Why so much HP in a mower?

[invincible569]

Im curious as to why some of these walk behinds and zero turn mowers have 15-25 HP today? Back 15 yrs ago, a 5+ HP machine was sufficient enough to cut down a nice overgrown lawn. 15HP sounds reasonable, but why 20 or 25? Does it really make that much of a difference? I dont feel its a selling point for me unless i was working new jobs daily for clients who never maintained their lawn size. Someone tell me something I dont know or if you agree with what I am seeing.

By the way, i have been reading around and the reason why more HP is available today is because of the new technology advances.

[BCSteel]

Because time is money. The less time that you have to slow down in thick or wet or over grown grass, the faster the job can get done = more $$ in the bank. Efficiency is king and trumps all others.

[invincible569]

BC, I completely forgot about the wet turf. That would definitely make a difference. What Im trying to say is that if you had 2 mowers.. a 15Hp and a 25Hp both equal in size and brand... and lets put your idea into the mix... if it just rained and grass was a little above average... would you use the 25Hp over the 15hp? Would a 25Hp eat more gas?

The reason why i am asking this is because when I make a purchase, I want to make sure if HP would be a selling point or if it would be one the last things on my list.

[BCSteel]

The 25 would almost certainly eat more gas but would you want a 25 on a 36" mower? Probably not. Would you want a 15 on a 60" again, probably not.

When I bought my walker I thought that 16hp was plenty, and it was at first, when I could pick and choose the days that I wanted to work (within reason). But as my company grew and time lines were set almost in stone, 16 hp just wasnt enough to get the job done in other than ideal conditions.

[A+ Lawncare]

can any1 say 31hp..... hehe

[heavenlydeere]

look at it like this , if you had two trucks of the same make and model with the only difference being one had a 4 cyl and the other a 6 cyl , and both
were trucks that ran a route carrying a somewhat heavy load , which do you think would get the better gas mileage? , my money is on the 6 cyl, simply because it has to work less to achive the same results as the 4 cyl ! the same could be said of a 15 hp 54'' ztr and a 25 hp 54 '' ztr of the same make and model cutting 8 '' heavy grass, the 25 hp would most likely be the more efficient of the two ! and also henry ford got around just fine in his model A's
but i think we all like the autos we drive today, with 200 to 300 % more hp than henrys model a , and sometimes more than that! i think that technological advances are ,for the most part, truly a Godsend ! i can remember using 2.5 hp 21 inchers but i sure do like my new 7 hp 21s !

[TRANSMAN]

HORSEPOWER to inch cut ratio

Im curious as to why some of these walk behinds and zero turn mowers have 15-25 HP today? Back 15 yrs ago, a 5+ HP machine was sufficient enough to cut down a nice overgrown lawn. 15HP sounds reasonable, but why 20 or 25? Does it really make that much of a difference? I dont feel its a selling point for me unless i was working new jobs daily for clients who never maintained their lawn size. Someone tell me something I dont know or if you agree with what I am seeing.

By the way, i have been reading around and the reason why more HP is available today is because of the new technology advances.

Back when i was a kid the standard 21 " push mower had the 3.5 Briggs..

21 inch cut divided by the 3.5 H.P equaled each horsepower had 6 inches of grass to cut... 21/3.5= 6 .. 3.5 X 6 =21...

Useing the old standard a 32 inch cut mower would only require 32 divided by 6" = 5.3 hp..

By the Same standard a 60" cut mower divided by 6 would only require 10 hp useing the old standards

The 42" cut would require 42 / 6" =7 hp ..

As we all know today 21 mowers have 5-7 hp engines and wether or not you need it is up to your decision .21 / 7hp=3"

A 21" mower with a 7 hp engine leaves the engine with 1 hp cutting a measly 3 " swath... 7 hp on the 21 sounds high considering 10 yrs ago the 3.5 hp did the job, but also remember if you double the 21" cut to 42 " the size of most lawn tractors the new standard in push mower standards would say the 14 hp engine would be equal overkill on the 42" mower...

Sears started a runaway H.P trend on their crap, by throwing 24 hp engines on 42" decks.

42" deck divided by 24 hp left 1 hp to deal with 1.75 inches of grass...

useing that ridicalas standard a 21" inch pushmower cutting 1.75 " grass pr hp would have a 12 hp engine sitting atop...21" / 1.75" = 12 hp..

12 h.p on a 21" mower would be a little silly in my oppinion, but that is about what the power to cut ratio is with the 24 hp 42" cut lawntractor...Driveing the lawntractor requires very litttle hp with the gear reduction they employ,I.M.Oppinion....

I talked to some big wig engineer at kawasaki once apon a time, and he said sears started running away with excessive hp a few years back to increase sales...He claimed Sears asked for a bid from kawi at low discount prices, and kawi provided them with engines built with cheaper parts and labels stateing H.P numbers that werent really accurate....

I guess everyone jumped on the more hp is better bandwagon following sears, because after all, whos going to spend $9000 for quality brand A, if questionable brand Z "sears' has got more HP, for $6000 less???..

In my oppinion 7 hp on the 21" mower is plenty... 14-17 hp on the 42 -48" should equally be suffecient, and 32 hp should be left to the 100"decks ..

So i would pay more attention to the quality of the hydro`s, chassis construction , and ease of opperation of the unit along with parts availability, and customer support ...

The H.P values seem to be coverred with plenty of reserve and would "NOT" be the decideing factor in a mower purchase...

Sincerely,TRANS

[heavenlydeere]

transman i agree that the deciding factor should not be based solely on hp,the main factors imo should be dealer service, quality of build,cost,and how well the machine works on grass and in your business! i do however think that the less a machine works at doing a specific task then the better the outcome! how many times when you have been mowing,especially a few years back, and thought to yourself, man i wish this had a bigger motor?
ever cut 8'' grass with a 3.5 hp 21''er? how many times did you start it?
my point is this , a 25 doing the same task as a 15 will do it more efficiently!
especially when time is a huge factor and we constantly push our equipment
harder and harder! i do agree, to base a purchase on hp alone is very foolish!!

[GrassMaster]

LOL, as always bigger is Better!

Snapper had a 3.5 hp SP bagger many years ago, it was a good mower but it was in a strain on the least little bit of extra grass. Then they moved up to the 5 hp models, it had a different pulley on it & the SP was faster but when going into thicker grass or mulching with it you had to slow down the travel speed so you could cut the grass...

Now they have 7 hp home owner models, more power less engine strain & definitely cut through thicker grass or mulch grass far faster than a 5 hp.

Many many years ago I had a 48" Yazoo mower with three blades on it with a 18.5 Kohler Twin on it. It could slice centipede grass like hot butter, I mean 8 to 10 mph. People would pull over & watch it cut. I had one of the first Sunstran Hydro's in the area... LOL it had a steering wheel & a foot pedal, the pedal was forward, stop & reverse.

It cut great but when I hit real thick areas of St. Augustine & Bermuda type grass I had to slow it down quite a bit or the engine would bog down thus giving me a bad cut. If I would have spent the extra money & got me that 23 hp I probably wouldn't had to slow it down.

More power more money! YEEEEHA!

[invincible569]

The consensus so far says that it is good to have a nice powerful mower for new clients or existing ones that may suprise you with a tall thick lawn. But all mowers shouldnt be at the latest HP max as you may be throwing away money that you didnt need. Time will tell if you need a new HP tough mower with your clientelle amount and service. Good to know!