Traction Traction To Use The HorsePower

[bp fick]

The B series and the BXs, like most tractors, have steadily increased in horsepower over the years. It seems that every spring, the Apron stores roll out lawn mowers with ever increasing HP ratings, enticing customers with 24, then 26, then 28 horse power models. With this HP creep, the question arises:

Can that HP be effectively transferred to the wheels? A BX, in its present incarnation, is limited to 12 inch rear wheels and 10 inch front wheels max and is mounted on 1300 lbs on average overall weight.

Question. Is there a limit to HP creep? Can a lawnmower have 34 HP? Can a BX handle 34 HP? Can a B use 40 or 42 HP? What improvements in the HST or in tire science will be required, if any?

Just wondering out loud.

 

[dex3361]

The B series and the BXs, like most tractors, have steadily increased in horsepower over the years. It seems that every spring, the Apron stores roll out lawn mowers with ever increasing HP ratings, enticing customers with 24, then 26, then 28 horse power models. With this HP creep, the question arises:

Can that HP be effectively transferred to the wheels? A BX, in its present incarnation, is limited to 12 inch rear wheels and 10 inch front wheels max and is mounted on 1300 lbs on average overall weight.

Question. Is there a limit to HP creep? Can a lawnmower have 34 HP? Can a BX handle 34 HP? Can a B use 40 or 42 HP? What improvements in the HST or in tire science will be required, if any?

Just wondering out loud.

Yea I hear where you are coming from I am thinking of adding dual wheels on the rear of my Kubota BX1500 to make sure the HP gets to the ground and I think 350# of rear weight and 250# of front weight no make that 200# I don't want to hurt the front axle. To use all of that traction I am going to add a turbo to increase the HP I may add an inter-cooler, turn up the pressure in the injector pump and swap out the injectors I figure I may be able to increase the HP 25%. Let see I am starting with 15HP increasing by 25% that would make it about 18.75 HP hmmmm maybe I should rethink this. Ill get back to y'all about this. Ill use the L4400 while I think this thing over.

 

[Baby Grand]

To use all of that traction I am going to add a turbo to increase the HP I may add an inter-cooler, turn up the pressure in the injector pump and swap out the injectors I figure I may be able to increase the HP 25%. Let see I am starting with 15HP increasing by 25% that would make it about 18.75 HP hmmmm maybe I should rethink this.

Add water injection and you'll be pushing 18.9!

 

[art]

The traction can be a problem if a tractor is unbalanced at any horsepower. On the ag or larger tractors we sell they have charts that give us the best or optimum set-ups. On the compacts it's drawing on our knowledge to give the best. I've found that to start light and with good reasoning depending on circumstances makes a big difference in performance over just the load them up to the max and let them go and work.

Just to throw weight at something doesn't mean it will cure a high horsepower to weight traction issue.

Many of the lawn mowers have needed higher horsepower to over come the electric PTO clutches for safety. They normally need an extra five horsepower just for starting as they are a high draw vs just mowing.

 

[bp fick]

I guess my wonderment-amazement was the upward creep of HP generally.

The L model began at something like 15 HP and now offers 50?
The B models began at almost single digit HP and now 30?
As those models grew physically and swelled in HP, the BX was introduced back at the level where it all began.
The BX also began around 10 HP and is now knocking on the door of 28?

Over at TractorData.com there is a history of the Kubota. It is interesting to run your mouse over the models and watch a HP rating pop up.

TractorData.com - Kubota tractors sorted by model

 

[FullBucket]

I have a BX2350 and was pleased to find that my house insurance covered tractors up to 25 HP without need for any additional insurance. I have heard other posters say they had similar coverage. I'm wondering if this horsepower creep will outpace basic covereage and add new costs for more recent buyers. Just a thought to add to the mix.

 

[easygo]

I actually found one particular situation where I ran out of power vs traction. I was scooping gravel with the FEL. I have loaded R4's and I had #550 or so ballast on the 3PH. It was on very firm dry dirt with clumps of dead grass. I was in the process of lifting gravel and pushing the loader into the pile at the same time. Tractor was in 4wd and I had such great traction that the transmission could not turn the wheels. It is hard to describe but I did manage to find the limitations to all of the 21HP of my tractor.
I guess the loaded tires weigh around 300-400 lbs plus I had the #550 ballast and the loader was pretty close to full adding roughly another #600 of weight on the front tires. The dry weight of tractor and loader together is about #1600, so I nearly doubled that and ran out of power.
Not so bad for a little machine I would say.

 

[EE_Bota]

I think you ran up against the pressure relief instead. I suppose if you choked the tractor, you ran out of torque.

One advantage to the increased horsepower is that generally the more residual horsepower you have, the longer the engine will last relative to a smaller engine working flat out. This comes up right much in aircraft engines, but should be true in nearly all situations. Your economy may be lower, the the longevity should be higher.

As for the 5 hp for the clutch..I am not sure I understand. If we assume 50% efficiency of the generator system, we are still taking over 1500W into the clutch coil. That is quite a lot of heat. It seems like the insulation structure would break down. Perhaps I am neglecting something.

 

[Raw Dodge]

I like the extra HP for the PTO as well as the tractor. You can run larger mowers,generators,blowers,and tillers without laboring the engine to the max.The thing is the extra hp needs to come with a larger radiator,trans,pto setup to handle it all.I wish my 1910 sized tractor(or slightly bigger) had 60hp so i could run a 12ft pulle behind batwing mower,and a larger leaf blower for fall cleanup.Its plenty big and heavy enough to handle both,but doesnt have the power to run either.

 

[easygo]

I think you ran up against the pressure relief instead. I suppose if you choked the tractor, you ran out of torque.

I guess you might be right about the pressure relief because the engine RPM didn't change much and certainly didn't choke. However. This was the first and only time, when I had enough traction to stop the wheels from turning. It was just about ideal condition. With the same kind of work on different soil condition I just spin the tires.