Deck size per Horsepower-Is there a standard

[tractorbeast 27]

Is their a standard for HP per deck size. I've heard some chat about a 48" deck with a twin 17HP Kohler, with it depending on slope of land also. This was with a hydro-trans. What about with a manual trans, could you use the 48" deck with a 12HP 8 speed trans. thanks

[876wheelhorse 46]

i know alot of people on here dont like green. But i mow with a john deere 210 its a 10 hp and i have a 47 inch deck mows no problems. i even pull a 900 pound roller no problems mowing.

[tunahead72 2,518]

Quick answer for now, at least for the 1980's era manual transmission models that I'm most familiar with -- there may be some exceptions, but Wheel Horse generally only offered the 48" deck on tractors with at least a 12HP engine. That particular combination seems to work fine, and there's even those who say that 10HP is enough to drive a 48" deck -- I'm not one of them, just based on my experience over the years with two Kohler 10HP engines with 42" decks.

[leeave96 488]

i've read 1 hp for every 3 inches and also 1 hp for every 4 inches of cut. One way to think about it is - how much hp is required for a 21 inch push mower? Back in the day, an old Snapper mower would have 3.5 hp engine on it. 42 inches would be 7 hp. On the other hand, I've got an IH Cub Cadet with a tired 10hp engine and it runs the heck out of a 44 inch deck and it's hydro. Speaking of hydro's vs gear drive, I've read that you need to allow 3 hp for hydro loss right off the top. I've ran a 14hp Sears Suburban gear drive with 48 inch deck in high grass (when the tractor was near new) and could stall the engine. My 520H will smoke the belts on a 48 inch deck and never stalls - it's 20 hp.

My view is you can use a 48 inch deck on a 12 hp Wheelhorse. My preference would be a 42 inch deck, but you don't have to take a full cut with the 48 either.

Good luck,

Bill

[Kelly 1,030]

I'll throw my 2 cents in the hat, but it is about the same as above, a 12hp tractor in good running cond. will run a 48" deck, hydro or stick, BUT you can not expect it to do a good job if you let the grass get to tall, or the blades get dull, a 42" deck is best suited for the 10 and 12hp tractors, my brother used a 42" deck on a C-81 (8hp) and it did ok if he mowed often, if the grass got to tall he could only take half bites with the deck.

[groundhog47 347]

Tractorbeast

I ain't much for readin' manuals, but figure someone pretty knowledegable wouldn't put their rep on line if not correct. Try >Files>Implements...>attachment...file by Tap53. I'd fig if didn't find a match/size it wasn't "engineer" recomended. But these guys here above have already proved what seems to work. Just tryin' to help!

[Wheel-N-It 2,971]

Is their a standard for HP per deck size. I've heard some chat about a 48" deck with a twin 17HP Kohler, with it depending on slope of land also. This was with a hydro-trans. What about with a manual trans, could you use the 48" deck with a 12HP 8 speed trans. thanks

I have a 48inch deck on a 17hp series 2 Kohler hydro, and also a 12hp 8speed. Never had a problem with either. Yesterday with the 17 I was cutting grass that was higher than the top of the hood. I had to rough cut it once, then go over it again for a finished cut, but again no problem. I would not normally do that but I knew there was no hidden rocks or anything else destructive that I could run over and damage the blades, and I did not feel like attaching the bush hog to my big tractor.

[KC9KAS 4,744]

As stated above, the "lay-of-the-land", sharpness of the blades, condition of the engine, and height of the grass make a lot of difference in what hp one needs for any given size of mower.

[GlenPettit 1,717]

The first 4 or 5 hp is needed to move the (C-series) tractor with you on it, on a typical flat lawn;

the rest of the hp can then go to the deck for mowing.

And, everything KC9KAS said above, about conditions.

With everything in your favor, a 'like new' 12hp can easily handle the 48" deck, but, be prepared for reality . . .

In my opinion, Sharp Blades make a very big difference, as does wet vs dry grass..

[decksetter 50]

+1 on the condition of the engine making a big difference.

That said, my dad's 416H only has 90psi compression in the front cylinder and 60psi in the rear cylinder, and it still doesn't have trouble with the 48" deck. Just can't go too fast through the thick stuff.

[c161rat 185]

I am running a 48" deck on my C-145 8 speed. I regularly sharpen my blades and sometimes find myself having to shift into 1st gear in taller grass. I can usually cut most of my yard in 2nd gear except for a few areas. I also have a rear discharge 42" deck and could cut through taller grass without slowing down however the time I save by having 4 more inches far outweighs the few passes I have to do in 1st gear. So I think the question is bigger better has been answered. At least in my situation Bigger is better!!!!! I was going to go further on this however I will let someone else get in trouble.....LOL!!!!!!

