HP rating for attachments

   / HP rating for attachments #1  

putt_putt_green

Silver Member
Joined
Mar 10, 2007
Messages
204
Location
Western Central lower penisula MI
Tractor
JD 3520
If a boxblade (I'm looking at Woods) says that it is rated for 40-70 HP, which horsepower is this refererring to? Is it gross engine HP, net engine HP, or usable HP?

What are the consequences of running a 72" medium duty boxblade rated at 40-70 HP behind a 33 HP tractor? Their standard duty 72" boxblade is rated at 0-45 HP. Can someone tell me why the extra hundred pounds of steel on the medium duty boxblade requires more HP?
 
   / HP rating for attachments #2  
You are generally going to need 5 - 6hp per ft. for ground engaging equipment. I always just used the published HP in the specs but I guess with Hydrostatic drives there will be a usable HP rating as well.
That extra 100 Lbs of weight on the med duty will make the blade really dig and will need more HP
 
   / HP rating for attachments #3  
It's not that the heavier blades require the HP, but the other way around. They don't want someone bending up a blade by putting the smaller blade on a larger tractor.
 
   / HP rating for attachments #4  
Ford 850, is partially correct. (at least I agree with him - so he must be correct LOL!!) The max hp is to protect the attachment.

BUT, the HP range is the "working range" for tractors to effectively use the equipment. Mostly, it is assuming a 2WD tractor. They are really after an indirect correlation of hp with tractor size and effective traction. For 2wd tractors, more HP is usually found in a larger and heavier tractor. More weight gives better traction. If you look at the 4x4 series of box scrapers, you will see that the hp range is different.

I bought a decent woods (gannon landscaper) box. It is 66" wide and 900# or so. I wouldn't be able to pull it as well if it was an extra 6" wider and had an extra shank. Tractor is a Kubota L3410 HST. But that depends on soil, WI is similar to MI in that regard (even though we have a better football team LOL).

jb
 
   / HP rating for attachments #5  
putt putt green:

Welcome to TBN :D! I see nothing wrong with the information provided you. I go by the 1':5-6HP "Rule" using gross engine HP for the HP criteria when purchasing attachments and the "rule" works for me. I have not yet purchased a BB yet (so I could be talking out of my **** pore ;)) due to the constraints placed upon me by the "COMPTROLLER a.k.a. "SHE WHO MUST BE OBEYED" :(, but I am leaning towards a 60" M/HD model due to the heavy clay, rocky soil typical of NE based on a lot of research on the internet and here on TBN. Most of the thread replies on TBN suggest a BB that is heavy and slightly wider than your widest tire width. Interestingly in almost all cases the recommendations provided follow the "rule". The exceptions as it applies to BB's are for tractor operations in light loamy and sandy soils. Good luck on your research and acquisition. Prepare yourself for a lot of confusion, contradictory information, inconsistent data/opinions in your search. Most of the major tractor home websites have tractor selector software that based on your data input will recommend tractor models. The software appears heavily "loaded" towards FEL information and land size. Most of the "specifications" provided appear to be driven by Sales and Marketing Departments and the "spec" information is inconsistent as many brands "play" with how and where they take their measurements compared with the competition. Ask a lot of questions, sit on and drive all tractors of interest, and get a "feel" for the dealerships with whom you will ultimately be dealing. Dealer "feel" is as important as tractor "feel" IMHO as a good dealership will probably save you money in the long run. Beware there are many, many HP junkies :eek: in TBNland :p. Jay ;).
 
   / HP rating for attachments
  • Thread Starter
#6  
Thanks everyone. I'll go with the 1 foot to 6 gross engine HP rule, which should put me on the safe side. The Woods 6' boxblade is rated at 1:6.66 HP, which is probably Woods just covering themselves. From what I've read in other posts, the heavier duty, the better.
 
   / HP rating for attachments #7  
I have a 6' united box blade. It is more of a standard duty unit. It will still fill up with soil easily with the right top link adjustment and my 28hp hydro tractor will pull it with ease.
 
 
 
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