Mowing Mowing Speed

[Freds]

I have a G2160 and normally mow just about pedal to the metal, or rubber mat in this case. Sometimes it's floored. If you can handle the bumps and the mowed grass looks OK when you look back, then I'd mow as fast as you want to get done.

 

[keeney]

RE: "...and the mowed grass looks OK when you look back, then I'd mow as fast as you want to get done. "

But the next day when the grass that was merely squished over by the wheels and not cut to correct height recovers, stands up straight again, and is longer than the other grass, it may not look as good as when it was first cut.

I also seem to recall that mowers are limited to a maximum blade tip speed dictated by ANSI safety requirements (at least those marketed for residential use and claiming to adhere to such standards), so there is a maximum speed.

I think the "loft" of the blade may have a lot to do with things as well. A higher loft blade creates more airflow to stand the grass up and clear the clippings, but it requires more power for the same size blade and speed to blow all that air.

- Rick

 

[ThistleKop]

Rick,

<font color="blue"> I also seem to recall that mowers are limited to a maximum blade tip speed dictated by ANSI safety requirements (at least those marketed for residential use and claiming to adhere to such standards), </font>

You're correct Rick. That max blade tip speed is 19000fpm as indicated by another poster. It is more than a optional std. CPSC insists upon it!

TK

 

[keeney]

19,000 FPM may seem really fast, but some arithmetic can put things into perspective as to why 10 MPH is pretty fast for mowing:

19,000 FPM tip speed on a 20" dia. blade is just a hair over 3600 RPM.

10 MPH is 880 feet per minute.

3600/880 is less than 4.2 revolutions of the blade per foot of travel.

You have both ends of the blade, and you cut on the front and back side of the deck, so thats 4 cuts per revolution, or 16.5 cuts per foot of travel (through the center-line of the deck to keep things simple).

Each cut is 12/16.5" or close to 3/4 of an inch apart.

Only the end 3 inches or so of the blade does the cutting, so 3 / (12/16.5) = just over 4 cuts on average for each blade of grass.

At 5 MPH instead of 10, you have twice as many revs per foot of travel or about 8 whacks at each blade of grass. At 2.5 MPH (walk-behind speeds), you are double that again, or 16 whacks at each blade of grass.

Things get worse with larger diameter blades because to stay at the same maximum FPM at the tip, the RPM has to go down.

- Rick

 

[GerardC]

</font><font color="blue" class="small">( Mowing speed is directly proportional to the length of the wifes honey do list. The longer the list, the slower the tractor goes. )</font>

LMAO! Gerard

 

[keeney]

RE: Mowing speed is directly proportional to the length of the wifes honey do list. The longer the list, the slower the tractor goes.

What about when mowing is ON the list?

- Rick

 

[Soundguy]

</font><font color="blue" class="small">( You have both ends of the blade, and you cut on the front and back side of the deck, so thats 4 cuts per revolution, or 16.5 cuts per foot of travel (through the center-line of the deck to keep things simple).

Each cut is 12/16.5" or close to 3/4 of an inch apart.

Only the end 3 inches or so of the blade does the cutting, so 3 / (12/16.5) = just over 4 cuts on average for each blade of grass.
)</font>

Regaurdless of how it may loo to you on paper.. I can tell you.. I mow at 10mph.. and there ain't nothing left to stand back up the next day that the mower runs over. I mow 10ac of my pasture every month.. I chop it off at 4" to 6" or so.

That's 5th gear on my tractor ( 1st and high ) and that was the recomended speed to cut with as told to me by the NH dealer.. In fact.. that was the selling point.. I wanted a machine I could cut fast with. I've seen other largeish tractors cut at that speed as well.

I'd guess 'what' you are cutting may have a little to do with it. Soft lush grass that can't support it's own weight and is already laying over may be an issue. Stemmy stuff, black tops.. weeds, etc cut just fine on my property.

Soundguy

 

[keeney]

RE: "I'd guess 'what' you are cutting may have a little to do with it. Soft lush grass that can't support it's own weight and is already laying over may be an issue. Stemmy stuff, black tops.. weeds, etc cut just fine on my property."

Yes, I was thinking lush lawn/park vs. pasture cutting.

Sufficient power and blade loft can improve things at higher speeds

- Rick

 

[Dargo]

Since my Kubota L5030HSTC has a digital speedometer in the dash, I can say that, depending upon the conditions, I mow at speeds from anywhere from 4.3 mph to about 11 mph. The slow area is due to the terrain being less than smooth. Perhaps with a good kidney belt I could mow it faster, but it wouldn't be fun. The performance of the cut seems to be the same independent of the speed I'd travelled. Of course, if I am trying to cut 10" off of the grass, I'd have to slow down or it would suffer. /forums/images/graemlins/blush.gif

 

[Soundguy]

</font><font color="blue" class="small">( Of course, if I am trying to cut 10" off of the grass, I'd have to slow down or it would suffer )</font>

I'd agree with that. Straight tall soft grasses seem to be the most difficult to cut well.. both due to height and coarseness of the plant.

I've found that plain old 'brush' is the easiest to cut. Bramble.. tall stemmy weeds like dog fennel and ragweed, etc. Pretty much as fast as you can safely drive through them you can cut them. When i bought my pasture it was about 7' tall.. but cut easier than my neighbors overgrown lawn that was 3' grass.

Soundguy