[Don1977 604]

I bought a 1977 C-120 new with a 48" deck it did good but would open the governors in heavy grass. Then I put a 16 HP Vanguard on and I hardly ever open the governors, it would only open the governors in tall heavy grass. I would say a 48" base works best with 16 HP or more.

[RJR49 129]

I had a 10 HP 3 speed. with a 36" deck. Worked great on a flat lawn. A C101 (8 Sp) Worked great but I had to down shift on a fairly steep hill (42: deck.) A C121 8 sp didn't need to down shift on the same hill but I did slow down in deep grass. My C160 Hydro does it all without breaking a sweat.

[Jim Turner 42]

On 11/6/2012 at 8:25 AM, Don1977 said:

I bought a 1977 C-120 new with a 48" deck it did good but would open the governors in heavy grass. Then I put a 16 HP Vanguard on and I hardly ever open the governors, it would only open the governors in tall heavy grass. I would say a 48" base works best with 16 HP or more.

 

 

 

Nothing wrong with the governor opening up for heavy grass that is what it is for. When the governor is opened up all the way it is using all 12HP. A bigger engine than what is needed will just waste more fuel.

 

Edited March 21, 2021 by Jim Turner

[Lee1977 7,037]

2 hours ago, Jim Turner said:

Nothing wrong with the governor opening up for heavy grass that is what it is for. When the governor is opened up all the way it is using all 12HP. A bigger engine than what is needed will just waste more fuel.

 

That my post and the 16 Vanguard used less gas then the 12 Kohler. I have a 18 Vanguard on it now and it's like the 520 will smoke the belts and not open the governors.  That just about the right amount of HP for a 48" deck.

 

 

[cschannuth 3,817]

I’m used to mowing with a 520 with a 48” deck. It mowed smooth as glass at full speed. I picked up a like new condition 2000 314-8 with 275 hours and a 42” deck a couple years ago. It cut nice but I had to use first gear in high range to obtain good cutting results. It surprised me since it runs perfect and the deck amd blades looks like new also. 

[SylvanLakeWH 27,532]

My 10 hp ran through this in 1st gear high...

 

 

[Jim Turner 42]

Impressive that your 16HP Vanguard would use less gas than that 12HP Kohler. Probably from a more efficient engine design, over head valves, higher compression. I suspect that vanguard has a much flatter torque curve too. I heard a lot of good things about the vanguards. Of topic but the 16HP K341 has about 14HP at 2600 RPM where the 16 Vanguard is 12.2HP at 2600 RPM. So it has more low end torque that would do a better job when under load and engine RPM drops. Of course also more gas.

Edited April 4, 2021 by Jim Turner

[DennisThornton 4,771]

Lots of good comments already, but I'll add that I think overall there are a lot of extra horses just riding along on a lot of tractors if all they are doing is mowing a lawn.  But mowing a maintained lawn is different than bush hogging a field or mowing one once or twice a year!  I mowed with a 8 hp 6 spd, 36" rear discharge for years and got the best cut this lawn ever got.  Went up to a 50" Toro and cut the time but also the quality of cut.  Doesn't take many horses to keep a well maintained lawn, and if there's a small area that grew too quickly just grab a lower gear for a few minutes.

[tom2p 2,394]

4 hours ago, DennisThornton said:

Lots of good comments already, but I'll add that I think overall there are a lot of extra horses just riding along on a lot of tractors if all they are doing is mowing a lawn. 

 

while this is largely true - when the size of the yard increases and especially if length of the grass increases or a grade is involved - cutting grass will possibly and probably put the most load on the engine 

turning soil (pulling plow) would be one exception - and operating two stage blower in heavy deep snow would be another exception 

 

Edited April 4, 2021 by tom2p

[tom2p 2,394]

On 3/21/2021 at 5:20 PM, cschannuth said:

I’m used to mowing with a 520 with a 48” deck. It mowed smooth as glass at full speed. I picked up a like new condition 2000 314-8 with 275 hours and a 42” deck a couple years ago. It cut nice but I had to use first gear in high range to obtain good cutting results. It surprised me since it runs perfect and the deck amd blades looks like new also. 

not a surprise 

 

520 Onan twin much larger / more powerful ... torque ... 782 cc

 

M14 Kohler single cylinder is 512cc 

 

I have 416-H (2) and a great running 312-8  - just 4hp difference - but the 416's feel like they have twice the power and that's barely an exaggeration 

 

on level ground cutting light grass - not so noticeable 

 

but cut heavy grass and especially when on a grade - night and day 

 

416-H Onan twin is 710 cc

 

Kohler M12 is around 476 cc 

 

Edited April 4, 2021 by tom2p