somewhere approaching 500:1 gearing. While gearing in a typical p/u may only be ~12:1 overall. Roughly double that if you have 4wd and put it in low.

Something that you guys are not considering is the amount of time that the engine will put out the power that they are claimed to have. It's called duty cycle. Nothing that I know of that goes down the road and this includes all of the new semis, they all have less than a 100% duty cycle. I am pretty sure that most if not all of the tractors small and large have a 100% duty cycle. Dragsters come to mind, thousands of HP, I have no idea what torque range, good for what, a few seconds. Great if you need to get a 1/4 mile in 4 seconds, not good for much else.

Just my :2cents:

IT is something that I consider. But didnt really have a bearing on the argument of HP vs Torque and what is more important. I understand perfectally clear that while my saturn is rated at 100hp, under normal driving, I dont come anywhere close to using all of it. More like 20-30 hp. And if I did have to use all 100 ponies all the time, the engine would fail rather quickly. Whereas my tractor gets used much closer to 100% of rated power for most of its life.

 

[GManBart]

The tundra has the ability to pull heavy objects better. Cause the tundra can be geared to give the exact same torque to the wheels. And have almost double the HP to help crest steep hills at more than a crawl.

No matter how you gear it, the mack aint gonna have any more power.

Horsepower is the amount of work that CAN be done over a given period of time. The tundra is capable of MORE work in a given time. OR it can do the same work as the mack only quicker.

Torque at the engine is irrelevant. Cause it can be changed with gearing to suit whatever needed torque you require.

LMAO. You have no idea what you're talking about. A Toyota Tundra can pull more weight than a cement mixer can? That's got to be the silliest statement I've ever seen here. A cement mixer grosses out at around 80K lbs when loaded with 10yds of concrete (yes, that is over legal weight limits). How well would my Tundra pull a total of 80K up a big hill? It probably couldn't do it at all, and if it could, it would be barely moving.

Horsepower is a very poor measure for rating engines, and in fact, is not a legal measure in many countries.

So, your theory is that torque doesn't matter. Okay, I have a simple test for that theory, and you're not going to be able to argue it....sorry in advance.

Take a steam locomotive back in the day. It's at a dead stop. The boiler is fired up, and everything is ready to go. They open the valve to get under way....the pistons aren't turning for that first instant. The engine is making exactly ZERO horsepower (pistons have to move to produce horsepower). How does the train start moving? If it has zero horsepower, how can it move hundreds of tons of weight? How can this be?

The answer is that while the engine is making zero (or very nearly zero until it gets up to full rpm) horsepower, it's making many thousands of ft/lbs of torque.

 

[TSO]

LMAO. You have no idea what you're talking about. A Toyota Tundra can pull more weight than a cement mixer can? That's got to be the silliest statement I've ever seen here. A cement mixer grosses out at around 80K lbs when loaded with 10yds of concrete (yes, that is over legal weight limits). How well would my Tundra pull a total of 80K up a big hill? It probably couldn't do it at all, and if it could, it would be barely moving.

Horsepower is a very poor measure for rating engines, and in fact, is not a legal measure in many countries.

So, your theory is that torque doesn't matter. Okay, I have a simple test for that theory, and you're not going to be able to argue it....sorry in advance.

Take a steam locomotive back in the day. It's at a dead stop. The boiler is fired up, and everything is ready to go. They open the valve to get under way....the pistons aren't turning for that first instant. The engine is making exactly ZERO horsepower (pistons have to move to produce horsepower). How does the train start moving? If it has zero horsepower, how can it move hundreds of tons of weight? How can this be?

The answer is that while the engine is making zero (or very nearly zero until it gets up to full rpm) horsepower, it's making many thousands of ft/lbs of torque.

That sounds right...

If I've got a seized nut/bolt, and I'm trying to get it turning from a dead stop, I have to apply torque. If I don't have enough torque to move it, I go grab a breaker bar to increase my torque. Torque is the amount of force I can exert to manipulate a non moving object.

Once I get it un-seized, then I use my horsepower to keep spinning it free at the higher speeds. Since I can only spin it so fast, the breaker bar does not increase my personal horsepower... And if a spot on the threads becomes tight again, its not horsepower that powers me through it, the resistance is met again with my torque to power through it until it loosened up again and my horsepower carries me through.

That's how I look at torque & horsepower anyhow...

 

[GManBart]

Let me phrase it this way:

For pulling heavy loads, (or any load for that matter), engine torque dont mean squat. Final drive torque is what matters. And that is easily changed (by design) with gearing.

My little 100hp saturn has a bigger motor and higher torque rating than my kubota. So why does my kubota do better towing a heavy load???

Answer: Gearing has made it so the kubota has more torque to the wheels.

Completely apples-to-oranges.

Compare identical vehicles, with the same transmission/gearing, and engines with different engine hp/torque ratings, and see what happens.

Take a new Ram 1500 with the 3.6L Pentastar engine that has 305hp and 269lb/ft of torque...it's rated for 7,450lbs of towing capacity.

Take the same truck with the 3.0L Ecodiesel V6 engine that has 240hp and 420lb/ft of torque....it's rated for 9,200lbs of towing capacity.

Wait, the one with less horsepower, and more torque, is rated to pull a heavier load???? Shocking, shocking I say!

 

[arlen4720]

Horse Power is a function of RPM and torque. An engine that produces boat loads of torque at a low RPM would be making "X" amount horsepower. A different engine all wound out producing very little torque might also be producing the same "X" amount of horsepower. In either case, you would need to use gearing to get the right speed/torque that you require for the application.
An engine with a nice flat torque curve is nice because you are relying less on the transmission. Think of an engine with little torque for pulling, you would be always be shifting and likely need many more gear choices. One reason why diesels are better for such applications....nice flat torque curves.
One reason why tractors need so many gears is because we need to maintain the engine RPM to get the PTO speed, so we need allot of gears to to get the proper ground speed.
Certainly torque means allot in practical applications.
From a purely theoretical standpoint (which doesn't mean squat), gearboxes can be used to swap speed for torque. Power IN= Power Out (minus losses).
I don't think I would like it too much if I had to keep my tractor at 10,000 RPM like a Japanese motorcycle, then have 100 gears to get me where I wanted to go on the output.

 

[LD1]

Yes the tundra engine would pull the weight up the hill, and be able to maintain a faster speed doing so, If (and this if seems to be the part you keep missing)....

If it is geared to produce the same final drive torque.

Again, you can get whatever torque you want with gearing. But HP don't change.

Why aren't electric motors sold by torque?

Because you can use pullies, sprockets, and gearboxes to get whatever torque you want.

A 1 HP motor running through a 100:1 gear reducer will make more torque than a 50hp motor at 1:1. But obviously the 50hp motor will do more work, even though its output is less torque than the 1hp w/gearbox.