Mowing RPM

85Hokie

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BX-25D ,PTB. Under Armor, '90&'92-B7100HST's, '06 BX1850 FEL
Jul 13, 2013
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Bedford - VA
What RPM should general mowing be at? I mowed at 3000 RPM and it seems to do fine. New tractor BX1870 with 54 deck
This is an age old question with lottttssss of opinions......

bottom line - the blades and all the rest ARE designed to cut at a certain rate to achieve a "normal" cut.

Lots of people cut at a slower rate, thinking they are helping the mower and engine work less......but these ENGINES are designed to run at "X" rpm to do the job well.

And with your 3000 rpms - you are in the money as to where to cut rpm wise.
I think WOT on your machine is something like 3200-3300 rpms, so I would think at your 3000 rpm - you are spinning the blades at the RPM that the deck was designed to do.

I can feel the vibration in my butt when I hit that sweet spot when cutting, and it is up there close to 3000 on my BX too.;):)
 

armylifer

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BX1860, FEL, RCK54P MMM, BB1548 Box Scraper, Quick Hitch, Piranha Bar, BX6315
Mar 26, 2013
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I have the same mower that you do on my BX 1860. I mow most of my yard at around 2800 RPM in low range. I think that mowing at 3000 RPM is good too. The way that I use to judge if I am at the "right RPM" is to look at the grass that I am cutting. If the grass is being "cut" instead of "torn out", I am at the "right RPM".
 

Dr Honda

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BX1870
Mar 30, 2015
174
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Pitt, PA
I also have a BX1870... but with a 48" deck. I run it up to 3000 RPM, and put it in low range. It's the perfect speed with my foot all the way down.

FYI... I run it full throttle when I do leaves. (Better lift, and only a couple hundred RPM more)
 

TripleR

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BX2200, BX2660, L5740 HSTC, M8540HDC and some other tractors and equipment
Sep 16, 2011
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I do all of my mowing at the recommended RPM whether MMM or or RFM or rotary cutter. I know others will differ and I don't get excited if I'm a bit off, but I stay right at the recommended speed.
 

armylifer

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BX1860, FEL, RCK54P MMM, BB1548 Box Scraper, Quick Hitch, Piranha Bar, BX6315
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I do all of my mowing at the recommended RPM whether MMM or or RFM or rotary cutter. I know others will differ and I don't get excited if I'm a bit off, but I stay right at the recommended speed.
The problem with the BX1860 and I think other BX models is that there is no indication of what the PTO speed is at a particular engine RPM. If I knew what speed my PTO was turning I would peg my tach on the correct engine PRM and keep it there.

If anyone knows of a chart that shows what the PTO speed is in relation to engine speed for the BX1800 series, please post it.
 

TripleR

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Sep 16, 2011
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The problem with the BX1860 and I think other BX models is that there is no indication of what the PTO speed is at a particular engine RPM. If I knew what speed my PTO was turning I would peg my tach on the correct engine PRM and keep it there.

If anyone knows of a chart that shows what the PTO speed is in relation to engine speed for the BX1800 series, please post it.
Mine is in my owner's manual in a chart for Mid and Rear.
 

armylifer

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Thank you TripleR, I just found the speeds in my manual under specifications. The MM PTO is turning 2500 RPM at 3043 engine RPM.

The manual for my RCK54P-23BX shows that it is rated up to 2969 RPM at the spindle. The manual does not specify what speed to operate the mower at, just what the maximum rated RPM is.

So I guess the answer to the OPs question is that the engine RPM should be at 3043 RPM to turn the MM PTO at 2500 RPM. I would say that 3000 engine RPM should be sufficient for mowing.
 

85Hokie

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Thank you TripleR, I just found the speeds in my manual under specifications. The MM PTO is turning 2500 RPM at 3043 engine RPM.

The manual for my RCK54P-23BX shows that it is rated up to 2969 RPM at the spindle. The manual does not specify what speed to operate the mower at, just what the maximum rated RPM is.

So I guess the answer to the OPs question is that the engine RPM should be at 3043 RPM to turn the MM PTO at 2500 RPM. I would say that 3000 engine RPM should be sufficient for mowing.

I am gonna give the original poster credit.... he was at 98.586 of the correct speed!:D:eek::)
 

user4211

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Mar 23, 2016
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Crawfordsville,In
I run mine at full throttle. Old machines didn't have a tach, so I think people give too much thought into this stuff. It's a lawn mower with a loader. Hop on it and use it. Go wide open throttle in high gear. Won't hurt a thing.


Sent from my iPhone using Tapatalk
 

ironpony

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B7100
Mar 4, 2016
84
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6
Lancaster Ohio
I was always told on a hydrostat to run it at full RPM so the hydraulic system is working properly, which I assume would run the pto at the rated RPM
On my geared 7100, I run full throttle with the pto lever at the recommended speed
 

xtruckerbob

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Kubota L2600, - BX 2670, - BX 25-D-1, -G3200, - RTV 900, - ZTR 121S
Nov 7, 2012
23
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Winnsboro, Louisiana
We have BX25D and a BX2670 both with 60" mmm decks which mow about 15 to 18 acres a week. We mow at 2700 RPMs . At that speed the engines don't bogged down, and the fuel economy is better, But if we missed a week and the grass was high I would mow at higher RPM if needed. As for speed we mow as fast as the grass will allow.
 

CountryBumkin

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BX2370 w/LA243, Bucket, Grapple, QA Pallet Forks, 60" MMM, rear blade & rake
Sep 27, 2015
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Also, for new owner, the manual says do not operate the tractor at full speed for first 50 hours.

So you should probably mow at the rpm of 2500 - 2750, until the tractor is broken in.

This is assuming that when Kubota says "Full Speed" they are referring to "engine speed" and not road speed (maybe both). At least that's the way I interrupt it.