Tractor weight vs. fuel consumption while mowing?

[RoyJackson]

I find it hard to accept that added weight does not affect performance to some extent, but find it easy to believe the difference could be so small as to be inconsequential.

That key word is inconsequential...
Add "Dependent upon usage"...

To a trucker or trucking company, a 2%-3% increase in mileage is serious money...to a farmer, maybe (although Farmwithjunk really provided the best response there).

To a CUT owner/operator, we're talking, at most, 10-20 bucks for the entire mowing season (or more). JDgreen227 mows 4.5 acres...even if he mows weekly, doubt he'd save 10 bucks for the season...

 

[Farmwithjunk]

That key word is inconsequential...
Add "Dependent upon usage"...

To a trucker or trucking company, a 2%-3% increase in mileage is serious money...to a farmer, maybe (although Farmwithjunk really provided the best response there).

To a CUT owner/operator, we're talking, at most, 10-20 bucks for the entire mowing season (or more). JDgreen227 mows 4.5 acres...even if he mows weekly, doubt he'd save 10 bucks for the season...

Thank ya Roy!

As is the case with MOST things in life, we tend to "over engineer"/over think issues such as this. There are PLENTY of ways to cut fuel consumption through operator technique, efficient use of time, and properly matching mower (size) to tractor. The "human factor" being the greatest variable, there is where your savings and/or loss is most apt to show up.

JMHO, YMMV

 

[TripleR]

That key word is inconsequential...
Add "Dependent upon usage"...

To a trucker or trucking company, a 2%-3% increase in mileage is serious money...to a farmer, maybe (although Farmwithjunk really provided the best response there).

To a CUT owner/operator, we're talking, at most, 10-20 bucks for the entire mowing season (or more). JDgreen227 mows 4.5 acres...even if he mows weekly, doubt he'd save 10 bucks for the season...

Actually Roy, "Dependent upon usage" is inherent in "could be" in my post. I have spent too many hours on the witness stand to box myself in.

 

[RoyJackson]

Actually Roy, "Dependent upon usage" is inherent in "could be" in my post. I have spent too many hours on the witness stand to box myself in.

Spoken like a true Legal Beagle (or is it Eagle??? I forget)

But...do you know what the definition of "is" is?

I have spent too many hours on the witness stand to box myself in

Was that as the defendant? You could have pleaded the 5th!

 

[dodge man]

I'll chip in here. I own a BX2350, and take the loader off for a lot of reasons listed, but mostly the tractor feels better when mowing with all the weight off the front end.

I also agree that it probably makes almost no difference in fuel used. On my BX, mowing uses more fuel than anything else. You can tell it works the engine a little bit just to spin the blades, let alone going through thick grass. My point is, most of the engergy is used spinning the blades through the grass. If you mowed a lot of hills on really soft ground, I could see it taking more fuel, otherwise, not much difference. Probably the best thing you can do to reduce fuel usage if to sharpen your blades often.

 

[DAY]

Roy's right; perspective is important.
For example, NASA had to transport a piece of equipment earlier today, and during the first few minutes of the trip they burned 11,000 pounds of fuel- every second!

 

[Farmwithjunk]

Roy's right; perspective is important.
For example, NASA had to transport a piece of equipment earlier today, and during the first few minutes of the trip they burned 11,000 pounds of fuel- every second!

What size mower do you suppose that thing'll pull!?!?!?!?!?

 

[backdoor]

I apologize to the OP for this useless info, but since NASA has been mentioned already, I thought some of you guys might get a kick out of this: Space Shuttle Main Engine.

If that link doesn't work, go to Space Shuttle Main Engine Incredible Facts.

 

[TripleR]

Spoken like a true Legal Beagle (or is it Eagle??? I forget)

But...do you know what the definition of "is" is?



Was that as the defendant? You could have pleaded the 5th!

Well, it all depends on the context, theoretical, practical, legal...:laughing:

Nope never as a defendant, but we won't get into that.:laughing:

 

[SPYDERLK]

Extra weight/mass only makes a difference on fuel economy during acceleration. There isn't a whole lot of that going on during mowing of large areas, so it probably won't make any noticeable difference. Also at the speeds we're talking about wind resistance isn't much of a factor either.

xtn

PS - Okay I know weight/mass also makes a difference on fuel mileage when changing the elevation of the weight/mass. But presumably when mowing you're going to shut down in the same place you started up. So you've gone down exactly as many hills as you've gone up, in effect neutralizing any difference weight/mass would have caused.

If you truly had flat, level ground the whole way... If you had the same rolling friction (might require a lot higher air pressure in the tires of the heavier unit, and makes assumptions about axle bearing loads, etc.)... Then it shouldn't make any difference.

It would take more energy to get the heavier unit rolling. But that unit would coast further at the end of the run giving back the energy lost in the beginning. Maintaining a constant speed only requires matching the energy lost to friction. That's regardless of weight/mass.

xtn

Lots of variables as we all don't use the same size equipment or mow the same type materials and on different terrain/soil types/etc. The tractor operator can tell what his equipment is doing. A engineer woud be clueless.

OK...I own and operate a commercial mowing business. We mow (among other things) highway right-of-ways. As part of the fleet, I have 3 IDENTICAL John Deere 6430's. They all 3 pull 15' Bush Hog batwing mowers. One 6430 is used occasionally at my farm or my sons farm. That tractor has cast weights, and a loader (only the subframe stays on while mowing). The other 2 DON'T..... Long story short, that tractor packs 1880lbs more than the other 2 6430's while doing the EXACT SAME JOB.

They all three use (within drops) the same amount of fuel in an 8 hour day. So.....from the hard evidence I have, and "theories" be damned, there is no measurable difference in fuel economy while mowing with any REASONABLE amount of weight added/subtracted from a tractor.

I had two identically equipped Camrys that got different mileage.

... There seems to be something akin to " " addressed at engineers almost by default. I applaud the [seemingly dismissed] contributions of xtn to this thread. Whether he is an Engineer, Physicist, or just somebody who has understood and connected pertinent facts cohesively is not evident in his bio - but is in his posts. The fact that he is correct in theory is not assailable when you have the background to see why the counterargumentsexamples are just RealWorldVariations or sometimes matters of scale that appear huge but arent really much. On the latter for instance:

To determine if there is different energy requirements by weight, push a tractor that weighs 100 lbs. 5 miles on level ground. Now push a tractor that weighs 5,000 lbs. over that same trail of level ground. I think I know which one would make my tongue hang out but I'm no enjineer.

A man cant put out much power long [~1/4 for a while - more for an althlete]. The 1st push takes almost zero; the 2nd about 1/4. A quarter hp for an hour is less than $0.05 worth of electricity ... This huge perceived difference is not much in tractor terms and altho it is absolutely real, it just wouldnt show up above the RWV unless you were using measurement sensors in key areas. Theory often simplifies a problem by stipulating that theres no friction or that there is a specific friction - equal in the compared cases. There is always friction when something moves against another. In a rolling element bearing there is no motion of one against another - every contact point is stationary were the parts meet. So no friction right? ... almost true. The thing that foils absolute truth is that InTheRealWorld every contact deforms the materials in proportion to the load they bear. So the contact is never a zero dimension line or point, but instead is a flattened area where some sliding occurs. That is a friction loss, but due to the ridgidity of the parts is a very low number. -- Another friction loss happens inside the materials in contact. Even tho all the deformation we are talking about is elastic it still always takes more energy to cause the deformation than is given back as the load is removed. In a rolling element, be it bearing or tire, each position on the item exuberantly resists deforming to form the contact area and then springs back rather lackadaisically to a round contour as it leaves it. Even on a flat level surface this [hysteresis] gives the effect of running uphill. Increased tire pressure helps. -- -- So, what if things didnt deflect? No motion&No friction in rolling elements. What is the most efficient surface contact transport we have? Steel on steel. The more rigid [and smooth] the material the better.

The RWV we encounter on our tractors are much greater. Aside from differences inside identical equipment there are different operator habits, tires& pressures, ground conditions, and amount and type of weight. Leaving tracks in ground is an identical additive effect to hysteresis. More weight deeper tracks. AGs may increase rolling difficulty more than others on firm ground [where that tread is the only one that penetrates] as weight is added. Fluid filled tires will roll harder than iron weighted due to pumping losses as well as hysteresis. With the spectrum of variables the anecdotes will cover the whole range. In the strict sense weight will always be a factor. It just wont often be a major one.
larry

 

[RoyJackson]

... There seems to be something akin to " " addressed at engineers almost by default.

Not so much that anyone is rolling their eyes...just that there's a lot of theory being bandied about that just doesn't have much application in the real world of TBN and compact tractor use.
Everyone agrees (and I read most of the posts, but not all) that more weight will require more fuel...pretty much common sense there, I'd say.
In the real world of running our little tractors (addressing CUTs here), there isn't that much savings. We're getting into the realm of dimishing returns.
Doubt anyone who has posted here has the equipment to accurately measure fuel consumption (and you know as well as I do, the tractor's fuel gages aren't precise).

Critiquing SandburRanch's post...why? His methods may not be scientific, but the theory is sound (not practical, but sound). And just as sound as any other theories...and just as practical in the real world of TBN and compact tractor use.

We're not in a lab here, Larry...just a bunch of guys (and maybe some women) kicking around the question that removing the loader may save some money. That question has been settled, I think. And I don't think you'd buy a Big Mac with the savings...

As you may recall from another thread, one of the best courses I ever attended was Technical Writing. One of the primary things to consider is knowing the proficiency of the enduser of the manuals, procedures and presentations...or, as the instructor put it "Know your audience". That's something, that in my experience, technical people tend to forget.

ADDED: BTW, just because I responded to Larry's (SPYDERLK) post implies no criticism toward him or his posts or anyone elses' posts/responses to this thread. Typical of internet forums, we tend to overanalyze some relatively simple common sense topics...

 

[JDgreen227]

That key word is inconsequential...
Add "Dependent upon usage"...

To a trucker or trucking company, a 2%-3% increase in mileage is serious money...to a farmer, maybe (although Farmwithjunk really provided the best response there).

To a CUT owner/operator, we're talking, at most, 10-20 bucks for the entire mowing season (or more). JDgreen227 mows 4.5 acres...even if he mows weekly, doubt he'd save 10 bucks for the season...

Roy, might be a bit late to bring this up, but so far this month (the last 29 days) I have put 23 hours of mowing on my tractor. I have measured an actual 15 inches of rainfall here this month. If I only had to mow WEEKLY, I would be so happy, especially with diesel staying at $4.30 a gallon here. At a gallon per hour, that is just under $100 spent for diesel fuel. At that rate of consumption any savings by removing the FEL will add up fast.

 

[RoyJackson]

Roy, might be a bit late to bring this up, but so far this month (the last 29 days) I have put 23 hours of mowing on my tractor. I have measured an actual 15 inches of rainfall here this month. If I only had to mow WEEKLY, I would be so happy, especially with diesel staying at $4.30 a gallon here. At a gallon per hour, that is just under $100 spent for diesel fuel. At that rate of consumption any savings by removing the FEL will add up fast.

Then pull the loader off and post what improvement you see over the next month or two...

 

[TripleR]

Not so much that anyone is rolling their eyes...just that there's a lot of theory being bandied about that just doesn't have much application in the real world of TBN and compact tractor use.
Everyone agrees (and I read most of the posts, but not all) that more weight will require more fuel...pretty much common sense there, I'd say.
In the real world of running our little tractors (addressing CUTs here), there isn't that much savings. We're getting into the realm of dimishing returns.
Doubt anyone who has posted here has the equipment to accurately measure fuel consumption (and you know as well as I do, the tractor's fuel gages aren't precise).

Critiquing SandburRanch's post...why? His methods may not be scientific, but the theory is sound (not practical, but sound). And just as sound as any other theories...and just as practical in the real world of TBN and compact tractor use.

We're not in a lab here, Larry...just a bunch of guys (and maybe some women) kicking around the question that removing the loader may save some money. That question has been settled, I think. And I don't think you'd buy a Big Mac with the savings...

As you may recall from another thread, one of the best courses I ever attended was Technical Writing. One of the primary things to consider is knowing the proficiency of the enduser of the manuals, procedures and presentations...or, as the instructor put it "Know your audience". That's something, that in my experience, technical people tend to forget.

ADDED: BTW, just because I responded to Larry's (SPYDERLK) post implies no criticism toward him or his posts or anyone elses' posts/responses to this thread. Typical of internet forums, we tend to overanalyze some relatively simple common sense topics...

I had missed this somehow, but could not agree more.

 

[SPYDERLK]

Not so much that anyone is rolling their eyes...just that there's a lot of theory being bandied about that just doesn't have much application in the real world of TBN and compact tractor use.
Everyone agrees (and I read most of the posts, but not all) that more weight will require more fuel...pretty much common sense there, I'd say.
In the real world of running our little tractors (addressing CUTs here), there isn't that much savings. We're getting into the realm of dimishing returns.
Doubt anyone who has posted here has the equipment to accurately measure fuel consumption (and you know as well as I do, the tractor's fuel gages aren't precise).

Critiquing SandburRanch's post...why? His methods may not be scientific, but the theory is sound (not practical, but sound). And just as sound as any other theories...and just as practical in the real world of TBN and compact tractor use.

We're not in a lab here, Larry...just a bunch of guys (and maybe some women) kicking around the question that removing the loader may save some money. That question has been settled, I think. And I don't think you'd buy a Big Mac with the savings...

As you may recall from another thread, one of the best courses I ever attended was Technical Writing. One of the primary things to consider is knowing the proficiency of the enduser of the manuals, procedures and presentations...or, as the instructor put it "Know your audience". That's something, that in my experience, technical people tend to forget.

ADDED: BTW, just because I responded to Larry's (SPYDERLK) post implies no criticism toward him or his posts or anyone elses' posts/responses to this thread. Typical of internet forums, we tend to overanalyze some relatively simple common sense topics...

I had missed this somehow, but could not agree more.

Thanks for the clarification. Reminds me of the woman on Mad TV.
larry

 

[DAY]

We're not in a lab here, Larry...just a bunch of guys (and maybe some women) kicking around the question

-besides, can't dance, and it's too wet to plow. . .

 

[Don87]

Then pull the loader off and post what improvement you see over the next month or two...

But depending on location, and amount of rainfall, the results may be skewed slightly. With less rainfall(which is typical in summer months) the grass being mowed will become thinner due to less rainfall, thus creating an easier mowing situation requiring less power to accomplish the same task, which will in turn cause less fuel usage.

And to answer the tractor trailer question:

With an empty 53 foot dry van, on level ground, i can expect to see near 10MPG on my 60 series Detroit.

With a full load, weighing 80,000 lbs., I can expect to see 7 to 7.5 mpg.
But, this also depends on wind direction and speed. If i'm fighting a 30mph headwind with the full load, I can expect as low as 5 to 5.5 mpg. If it's a tailwind, I can expect 8 to 8.5mpg with the same load.

Throw in a few hills, like I68 in Md/Wv. or I80 in Pa., I can easily drop to near 4mpg(or less with a strong headwind).

 

[RoyJackson]

But depending on location, and amount of rainfall, the results may be skewed slightly...

Yeah, there are a number of variables that we cannot quantify...best we can do (at home) is get a ballpark estimate.

 

[TripleR]

My old boss often used the phrase "gagging on gnats", for some reason that comes back to me now.

 

[JDgreen227]

But depending on location, and amount of rainfall, the results may be skewed slightly. With less rainfall(which is typical in summer months) the grass being mowed will become thinner due to less rainfall, thus creating an easier mowing situation requiring less power to accomplish the same task, which will in turn cause less fuel usage.

And to answer the tractor trailer question:

With an empty 53 foot dry van, on level ground, i can expect to see near 10MPG on my 60 series Detroit.

With a full load, weighing 80,000 lbs., I can expect to see 7 to 7.5 mpg.
But, this also depends on wind direction and speed. If i'm fighting a 30mph headwind with the full load, I can expect as low as 5 to 5.5 mpg. If it's a tailwind, I can expect 8 to 8.5mpg with the same load.

Throw in a few hills, like I68 in Md/Wv. or I80 in Pa., I can easily drop to near 4mpg(or less with a strong headwind).

4 mpg with diesel selling for $4 a gallon....a dollar a mile for fuel expense...I honestly don't know how the owner/operators can manage to continue that for long. I should feel guilty about bitching to Roy about spending $100 for diesel fuel to mow for 31 days....

Lets see now, a ten hour day, average 60 mph, 4 mpg, at $4 per gallon....that would exceed my yearly TOTAL spent for gas and diesel in 2010 (I'm retired) so I better siddown and shuttup.