Do you mow at 540

[JerryG]

540-RPM usage is only a general guideline. The same RPM is not the best for every piece of equipment. Do you think that a Jimi with a FarmPro cutter has the same wear characteristics as a JD with a Frontier cutter? Or a 1960 Allis with a Coop cutter?

 

[Doc_Bob]

You'll also notice that the book qualifies "proper blade speed and produce a clean cut" they do not say that running the mower at less than 540 will be detrimental to your tractor or mower"

Mike, you are such a detail freak !
Good point.
Bob

 

[Soundguy]

The tractor doesn't bog, the clippings are small and scattered, and I have probably cut 6 db from the noise level.

6 db huh? that can be a huge amount of SPL... you really think it cut your sound by a wide factor like that... considering sound is non linear.. etc

Soundguy

 

[Soundguy]

Does your tractor not reach 540 pto rpm untill full throttle? Most of mine hit it at about 2/3 throttle .. etc.

Soundguy

I just don't like hearing an engine running at full throttle unless their is a load on it, again just my opinion - right, wrong or indifferent.

 

[Soundguy]

the 540 light on my tractor. The engine is screaming at that point and don't try to tell me that is good. .

Unless otherwise stated in your manual.. do you have any reason to believe that your tractor won't operate a pto load for extended periods?

Ever seen engines running gensets? Ever see them run continously, 24-7-365... That is very common in many industries. Many even have provisions for oil changes without shutting the unit off.

Soundguy

 

[Soundguy]

With this kind of logic about reducing wear on your tractor etc.. a thought just occoured to me.

Why not leave your tractor parked int he barn 100% of the time and just not use it at all.. that will REALLY reduce the wear on it...

Come on guys.. there are big tough pieces of metal.. made to run in the sun and heat all day.. drinking fuel and get put away wet. If yardwork was so hard on tractors and killing them right an left then you wouldn't see tractors from the 40's still running around working... They had worse metalurgy, and lower technology, and worse lubes... and guess what.. with a little care.. lots of the oldies are still here.. why? because they were built to do the work... Just like our modern tractors are built to do the work...

Soundguy

Greg, I want to stress 1 more point before I quit on this one. The 540rpm "standard" was probably a gentleman's agreement between implement manufacturers and tractor manufacturers so the implements could be rotated within a usable RPM range. I don't think a lot of engineering went into determining 540 RPM. It's not even addressed in any manual I've ever read. It's just a given, like lefty-loosy righty-tighty.

One more point and I promise I'll shut up. Equipment... engines, transmissions, gear boxes, etc. can be run 2 basic ways: To finish the job as fast as possible, or to cause the least wear and tear on the equipment. They are not 1 and the same! As RPM increases, wear and heat increase 2x to 4x more in proportion. Every 100rpm on the PTO probably doubles the heat and quadruples the wear on mower's a gear box. Reducing RPM is guaranteed to increase gear box and transmission life. I worked for years in failure analysis, and believe me, running higher RPM will always decrease component life.

When in doubt, I follow the Mfr's recommendations. When the Mfr's recommendations are missing or ill-explained, I rely on my own experience and "feel", for which there is no substitute.

 

[jeffinsgf]

You'll also notice that the book qualifies "proper blade speed and produce a clean cut" they do not say that running the mower at less than 540 will be detrimental to your tractor or mower"

Like I said, do whatever floats your boat. I think you're splitting hairs that shouldn't be split.

Just to bring in an example from another field that I am much more familiar with. In woodworking, every tool should be run as fast as it can without causing friction burns. With an irregular shaped piece of wood on a lathe, it takes much less effort to cut at 500 rpm than it does at 200 rpm. When I am turning a bowl from a natural edge blank, I always turn the speed up to the point the piece is vibrating the lathe, and then back if off until the vibration settles down. Since my lathe weighs about 900 pounds, even a big out of round blank is probably turning 300+ rpm. If I work on a smaller lathe and have to start at 150 - 200 I can really tell the difference. When the piece is round and balanced, I kick the speed up to 1500 rpm.

A table saw that is turning too slow is much harder to work with, since each tooth is impacting a larger area.

I contend that JD didn't think that they had to ALSO list that running at lower rpm is bad for the equipment. I read "proper" blade speed to mean the best for the machine as well as for the cut.

I guess we'll see in 15 or 20 years. Check back with me then, and we'll see whose mower is in the best shape.

 

[PineRidge]

Guys look I'm not looking for an argument here. We can agree to disagree on this point and still be friends. I only made a comment that 2600RPM/540 PTO speed was a constant for me with the mower until I tried 2000 RPM. The engine raced less, the mower raced less, the grass was cut just as nice, and I used less fuel. How can that be so awful bad?

If you all want to run at PTO speed for mowing it ain't gonna affect those of us that choose to run at less RPM one way or another, it's just a different way of doing things, it still doesn't make us lepers.

 

[have_blue]

it's just a different way of doing things, it still doesn't make us lepers.

By definition efficiency is doing the most with the least power, wear, stress, and in my case noise and vibration. My tractor is not big and tough. It's only 35hp with a 6' brush hog with 55hp rated box. I don't have unlimited funds to fuel it and repair it, and sharpening very dull blades is not a favorite chore. So, I sacrifice about 1mph to go easy on my ears, the seat of my pants, and my wallet. Oh, and I rather mow grass than puree it and leave it in rows of balls. If that makes me a leper, I'll proudly wear a scarlet "L" on my forehead. Ehhhh... make that my ankle. Make that my brush hog.

If the weeds get away from me, or I have brush to mow, I will probably end up mowing at 540 and you guys can have a good laugh at my expense.

 

[Farmwithjunk]

Guys look I'm not looking for an argument here. We can agree to disagree on this point and still be friends. I only made a comment that 2600RPM/540 PTO speed was a constant for me with the mower until I tried 2000 RPM. The engine raced less, the mower raced less, the grass was cut just as nice, and I used less fuel. How can that be so awful bad?

If you all want to run at PTO speed for mowing it ain't gonna affect those of us that choose to run at less RPM one way or another, it's just a different way of doing things, it still doesn't make us lepers.

The entire thread reminds me of a time when I called my cousin to help me with my central air conditioner a few summers back. He works on HVAC full time. I was busy getting hay in, and the Mrs wasn't feeling too good. She was demanding the air be fixed. I called "cuz" over to bail me out.

He spent 5 hours tinkering with everything. I got a call from my wife wanting to know when he was going to have the house cooled down. I asked Taylor (my cuz) how things were going. He said," Well, the head pressure is perfect, The fan is running at the right speed, compressor is running fine, air flow seems to be good, Just about right temperature differential on pressuer and suction lines, looks good to me"!

"But Taylor, is it making cold air"? I asked.

"Well, not as far as I can tell"

Moral of the story? If it works, everything is OK. If it DOESN'T, try something different. No matter how much "by the book" you play it, the only thing that REALLY matters is the end result.

Mow at whatever RPM your heart desires everyone!