Does HP alone influence to the "power" of a tractor?

[PutnamVictor]

Why does a JD L111 ($1.5K) have a 20HP engine and an X700($10K) have a 23HP engine? Both are gasoline. This is more pronounced when you compared an older tractor, 1960's or 1970's to one build in the last decade. It seems that the HP of the engine is not the only factor to the "power" of a tractor. If HP is related to torque via RPM's, what am I missing? What makes a 10HP (1960's) tractor stronger then a 20HP HomeDepot mower?

 

[whistlepig]

Why does a JD L111 ($1.5K) have a 20HP engine and an X700($10K) have a 23HP engine? Both are gasoline. This is more pronounced when you compared an older tractor, 1960's or 1970's to one build in the last decade. It seems that the HP of the engine is not the only factor to the "power" of a tractor. If HP is related to torque via RPM's, what am I missing? What makes a 10HP (1960's) tractor stronger then a 20HP HomeDepot mower?

I think a 10HP motor is a 10HP motor no matter when it was made. HP and torque are related but there is a bit more to it than that. It depends at what RPM the peak HP and torque comes at and how large a range of RPM the engine can carry this peak HP and torque. I understand this but I sure hope someone else explains.

 

[ronmueller]

Take a look at this link, and scroll down to where the relationship of power to torque is explained.

Horsepower - Wikipedia, the free encyclopedia

Think of torque as what makes the wheels and PTO turn on a tractor. You could have two different tractors, both with the same amount of torque, but on runs at twice the rpm as the other. The tractor with twice the rpm would have twice the hp, even though they both have the same torque.

Hope this helps with your question---ronmueller

 

[GPintheMitten]

Well, I'm no expert, but besides horsepower and torque, you have got gearing, hydraulics, traction, weight, ground clearance, size and types of tires, axles, steering mechanisms, 2wd, 4wd.

I've had a very nice 23 horsepower lawn mower before and it was great, but it would not do well at ground engaging chores. But my 15 horsepower Kubota B6200 does pretty well at it.

 

[JoeinTX]

"I've had a very nice 23 horsepower lawn mower before and it was great, but it would not do well at ground engaging chores. But my 15 horsepower Kubota B6200 does pretty well at it..."

Exactly. That's why it's so difficult to "tell" someone what tractor or implement to buy when you can never know exactly what they will use it for.

There are a lot of 35hp compact tractors on the market.......some of them will do a whole lot more than others and it really has little to do with the engine.

 

[manganos]

You can have a 100hp tractor but if it doesn't get traction it isn't worth a crap

 

[radman1]

Why does a JD L111 ($1.5K) have a 20HP engine and an X700($10K) have a 23HP engine? Both are gasoline.

Talked with a JD saleman once about mowers. He said the mowers of the smaller units are basically throw away motors if they have any major issues. The more expensive units are much better built engines. Should last much longer and have less issues. Cheaper motors are air cooled, more expensive are water cooled. Same concept for engines on zero turn mowers.

 

[whistlepig]

Gearing is a huge factor. If you can't match the ground speed and attachment load to the RPM that the motor makes it's best torque and HP you will not get all the power that motor was designed to give. This is one of the best features of HST.

 

[bp fick]

Lots of one upmanship marketing today. People are drawn to ever larger HP stickers. Some of it is necessary, given the parasitic nature of HSTs which dominate today.

The rest is marketing. High RPM ratings to achieve a neater looking, higher HP sticker on the hood. You decide what is what, fact from hyperbole. It's a bit of both.

In the end, a tractor needs torque, weight, big tire traction and gearing to take power to the ground, that is why they are called TRACTors, as in traction. Otherwise, they'd be porta-powers units.

 

[Reg]

(overly) simplistic;
Torque is force, horse power is rate of doing work.

For many/most part timers force is what is most useful, but to apply it to ground engaging implements requires traction and that is achieved by some combination of tractor weight and tire pattern. With low enough gearing.

For a lot of folk here using Cat 1, sub 1 and Cat 0 speed isn't THAT important.
Sure, it would be "nice" to pull a wider rake or rear blade, go faster with a wider rototiller, etc., but small may be slow and at least it is low cost and you get more seat time.

For folk trying to make MONEY horse power comes into play, since it determines not just THAT a plow can be pulled, but HOW MANY bottoms of what width can be pulled at what depth and FAST enough to roll the soil over.
Getting it all DONE in time for planting matters too (-:

Power is force times speed - I forgot to mention that (-: